Antitumor Effects of Ganoderma lucidum polysaccharides and their Clinical Applications: An Updated Review

Abstract

Ganoderma lucidum polysaccharides (GLPs), the major bioactive components of Ganoderma lucidum, have attracted increasing attention due to their broad-spectrum anti-tumor activities and favorable safety profile. GLPs have demonstrated considerable anti-cancer potential through both direct tumoricidal and immunomodulatory mechanisms. GLPs regulate multiple signaling pathways, including caspase-mediated and mitochondrial apoptosis, Fas death receptor signaling, and cAMP/PKA modulation, ultimately promoting tumor cell death. GLPs function as potent immunomodulators by enhancing dendritic cell maturation, activating T and B lymphocytes, and stimulating macrophage-mediated cytotoxicity, thereby reshaping the tumor immune microenvironment. Clinically, GLP preparations have been applied as adjuvant therapies to conventional cancer treatments to reduce toxicity and improve patient outcomes. Herein, this review systematically summarizes current evidence on the anti-tumor mechanisms of GLPs and evaluates their potential clinical applications in cancer therapy, highlighting their therapeutic potential.

Introduction

Cancer is the second leading cause of death worldwide, with nearly 20 million new cancer cases and more than 9.7 million cancer-related deaths occurring annually. ¹ Moreover, cancer incidence and mortality are still increasing annually, and the number of new cancer cases is expected to reach 35 million by 2050, ² posing a serious threat to human life and health. For different types of cancer, clinical management strategies involving various treatments, such as surgery, radiotherapy, interventional therapy, targeted therapy, immunotherapy, and traditional Chinese medicine (TCM), have been developed and achieved positive clinical therapeutic effects.

Compared to other treatments, TCM has been shown to have therapeutic effects such as improving the physical condition, immunity, and pain of patients with cancer, as well as reducing the toxic side effects of drugs, ³ significantly improving patients’ quality of life and playing a unique role in cancer treatment. Among TCMs with antitumor effects, Ganoderma lucidum is a popular drug. This fungus, is listed in the American herbal pharmacopoeia and Chinese pharmacopoeia. In addition, it is the only drug that enters the five meridians in the material medica, which is tonic to the heart, liver, spleen, lung, kidney, and other organs. It has been shown enhancing systemic immunity, highlighting its potential in antitumor clinical applications. ⁴ It has been proven to enhance systemic immunity, indicating important application prospects in antitumor clinical applications.^4,5 Modern medical research has shown that Ganoderma lucidum has diverse biological activities.

Many studies have examined the antitumor components of Ganoderma lucidum, including monosaccharide, nucleosides, furans, sterols, alkaloids, triterpenoids, oils, amino acids, and proteins, as well as minerals such as potassium, calcium, phosphorus, magnesium, selenium, iron. ⁶ They found that GLPs and triterpenoid components are the primary mediators of its antitumor effects.^7,8 GLPs are helical macromolecules composed of three strands of monosaccharide chains. Their triple-helical conformation are similar to that of DNA and RNA. Structurally, they are primarily (1→3)- and (1→6)-linked α/β-glucans, and can also exist as glycoproteins or water-soluble heteropolysaccharides. ⁹ GLPs act directly or indirectly on tumor cells to exert anti-tumor effects, including antiproliferative, pro-apoptosis, anti-metastasis, anti-angiogenic, anti-inflammatory, anti-oxidant, and immune modulation mechanisms. GLPs inhibit tumor growth and metastasis, and enhance patients’ immune functions.^10,11

This review aims to systematically summarize current research on GLPs, covering their structural characterization, anti-tumor molecular mechanisms, and immunomodulatory activities, and to critically evaluate their clinical application prospects. By integrating existing evidence, this review aims to clarify the therapeutic potential of GLPs as natural anticancer agents and to facilitate their further development toward standardized, evidence-based, and globally applicable cancer therapeutics.

Structural Characteristics of GLPs

GLPs are an active ingredient extracted from Ganoderma lucidum fruiting bodies or spore powder, which exists in the cell wall and is readily soluble in water but not in organic solvents. More than 200 types of GLPs have been identified, which can be classified as homopolysaccharides and heteropolysaccharides according to their chemical composition. Most of them are heteropolysaccharides, which are primarily composed of one or more monosaccharides, such as glucose, arabinose, galactose, mannose, xylose, and rhamnose, linked by α-glycosidic or β-glycosidic bonds. ¹² The composition of monosaccharides may differ among sources of GLPs. Most monosaccharides in GLPs mainly contain glucose and galactose, while some also contain mannose, arabinose, and caramel. Polysaccharide can be further classified into α-type and β-type based on the isotropic structure of the monosaccharides, β-type polysaccharides have received extensive attention from researchers as the main active structure, while the activity of α-type polysaccharides relatively less studied.

Overall, the chemical composition of GLPs is complex, with varying molecular weights. Generally, their biological activities increase with molecular weights. To a certain extent, the numbers of branched chains, the number of monosaccharides, and biological activity increase with the main chain length of GLPs. ¹³ Systematic studies have examined the structures of more than 200 GLPs, of which more than 20 have been identified (Table 1).

Table 1.

Biological Activities of Structurally Diverse GLPs Obtained via Different Extraction Methods

Designation	Quantity Contained	Characterization	Extraction Method	Biological Outcomes	References
GLPw	23.24%	Brown flake	Hot-water extraction	Scavenging DPPH free radicals	Li et al 14
GLPf	23.00%	Brown flake	Repeated freezing and thawing method	Scavenging hydroxyl radicals	Liang et al 15
GLPf30	16.93%	Brown flake	Ethanol grading method	Scavenging DPPH free radicals	Liang et al 15
GLPf60	23.38%	Brown flake	Ethanol grading method	Scavenging hydroxyl radicals	Liang et al 15
GLPf80	36.49%	Brown flake	Ethanol grading method	Scavenging DPPH free radicals	Liang et al 15
GLP40	45%	Brown flake	Grading of different ethanol concentrations	Antioxidant activity	Li et al 16
GLP60	29%	Brown flake	Grading of different ethanol concentrations	Antioxidant activity	Yang et al 17
GLP80	26%	Brown flake	Grading of different ethanol concentrations	Scavenging hydroxyl radicals, Scavenging DPPH free radicals, Total antioxidant capacity	Yang et al 17
GLP-1 (G.lucidum. substrate）		D-galactoglucan in linear conformation	Ultrasonic extraction method	Antioxidant activity, Anti-tumor proliferation effect, Immunomodulatory activity	Alzorqi et al 18
GLP-2 (G. lucidum substrate)		Beta-d-glucan in spherical conformation	Column level analysis method	Antioxidant activity, anti-tumor proliferation effect, immunomodulatory activity	Wen et al 19
GLP (G. lucidum mycelium crude polysaccharides)	96.10%		DEAE-52 cellulose anion exchange method	Antioxidant activity, anti-tumor activity	Ding et al 20
A-GLP (G. lucidum mycelium crude polysaccharides)	92.24%		DEAE-52 cellulose anion exchange method	Antioxidant activity, anti-tumor activity	Hu et al 21
S-GLP	89.73%		DEAE-52 cellulose anion exchange method	Antioxidant activity, anti-tumor activity	Li et al 22
WGLP (G. lucidum mycelial total sugars)	7.6%		Water Drawing	Antioxidant activity	Ren et al 23
AGLP (G. mycelium total polysaccharides)	28.8%		Alkaline extraction	Antioxidant activity	Lu et al 12
TGLB1		Pyran-type glucans mainly with β-(1→3) and (1→6) glycosidic bonds		Immunomodulatory activity	Liu et al 24
TGLB8				Immunomodulatory activity	Shi et al 25
TGLB10				Immunomodulatory activity	Shi et al 25
LZJ-0.15		Glc(β-1→ and →6)Glc(β-1→ linked primarily glucan	Gel filtration chromatography analysis	Immunomodulatory activity	Wang et al 26
PSG-1			Step-by-step extraction with hot water and lye	Anti-tumor activity, antioxidant activity, immunomodulatory activity	Zhang et al 27
GLFP			Asymmetric field-flow separation	Anti-tumor activity	Guo et al 28
GLSP2			Asymmetric field-flow separation	Anti-tumor activity, immunomodulatory activity	Ma et al 29
G. lucidum desiccated spore powder polysaccharide				Anti-inflammatory and anti-tumor activity	Liu et al 30
Wall-broken spore powder polysaccharide				anti-tumor activity	Li et al 14
G.lucidum water-soluble polysaccharide (WSG)				Antioxidant activity, anti-tumor proliferation effect	Li et al 22

Antitumor Effects of GLPs

Due to their inherently low cytotoxicity, it was initially proposed to use GLPs as an immunomodulator to facilitate clinical anti-tumor therapy. However, as research progressed, they were found to exert certain inhibitory effects on various cancers, including osteosarcoma, melanoma, breast, gastric, and hepatocellular carcinoma. ¹³

For instance, GLPs have been reported to effectively inhibit the proliferation, migration, and invasion of human osteosarcoma MG63 and U2-OS cells while simultaneously inducing apoptosis, indicating their potent cytotoxic and anti-metastatic effects in osteosarcoma models. In another study, co-incubation of MDA-MB-231 (triple-negative breast cancer) and B16-F10 (melanoma) cells with varying concentrations of GLPs significantly suppressed tumor cell proliferation. At concentrations above 250 µg/mL, GLPs significantly reducing the cell viability of both cancer types in a time and concentration-dependent manner. These findings suggest that GLPs can be used in the treatment of melanoma and triple-negative breast cancer. ³¹ A Chinese study further explored the inhibitory effect of GLPs on gastric cancer, using human gastric cancer cell lines MKN28, AGS, NCI-N87, and GES-1. It confirmed that GLPs could significantly reduce the viability of gastric cancer cells and induce apoptosis. The half-maximal inhibitory concentration (IC₅₀) is 5.36 ± 2.58 mg/ml for a 48 h incubation. ³²

Additionally, another study evaluated the effect of GLPs in a murine hepatocellular carcinoma (HCC) model in vivo. In this study, the mouse hepatoma cell line Hepa1-6 was used to establish a transplanted tumor model, and different doses of GLP (100 and 200 mg/kg) were administered by gavage daily for 14 days. The results showed that GLP could significantly inhibit the growth of Hepa1-6 xenografts in a dose-dependent manner, with the highest inhibition rate of 65%. ³³ This in vivo data indicates that GLP exert promising therapeutic effects against hepatocellular carcinoma.

Collectively, these findings indicate that GLPs possess significant anti-tumor activity across various solid malignancies. This provides a strong scientific rationale for their further development and clinical application in cancer therapy.

Anti-Tumor Mechanisms of GLPs

GLPs exert potent anti-tumor effects through multiple mechanisms, including inhibition of tumor cell proliferation, induction of apoptosis, and suppression of invasion and metastasis. Moreover, GLPs modulate key intracellular signaling cascades via multi-target molecular interactions, ultimately disrupting tumor growth and survival. Overall, the anti-cancer actions of GLPs are mediated through several major signaling pathways, as summarized below.

Apoptotic Pathway

The key molecular mechanisms underlying the anti-tumor effects of GLPs are summarized in Figure 1. GLPs have been shown to regulate multiple intracellular signaling cascades that are crucial for tumor cell survival and apoptosis. Primarily, GLPs activate both the endogenous apoptotic pathways, which include the caspase-dependent signaling, mitochondrial pathway, and cAMP/PKA signal transduction, and exogenous apoptotic pathway, mediated through the Fas cell surface death receptor. By targeting these pathways, GLPs effectively disrupt tumor cell energy homeostasis and survival signaling, leading to growth inhibition and apoptosis induction. These findings demonstrate that GLPs exert multi-targeted molecular regulatory effects, contributing to their broad anti-tumor activities across diverse cancer types.

Figure 1.

Molecular mechanisms of GLP-induced apoptosis in tumor cells.

Caspase-Dependent Signaling

Caspases are cysteine-dependent aspartate-specific proteases that act as central executors of apoptosis. ³⁴ Multiple studies have confirmed the involvement of caspase signaling in GLP-induced tumor cell death. Zhong et al ³⁵ found that GLPs, Ganoderma lucidum Polysaccharide fraction 5 (GLP5) dose-dependently upregulated cleaved caspase-3 (CASP3) and pro-apoptotic BCL2-associated X (BAX), and downregulated anti-apoptotic BCL2 apoptosis regulator (BCL-2) in Junket cells, indicating activation of caspase-dependent apoptosis. Similarly, Bai et al ³⁶ found that treating HCT-116 cells with enzymatically hydrolyzed GLPs (EGLP), dose-dependently upregulated BAX expression and CASP3 levels. Yang et al ³⁷ further showed that treating HL-60 cells with GLPs, dose-dependent significantly increased the expression of BCL-2, and BCL-2 like 1 (BCL2L1/BCL-XL) and CASP3 levels. Together, these studies reveal the important role of CASP3 in apoptosis regulation and demonstrated that GLPs induce apoptosis in tumor cells by modulating the caspase signaling pathway.

Mitochondrial Pathway

Mitochondria are the “switch” of apoptosis regulation in tumor cells, and their abnormal functions are closely related to tumorigenesis and treatment resistance. The mitochondrial pathway's involvement in anti-tumor activity is related to the release of cytochrome C (CYCS), activation of caspase cascade, regulation of BCL-2 family proteins, and open of mitochondrial membrane permeability transition pore (MPTP). GLPs have been shown to impair mitochondrial membrane potential, promoting the release of CYCS, activation of CASP9 and CASP3, and subsequent apoptotic vesicle formation. For example, Shang et al ³⁸ found that GLPs significantly inhibited breast cancer growth in a dose-dependent manner. GLPs disrupted the mitochondrial membrane potential and, increased CYCS levels. Gao et al ³⁹ found that selenium-containing GLPs (Se-GLPs) could promote apoptosis and inhibit proliferation in breast cancer cells by disrupting mitochondrial membrane potential, increasing the CYCS level and activating CASP3, CASP9, and poly ADP-ribose polymerases (PARP). These studies support that regulation of mitochondrial integrity and permeability transition is a major route by which GLPs trigger apoptosis.

cAMP/PKA Signaling Pathway

The cyclic adenosine monophosphate (cAMP) / protein kinase A (PKA) signaling pathway is an important intracellular second messenger system widely involved in proliferation, metabolic regulation, and stress response. Several studies have confirmed that GLPs promote tumor apoptosis through the cAMP/PKA signaling pathway. Xu et al ⁴⁰ found that GLPs significantly increased cAMP, PKA and adenylate cyclase activities in tumor upregulating the protein expression of PKA and downregulating the protein expression of protein kinase C. Zhang et al ²⁷ demonstrated that PSG-1 significantly increased cAMP and PKA activities. It significantly increased PKA protein levels and decreased PKC and intracellular Ca²⁺ levels, the activation of cAMP/PKA signaling pathway, and inactivation of the Ca²⁺/PKC signaling pathway, by GLPs lead to inhibition of apoptosis and tumor growth. These results suggest that GLPs promote tumor cell death partially by shifting the balance toward cAMP/PKA pro-apoptotic signaling.

Fas Cell Surface Death Receptor

The Fas signaling pathway represents a major extrinsic apoptotic mechanism, initiated by death receptors located on the cell surface and closely associated with immune regulation and tumor immune evasion. Upon Fas ligand (FasL) binding, Fas receptors recruit Fas-associated death domain protein (FADD), leading to the assembly of the death-inducing signaling complex (DISC). This complex subsequently activates caspase-8, triggering the downstream caspase cascade and ultimately resulting in apoptosis.

Several studies have confirmed that GLPs promote apoptosis by triggering the Fas-mediated extrinsic apoptotic pathway. Chen et al ⁴¹ demonstrated that treatment of HepG2 cells with G. lucidum fruiting-body polysaccharides (GLFPs) and G. lucidum sporoderm-breaking polysaccharides (GLSPs) induced apoptosis by upregulating FAS, FASL, and CASP8 mRNA levels, thereby activating the Fas signaling pathway. Consistently, Liang et al ⁴² reported that GLPs increased CASP8 activity and elevated the expression of FAS and cleaved CASP3 in HCT-116 colon cancer cells, confirming activation of Fas-mediated apoptosis. In a separate study, Liang et al ⁴³ further demonstrated that GLPs enhanced the expression of Fas and apoptotic caspases while reducing cleaved PARP levels, indicating caspase-dependent apoptotic execution. Additionally, Gabriella et al ⁴⁴ reported that GT-derived polysaccharides pro-CASP9, pro-CASP3, CYCS, and PARP expression, supporting the involvement of both extrinsic and intrinsic apoptotic pathways. Collectively, these findings indicate that GLPs trigger tumor cell apoptosis, at least in part, by activating the Fas/FADD/CASP8 signaling cascade, leading to downstream executioner caspase activation and cell death.

GLPs trigger programed cell death through multiple apoptotic pathways: (A) Fas-mediated extrinsic pathway: GLPs enhance Fas receptor activation on the tumor cell surface, leading to recruitment and activation of caspase-8, thus initiating the apoptotic cascade. (B) Mitochondrial (intrinsic) pathway: GLPs induce intracellular stress and mitochondrial outer membrane permeabilization (MOMP), resulting in cytochrome c release and apoptosome formation, which activates caspase-9. (C) Caspase execution pathway: Both extrinsic and intrinsic apoptotic signals converge on the caspase-3-dependent execution cascade, leading to the cleavage of critical cellular substrates and apoptotic cell death. (D) cAMP/PKA signaling modulation: GLPs regulate cAMP/PKA signaling, which interacts with both apoptotic pathways to fine-tune the magnitude of apoptosis and enhance tumor-specific cytotoxicity.

Antioxidative Protection Against DNA Damage

Excessive accumulation of reactive oxygen species (ROS) and other free radicals derived from cellular metabolism, UV exposure, environmental toxins, and chronic inflammation can induce oxidative DNA damage. Such damage, including DNA strand breaks, oxidation, and replication errors, lead to genomic instability and irreversible mutations. Over time, these alterations may activate oncogenes or disable tumor suppressor genes, thereby promoting malignant transformation, uncontrolled cell proliferation, and cancer development. Therefore, enhanced antioxidative defense represents a critical mechanism for preventing tumor initiation and progression.

Multiple studies have demonstrated that GLPs exert substantial antioxidant and DNA-protective effects. Seweryn et al ⁴⁵ demonstrated that GLPs promoted proliferation, differentiation, activation, while regulating nitric oxide (NO) production, In addition, GLPs inhibited the aging of endothelial cells, and decrease plasma levels of superoxide dismutase (SOD) and malondialdehyde (MDA), and indirectly scavenge oxygen free radicals and increased glutathione peroxidase (GPX) levels. Similarly, Yu et al ⁴⁶ showed that GLPs significantly increased the activities of major antioxidant enzymes including the antioxidant enzyme activities of SOD, GPX and catalase (CAT) and lactate dehydrogenase (LDH). As a results, the GLPs enhance the body's capacity to neutralize excessive ROS and ameliorate oxidative stress. Further studies revealed that GLPs maintain DNA integrity by scavenging hydroxyl radicals, preventing oxidative base modification such as 8-OHdG formation, and supporting DNA repair pathways, ultimately reducing mutation accumulation in tumor-prone tissues. These findings indicate that the reduction of oxidative damage may serve as a vital upstream mechanism through which GLPs prevent carcinogenesis and suppress tumor progression^{47, 48}

Collectively, GLPs enhance endogenous antioxidant defenses, preserve genomic stability, and mitigate ROS-induced DNA lesions, thereby contributing significantly to their anti-tumor pharmacological effects.

Immunomodulatory Mechanisms

Cancer immunotherapy enhances anti-tumor responses by promoting tumor antigenrecognition, restoring immune surveillance, and remodeling the immunosuppressive tumor microenvironment. As a natural bioactive macromolecule, GLPs have been widely recognized as potent immunomodulators capable of regulating both innate and adaptive immune responses.

GLPs exert broad immunoregulatory effects by modulating the proliferation, activation, and effector functions of diverse immune cells. In addition, GLPs stimulate the secretion of multiple cytokines, chemokines, and growth factors, thereby enhancing immune cell differentiation and cytotoxic activity while promoting antigen presentation and tumor clearance. Through these coordinated immune responses, GLPs contribute to both innate immune activation and adaptive immune priming, ultimately strengthening systemic anti-tumor immunity and suppressing tumor progression ²³ (Figure 2).

Figure 2.

Overview of the immunomodulatory effects of GLPs in anti-tumor immunity. (A) T cell immune responses: GLPs enhance antigen uptake, processing, and presentation by antigen-presenting cells, thereby promoting T-cell priming. They also provide co-stimulatory signaling and stimulate cytokine production (eg, IL-12), supporting the activation and clonal expansion of naive T cells. Activated cytotoxic T lymphocytes (CTLs) subsequently migrate into tumor tissues, recognize tumor-associated antigens, and induce cancer cell death. (B) B cells immune responses: GLPs activate B cells following antigen recognition through the B-cell receptor with assistance from T cells. Activated B cells proliferate and differentiate into antibody-secreting plasma cells. Tumor-specific antibodies contribute to anti-tumor immunity through multiple effector mechanisms. (C) TLR4-p38 MAPK/NF-κB signaling pathway in macrophages: GLPs bind to TLR4 on macrophages, leading to simultaneous activation of p38 MAPK and NF-κB signaling cascades. These pathways synergistically induce transcription and translation of TNF-α, resulting in increased synthesis and secretion of TNF-α and subsequent enhancement of macrophage-mediated tumoricidal activity. The accompanying Table 2 summarizes their key mechanisms of action-including apoptotic pathway, antioxidative protection against DNA damage and exert the immune function, along with their associated molecular targets and signaling pathway.

Table 2.

Summary of the Pharmacological Activities and Mechanism of GLPs.

Pharmacological Activity	Target/pathway	Mechanism	References
Apoptotic pathway	Caspase-dependent signaling	GLPs induce apoptosis in tumor cells by modulating the caspase signaling pathway, and dose-dependent significantly increase the expression of BCL-2, and BCL2L1/BCL-XL (BCL-2 like 1) and CASP3 levels	35–37
	Mitochondrial pathway	GLPs predominantly act through the mitochondrial apoptotic pathway, leading to cytochrome C (CYCS) release. This process involves modulation of BCL-2 family proteins and opening of the mitochondrial permeability transition pore (MPTP), resulting in disruption of the mitochondrial membrane potential and further CYCS elevation. Subsequently, the caspase cascade is robustly activated, as evidenced by cleaved CASP9 and CASP3, along with PARP cleavage, collectively driving apoptotic vesicle formation	38,39
	cAMP/PKA signaling pathway	GLPs activate the cAMP/PKA signaling pathway by enhancing cAMP production and adenylyl cyclase activity, resulting in PKA upregulation. This is accompanied by a corresponding reduction in PKC expression and intracellular Ca2⁺ levels, which collectively contribute to the suppression of the Ca2⁺/PKC pathway	27,40
	Fas cell surface death receptor	GLPs promote tumor cell apoptosis primarily by activating the extrinsic Fas-mediated pathway. They upregulate the expression of FAS, FASL, and CASP8, leading to the assembly of the death-inducing signaling complex (DISC) via FADD recruitment upon Fas–FasL interaction. This triggers caspase-8 activation, which initiates the downstream caspase cascade—including executioner caspases such as caspase-3—resulting in caspase-dependent apoptotic cell death.	41–44
Antioxidative Protection Against DNA Damage	DNA strand breaks, oxidation, and replication errors 48,49,50,51	GLPs can inhibit the senescence of endothelial cells, reduce the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in plasma, indirectly scavengers the levels of oxygen free radicals and glutathione peroxidase (GPX), and enhance the ability of the body to neutralize excessive ROS and improve oxidative stress. Moreover, it maintains DNA integrity by scavenging hydroxyl radicals, preventing oxidative base modifications such as 8-OHdG, and supporting DNA repair pathways, ultimately reducing the accumulation of mutations in tumor-susceptible tissues	45–48
exert the immune function	Stimulation of dendritic cell differentiation and maturation	DCs inhibit tumors through antigen presentation, t cell activation, and modulation of the immune microenvironment.GLPs treatment increase the expression of a key co-stimulatory molecule, intercellular adhesion molecule-1 (ICAM-1) on DCs GLPs can also promote the differentiation, maturation and antigen presentation ability of DCS through TLR4 - and NF-κB-dependent mechanisms, and ultimately enhance t cell-mediated anti-tumor immunityEnhanced secretion of IL-12B/p40, IL-10 and IL-23.	49–53
	T cells activation	GLPs significantly enhance T cell proliferation, modulate surface phenotype expression, and augment IL-2 production capacity. They elevate T cell DNA polymerase activity, increase both the quantity and functional competence of T cell subsets—including cytotoxic T lymphocytes (CTLs)—and specifically expand the CD8⁺ T cell population. Furthermore, GLPs potentiate the antigen-specific cytolytic activity of T cells against tumor cells, primarily through upregulation of major histocompatibility complex class I (MHC-I) molecules and costimulatory molecules on antigen-presenting cells or tumor cells.	54–56
	B cell activation	GLPs have been shown to enhance B-cell activation and functional capacity, upregulate the surface expression of transferrin receptor (TFRC/CD71) and interleukin-2 receptor alpha chain (CD25), augment immunoglobulin and IL-2 secretion, and promote the proliferation of murine splenic lymphocytes. As key mediators of adaptive immunity, B cells contribute critically to immune regulation and homeostasis through antibody production and cytokine secretion.	57,58
	Macrophage Activity	GLPs activate the TLR4 receptor on the macrophage surface, triggering the p38 MAPK signaling pathway. This leads to the activation of the transcription factor NF-κB, which initiates TNF-α transcription and subsequently promotes TNF-α synthesis and secretion, ultimately enhancing the anti-tumor function of macrophages. Together, these findings demonstrate that GLPs activate macrophages through TLR4-dependent MAPK and NF-κB signaling pathways	59–61

Stimulation of Dendritic Cell Differentiation and Maturation

Dendritic cells (DCs) are the most potent professional antigen-presenting cells and serve as a critical bridge between innate and adaptive immunity. DCs combat tumors through antigen presentation, T-cell activation, and regulation of the immune microenvironment. Chen et al ⁴⁹ showed that GLPs, a biologically active β-glucan, could stimulate monocyte-derived DC maturation and induce the differentiation of monocytic leukemia cells into functional DCs with enhanced immunostimulatory activity. Lin et al ⁵⁰ further showed that GLPs treatment altered the transcriptional profile of human DCs and promoted a Th1-biased immune response in BALB/c mice, suggesting improvements in anti-tumor immunity. Moreover, Lin et al ⁵¹ found that treatment with PS-G, a branched (1→6)-β-D-glucan fraction of GLPs, increased the cell surface expression of key costimulatory molecules on DCs including CD8, CD86, CD83, CD40, intercellular adhesion molecule 1(ICAM1) /CD54, and human leukocyte antigen (HLA-DR), as well as increased the levels of the IL-12/p70, its subunits IL12A/p35 and IL12B/p40, as well as IL-10 production. In addition, PS-G also enhanced T-cell activation and promoted elevated T-cell release of IFN-γ and IL-10 while suppressing endocytic ability, a hallmark of DC maturation. Mechanistic investigations indicated that Toll-like receptor 4 (TLR4), an essential pattern recognition receptor, mediates these immunoregulatory effects, as TLR4 blockade attenuated PS-G-induced IL-12B/p40 and IL-10 expression, confirming the involvement of TLR4-dependent signaling. ⁵² Lin et al ⁵³ further reported that GLP-derived recombinant LZ-8 enhanced DC maturation by increasing cell surface expression of CD80, CD86, CD83, and HLA-DR, accompanied by increased secretion of IL-12B/p40, IL-10, and IL-23. rLZ-8 treatment also activated inhibitor of κB kinase (IKK) and nuclear factor-κB (NF-κB), and promoted mitogen-activated protein kinase (MAPK) phosphorylation, indicating the activation of key innate immune signaling pathways. Collectively, these findings demonstrate that GLPs can promote DC differentiation, maturation, and antigen-presenting capacity through TLR4 and NF-κB-dependent mechanisms, ultimately enhancing T-cell-mediated anti-tumor immunity.

T Cells Activation

T cells play a central role in anti-tumor immunity by recognizing and eliminating malignant cells. however, tumors evade immune attack through various mechanisms, and immunotherapy enhance their activity by reducing T cell inhibition or enhancing T cell function. Li et al ⁵⁴ experimentally confirmed that moderate amounts of GLPs could significantly increase T cells’ proliferation, surface phenotypic expression and ability to induce IL-2, and enhance the activity of T cell, DNA polymerase and increase the number and function of T cell subclasses and functions. Zhou et al ⁵⁵ demonstrated that GLPs could enhance the killing effect of T cells on tumor cells by inducing major histocompatibility complex class I molecules and co-stimulatory molecules. Shao et al ⁵⁶ demonstrated that GLPs could enhance cytotoxic T cell (CTL) activity, increase the number of CD8 ⁺T cells, activate and improve tumor-cell-specific killing, enhancing the immunocompetence of T cells in tumor-bearing mice. These findings collectively demonstrate that GLPs enhance anti-tumor immunity by promoting T-cell activation, proliferation, and effector function, making them promising immunomodulatory agents for cancer therapy.

B Cell Activation

B cells contribute to anti-tumor immunity by producing antibodies and cytokines, regulating immune responses, and maintaining immune homeostasis. Multiple studies have shown that GLPs can enhance B-cell activation and function. Gao et al ⁵⁷ investigated two groups of water-soluble GLPs (GLPD1 and GLPD2) extracted from the seeds of a Ganoderma lucidum. Both polysaccharide fractions exhibited immunological activity, and GLPD2 had significant quantitative and qualitative correlations with splenic lymphocyte proliferation. Lin et al ⁵⁸ demonstrated that Ganoderma lucidum proteoglycans induced B cells surface expression of transferrin receptor TFRC/CD71 and CD25, increased immunoglobulin secretion, and promoted IL-2 secretion to stimulate the proliferation of mouse splenic lymphocytes. These findings indicate that GLPs can activate B cells, promote antibody generation, and enhance humoral immunity, which collectively contribute to their anti-tumor immunomodulatory effects.

Macrophage Activity

Macrophages are essential effector cells of the innate immune system that contribute to anti-tumor immunity through direct tumor cell killing, phagocytosis, and activation of adaptive immune responses. Multiple studies have demonstrated that GLPs can enhance macrophage activation and effector function. Guo et al ⁵⁹ demonstrated that GLPs could activate the immune receptor TLR4, thereby activating macrophages through the TLR4/NF-κB pathway. Zhang et al ⁶⁰ demonstrated that GLPs acted on TLR4 on macrophage membranes, thereby activating the p38 MAPK signaling pathway. TLR4 activates the p38 MAPK signaling pathway, which activates the transcription factor NF-Kβ, initiating the transcription of TNF/TNF-α. Ultimately, TLR4 increases the synthesis and secretion of TNF-α, and improves the anti-tumor activity of macrophages. Lu et al ⁶¹ demonstrated that GLPs significantly enhanced multiple functions of peritoneal macrophages, including viability, phagocytic activity, the production of NO and TNF-α, as well as the cytotoxicity against B16F10-CS melanoma cells. In addition, GLPs could completely or partially inhibit TNF-α activity. Collectively, these findings indicate that GLPs enhance anti-tumor immunity by activating macrophages through TLR4-dependent MAPK and NF-κB signaling pathways, strengthening their roles in tumor cell clearance and immune regulation.

Emerging Research Fields of GLPs

With the rapid development of modern analytical and computational technologies, research on Ganoderma lucidum polysaccharides (GLPs) is progressing from traditional pharmacological investigations toward more precise structural and mechanistic exploration. Among these advances, multi-omics analysis, structure–activity relationship studies, and molecular docking have become key drivers for developing GLPs into promising anti-tumor therapeutics.

Multi-omics technologies, including genomics, transcriptomics, proteomics, and metabolomics, provide systematic insights into GLP biosynthesis and regulatory networks. Xie et al ⁶² identified key genes associated with fungal growth, secondary metabolite biosynthesis, and signal transduction, laying a foundation for elucidating the molecular basis of G. lucidum's therapeutic activity. Luo et al ⁶³ emphasized the importance of integrating molecular biology, genetic engineering, and omics strategies to improve the yield and pharmacological performance of GLPs and triterpenoids. Using transcriptomic profiling and network construction, Cheng et al ⁶⁴ clarified potential anti-tumor mechanisms of GLPs in THP-1 cells. Meanwhile, Ma et al ⁶⁵ applied proteomics to identify immune-related target proteins of GLSPs, providing molecular evidence for their immunoregulatory effects.

Structural characteristics are crucial determinants of GLP biological activity. Du et al ⁶⁶ reported that molecular weight, branching degree, glycosidic linkages, and helical conformation influence solubility, bioavailability, and immune response. Liu et al ⁶⁷ and Wang et al ⁶⁸ showed that raw materials and extraction methods lead to variations in monosaccharide composition and structural complexity, resulting in differences in therapeutic performance. Tang et al ⁶⁹ found that ultrasonic and enzymatic treatments enhance structural features contributing to antioxidant effects. Deng et al ⁷⁰ identified β-(1→3,1→6)-glucan as a key motif for immune activation, while Fu et al ⁷¹ demonstrated that chain length and branching frequency significantly impact biological potency. These findings highlight the necessity of precise structural characterization and standardization for consistent clinical efficacy.

Molecular docking also contributes to mechanistic understanding at the protein, polysaccharide interaction level. Shen et al ⁷² showed that differential binding affinities of sulfated and non-sulfated GLPs to human serum albumin (HSA) may influence stability and transport in vivo. Additionally, Ignat et al ⁷³ used Hi-C–assisted genome assembly to identify genes associated with GLP biosynthesis, providing a basis for metabolic engineering and improved druggability of GLP-derived products.

Anti-Tumor Clinical Applications of GLPs

GLPs have been widely applied in clinical oncology as adjuvant therapeutic agents due to their potent immunomodulatory effects and low toxicity. When used in combination with radiotherapy or chemotherapy, GLPs can alleviate treatment-related adverse effects, reduce the required dosage of cytotoxic drugs, and mitigate myelosuppression, thereby improving treatment tolerance and patient quality of life. Studies have demonstrated that GLP-based interventions can synergize with conventional tumor therapies to enhance therapeutic efficacy while minimizing systemic toxicity.

In China, ZIZHI polysaccharide tablets were approved in 2010 as an adjuvant treatment for leukopenia and hematopoietic damage caused by cancer chemotherapy and radiotherapy. ⁷⁴ In addition, several fungal polysaccharides, including those derived from Ganoderma lucidum, Lentinus edodes (shiitake mushroom), and Poria cocos, have been approved by the National Health Authorities as clinical immunotherapeutic agents for cancer management. In Japan, GLPs have long been incorporated into standard treatment regimens as adjuncts to chemotherapy and radiotherapy, demonstrating promising benefits in immune function recovery and treatment outcomes. ⁷⁵ Fungal polysaccharides from food and medicinal herbs have been widely used in clinically treating diseases such as immunodeficiency disorders, autoimmune diseases, and tumors, highlighting their role as biological response modifiers (BRMs) capable of regulating the immune system and enhancing anti-cancer defense. ⁷⁶ Therefore, GLPs are recognized as key contributors to supportive cancer care and immunotherapy.

Despite their growing clinical adoption, current GLP preparations also exhibit limitations, such as insufficient structure–activity relationship data, inconsistency in extraction and purification methods, and variability in clinical efficacy due to heterogeneous chemical compositions. These challenges underscore the need for standardized production protocols, optimized delivery systems, and deeper mechanistic understanding to fully harness the therapeutic potential of GLPs in cancer therapy.

Currently, independently marketed GLP products. In China do not have a specific molecular conformation, their pharmacological mechanism is unclear. The level of evidence-based medicine is weak, and their international recognition is low, making it harder for them to enter the international market. The anti-tumor effects of GLPs vary significantly depending on the species and origin of G. lucidum, extraction processing, and the structural characteristics of polysaccharides, including molecular weight, monosaccharide composition, branching patterns, conformation, and glycoprotein content. The complexity and microscopic inhomogeneity of the polysaccharide structure make GLP isolation and purification challengingly. Analyzing the primary structure of GLPs (ie, the composition of monosaccharides and their sequences) and determining the correct structural formulas are difficult, making it impossible to study their formational relationships. In addition, technical conditions have greatly limited studying GLPs. If the monomers with definite structures can be isolated from GLPs using advanced separation and analysis techniques, their anti-tumor mechanism can be determined and combined with clinical practice for more in-depth research and application. Such studies are a great significance for applying in clinical research in China and international field. Many uncertainties remain regarding the specific mechanisms of action underlying GLPs’ anti-tumor effects, knowledge of their anti-tumor mechanisms remains at the cellular level without further exploration at the molecular level. Further exploration of the molecular biology of GLPs and the reproducibility of their molecular targets and pathways in animal studies is vital to advance knowledge on their anti-tumor effects. Future progress in these areas will be essential for promoting the standardized development, regulatory approval, and international clinical application of GLPs as reliable anti-cancer therapeutics.

Summary

GLPs as the major bioactive constituents of G. lucidum, have demonstrated considerable anti-tumor potential through their multi-targeted biological activities. GLPs exert anti-cancer effects primarily by inhibiting tumor proliferation, inducing apoptosis, modulating oxidative stress, suppressing angiogenesis and metastasis, and enhancing host immune responses. Molecular mechanism studies reveal that GLPs regulate both intrinsic and extrinsic apoptotic pathways, including the mitochondrial pathway, caspase signaling, cAMP/PKA modulation, and Fas receptor activation, thereby promoting programed tumor cell death. Furthermore, GLPs act as potent immunomodulators by activating dendritic cells, T cells, B cells, and macrophages, reshaping the tumor immune microenvironment and strengthening anti-tumor immunity. GLPs have shown promising outcomes in clinical applications as adjuvant therapies to chemotherapy and radiotherapy, helping to alleviate treatment-related adverse events and improve patient outcomes. Their low toxicity and wide safety margins further support their clinical value.

Despite these advancements, challenges remain in translating GLPs into standardized and internationally recognized anti-cancer therapeutics. Major limitations include their structural complexity, heterogeneous composition, and the lack of well-defined structure-activity relationships. Differences in extraction sources, processing techniques, and molecular characterization lead to variable biological efficacy and hinder regulatory approval as well as global clinical acceptance. Moreover, most mechanistic evidence remains at the cellular level, with insufficient comprehensive molecular validation and clinical trial support. Therefore, future research should aim to establish standardized production and quality control methods, clarify precise molecular targets through advanced glycomics and bioinformatics technologies, and develop novel delivery strategies to improve bioavailability and tumor specificity. Well-designed, multicenter clinical trials are also essential to provide stronger evidence-based support.

In conclusion, GLPs represent a promising natural resource for cancer therapy owing to their multifaceted anti-tumor functions and excellent safety profile. Further interdisciplinary research integrating structural elucidation, mechanism-based optimization, and well-designed clinical studies is required to facilitate their translation into standardized and evidence-based anticancer therapeutics with broader clinical applicability.