Abstract
Abstract
Background:
Vascular endothelial growth factor (VEGF) is a crucial regulator of physiological and pathological angiogenesis. Increased VEGF expression has been linked with inappropriate VEGF-induced angiogenesis in various disease pathologies including cancers.
Methodology:
In this case–control study, DNA samples of 319 esophageal squamous cell cancer (ESCC) patients and 354 healthy controls from Punjab, North-West India, were screened for VEGF-417T/C, -172C/A, -165C/T, -160C/T, -152G/A, -141A/C, and -116G/A promoter polymorphisms using Sanger sequencing.
Results:
AA genotype and A allele of both VEGF-152G/A and -116G/A polymorphisms were significantly associated with elevated risk to ESCC in total subjects as well as in female group. CT genotype and T allele of VEGF-165C/T polymorphism were significantly associated with reduced risk for ESCC only in female group. Body mass index-based stratification analysis revealed significant association of AA genotype and A allele of VEGF-152G/A and A allele of VEGF-116G/A polymorphism with an increased risk to ESCC in nonobese patients. Linkage disequilibrium was observed between VEGF-165C/T and VEGF-141A/C (D′ = 0.88, r2 = 0.68) and between VEGF-152G/A and VEGF-116G/A (D′ = 0.93, r2 = 0.49) polymorphisms. Haplotype T-C-C-C-A-A-A was significantly associated with increased ESCC risk in total subjects as well as in female group.
Conclusion:
From this study, we concluded that VEGF-116 G/A and VEGF-152G/A polymorphisms were significantly associated with increased ESCC risk in total patients as well as in female group, whereas VEGF-165 C/T polymorphism was associated with reduced risk only in female group.
Introduction
Vascular endothelial growth factor (VEGF) is a paradigm of gene regulation as it is regulated at all stages of gene expression, including transcription, messenger RNA (mRNA) stability, and mRNA translation.1,2 The VEGF, a highly conserved homodimeric glycoprotein, is a crucial regulator of physiological and pathological angiogenesis.3 Increased VEGF expression has been linked with inappropriate VEGF-induced angiogenesis in various disease pathologies, including tumor growth and metastasis.4 It has been demonstrated that patients with a low VEGF expression have a better prognosis as compared to those with high expression levels.5,6
VEGF or VEGFA (OMIM 192240) located at 6p21.1 spanning the 14 kb coding region7 is a highly polymorphic gene, and more than 30 single nucleotide polymorphisms (SNPs) have been reported in different parts of this gene.8,9 Functional polymorphisms in the VEGF promoter may influence promoter activity, resulting in differences in VEGF protein production between individuals.9–11
The role of VEGF-417T/C, -172C/A, -165C/T, -160C/T, -152G/A, -141A/C, and -116G/A promoter polymorphisms has been investigated in different diseases. Till date, there are only few reports on some of these seven polymorphisms in gastrointestinal tract (GIT) cancers. VEGF-116G/A polymorphism has been studied in various GIT cancers, such as oral,12,13 gastric,14 colon,15 colorectal,16–20 gallbladder,21 and hepatocellular cancer.22,23 VEGF-417T/C and VEGF-152G/A have been studied in colorectal cancer in the Japanese population.16 VEGF-141A/C has been studied in hepatocellular carcinoma in Turkish population.24 The association of A allele of VEGF-141A/C polymorphism with increased risk of papillary thyroid carcinoma has been reported in the Australian population.25 G allele of VEGF-152G/A has been reported to be associated with increased risk of nonsmall cell lung cancer in North Indians.26
Correlation of VEGF promoter polymorphisms with therapy response has been studied in different GIT cancers. A allele of VEGF-116G/A polymorphism has been reported to be associated with severe acute toxicities in 5-fluorouracil/cisplatin-based chemoradiotherapy-treated Japanese esophageal cancer patients.27 GG genotype of VEGF-152G/A and VEGF-116G/A polymorphism wasassociated with shorter progression-free survival inmetastatic colorectal cancer patients.28 In Dutch population, VEGF-116AA genotype was associated withshorter progression-free survival in gastrointestinal stromal tumor patients treated with Imatinib based therapy.29 In metastatic colorectal cancer, GG genotype of VEGF-116 G/A polymorphism was reported with better response rates to chemotherapy and longer progression-free survival.30 Variations in the VEGF could have a promising role in identifying different risk categories among patients receiving anti-angiogenic therapies.
VEGF is a key mediator of continued survival and progression in solid tumors, including esophageal cancer.31 Some studies documented the involvement of VEGF-induced angiogenesis in esophageal adenocarcinoma.32–36 Over expression of VEGF has been reported to be linked with poor clinical outcomes in patients with advanced esophageal squamous cell carcinoma.37–41
Genetic polymorphisms might be responsible for interindividual differences in esophageal cancer susceptibility and progression.42 The prognostic significance of VEGF SNPs in esophageal cancer has been reported in Caucasians.43 Till date, there is only one published study among GIT cancers from North India, which reported an increased cancer risk associated with VEGF-116 A allele.21 VEGF promoter polymorphisms have been linked with GIT cancer risk and its development, prognosis, and therapy response; therefore, the aim of this present study was to investigate the role of seven VEGF promoter polymorphisms [-417T/C (rs833062), -172C/A (rs59260042), -165C/T (rs79469752), -160C/T, -152G/A (rs13207351), -141A/C (rs28357093), and -116G/A (rs1570360)] with esophageal squamous cell cancer risk in North-West Indians. To the best of our knowledge, this is the first study on these seven VEGF promoter polymorphisms in esophageal squamous cell cancer.
Materials and Methods
Selection of study participants and collection of blood samples
We conducted a case–control study on 673 subjects (319 esophageal squamous cell cancer (ESCC) patients and 354 controls). The design of this study was approved by the institutional ethics committee of Guru Nanak Dev University, Amritsar. All methods were carried out in accordance with relevant guidelines and regulations (IRB approval No. 1610/HG, dated May 9, 2023). Clinically confirmed ESCC patients were recruited from Sri Guru Ram Das Institute of Medical Sciences and Research, Vallah, Amritsar, Punjab (India). The control group consisted of 354 unrelated healthy, age-, gender-, and geography-matched individuals. The demographic and clinical characteristics of ESCC patients and controls were recorded on proforma. All the patients and controls gave a written informed consent to participate in this study. Five milliliter venous blood sample was collected from each subject in an ethylene diamine tetra-acetic acid (EDTA)-coated vial and was stored at −20 °C for subsequent DNA extraction. Genomic DNA was extracted from each blood sample using the standard method.44
Genotyping of VEGF promoter polymorphisms
The promoter region of VEGF (Fig.1) harboring sevenpolymorphisms [-417T/C (rs833062), -172C/A (rs59260042), -165C/T (rs79469752), -160C/T, -152G/A (rs13207351), -141A/C (rs28357093), and -116G/A (rs1570360)] was amplified using published primer sequences.45 The polymerase-chain reaction (PCR) reaction of 25 µl contained 100 ng of genomic DNA, 1X Taq buffer, 0.5 µl dNTPs mix, 10 pmol of forward and reverse primers, 1X Q-solution, and 0.6U Taq polymerase (Qiagen, Germany). Amplification conditions consisted of initial denaturation at 95 °C for 5 min, followed by 35 cycles with denaturation at 95 °C for 45 s, annealing at 62 °C for 30 s, extension at 72 °C for 45 s, and final extension at 72 °C for 10 min. The purified PCR products of 486bp were sequenced using the Big Dye terminator kit (version 3.1). Sequencing data were analyzed using Chromas v1.45 (Technelysium Pty Ltd., Queensland, Australia) software.

Diagram showing locations of analyzed VEGF promoter polymorphisms.
Statistical analysis
Deviation of genotype frequencies from Hardy–Weinberg equilibrium was assessed using chi square test. Odds ratio (OR) and its 95% confidence interval (CI) were used to find the association of genotypes and alleles of VEGF polymorphisms with ESCC risk. The age, gender, diet, smoking status, and alcohol consumption were selected as adjustment variables. Data analysis was carried out using online SNPstats software.46 Online SHEsis software was used to calculate Lewontin’s standardized disequilibrium coefficient (D′) and correlation coefficient (r2).47 The value of p < 0.05 was considered statistically significant.
Results
Characteristics of the ESCC patients and healthy controls
In this case–control study, a total of 673 subjects (319 ESCC patients and 354 unrelated healthy controls) from the Punjab state, North-West India, were screened (Table1). The mean age of patients and controls was 56.59 ± 13.02 and 56.01 ± 12.23 years, respectively. In 62.07% of patients, cancer was diagnosed after the age of 50 years. The number of female patients was higher as compared to male patients. Of the 319 ESCC patients, 12.56% had stage I, 44.72% had stage II, 25.63% had stage III, and 9.05% had stage IV tumor. Cancer stage was unknown in 8.04% patients.
Baseline characteristics of ESCC patients and healthy controls
ESCC: esophageal squamous cell cancer.
Association of VEGF promoter polymorphisms with ESCC risk in total patients
The DNA samples of 319 ESCC patients and 354 controls were screened for VEGF-417T/C, -172C/A, -165C/T, -160C/T, -152G/A, -141A/C, and -116G/A VEGF promoter polymorphisms using Sanger sequencing. We observed 2bp ins/del in seven esophageal cancer patients and in one healthy control. The genotypes distributions of VEGF-116 G/A and VEGF-152G/A polymorphisms were in agreement with Hardy–Weinberg equilibrium in controls (p > 0.05). Comparative genotype and allele frequencies of VEGF promoter polymorphisms between ESCC patients and controls have been detailed in Table2. The frequency of AA genotype and A allele of VEGF-152G/A andVEGF-116G/A polymorphisms was higher in ESCC patients as compared to controls. Individuals with VEGF-152AA genotype (OR = 1.78, 95% CI, 1.12–2.82; p = 0.04) and A allele (OR = 1.30, 95% CI, 1.05–1.62; p = 0.02) showed significantly increased risk to esophageal cancer in total subjects. Genetic model analysis of VEGF-152G/A polymorphism revealed significantly increased cancer risk under codominant (p = 0.04), recessive (p = 0.02), and log additive (p = 0.02) genetic models (Table3).
The relationship between VEGFA promoter polymorphisms and susceptibility to esophageal squamous cell carcinoma
AOR: adjusted odds ratio; CI: confidence interval.
Adjusted for age, gender, diet, smoking status, and alcohol consumption.
Adjusted for age, diet, smoking status, and alcohol consumption; statistically significant p values are displayed in bold.
Association of VEGF-152G/A and
AOR: adjusted odds ratio; CI: confidence interval; ESCC: esophageal squamous cell cancer.
Adjusted for age, gender, diet, smoking status and alcohol consumption;
Adjusted for age, diet, smoking status, and alcohol consumption; statistically significant p values are displayed in bold.
VEGF-116AA genotype (OR = 2.71, 95% CI, 1.52–4.83; p = 0.002) and A allele (OR = 1.47, 95% CI, 1.16–1.86; p = 0.001) were significantly associated with increased risk for esophageal cancer (Table2). Genetic model analysis of VEGF-116G/A polymorphism showed significantly increased cancer risk under codominant (p= 0.002), dominant (p = 0.02), recessive (p = 0.001), and log additive (p = 0.001) model (Table3). No significant association was found between VEGF-417T/C, VEGF-172C/A, VEGF-165C/T, VEGF-160C/T, and VEGF-141A/C polymorphisms and esophageal cancer risk in the studied population (p > 0.05).
Gender wise stratification of VEGF promoter polymorphisms and ESCC risk
Stratification of data of VEGF polymorphisms showed a gender-specific association (Table2). In the female group, individuals carrying VEGF-152AA genotype (p = 0.005) and A allele (p = 0.003) had significantly increased risk of esophageal cancer. Similarly, female patients with VEGF-116 AA genotype (p = 0.008) and A allele (p = 0.007) showed increased risk of esophageal cancer. CT genotype (p = 0.03) and T allele (p = 0.03) of VEGF-165C/T polymorphism were significantly associated with reduced risk for esophageal cancer in the female group. Genetic model analysis revealed an association of VEGF-152G/A polymorphism with increased risk under codominant (p = 0.005), recessive (p = 0.002), and log additive model (p = 0.003) in the female group (Table3). VEGF-116G/A polymorphism was also associated with increased risk of esophageal cancer under codominant (p = 0.008), recessive (p = 0.002), and log additive model (p = 0.01) in the female group (Table3).
Age wise stratification of VEGF promoter polymorphisms and ESCC risk
We investigated the association of VEGF polymorphisms with the age at diagnosis of the patients and found that A allele (p = 0.04) of VEGF-116G/A polymorphism was significantly associated with increased risk of esophageal cancer in patients having age at diagnosis more than 50 years as compared to patients having age at diagnosis less than 50 years (
Stratification of the data based on body mass index
It was observed that the AA genotype (p = 0.007) and Aallele (p = 0.01) of VEGF-152G/A and A allele (p = 0.006) of VEGF-116G/A polymorphism were significantly associated with increased risk to esophageal cancer in nonobese patients (
Genotype combinations of VEGF promoter polymorphisms and ESCC risk
We compared the different genotype combinations of studied polymorphisms and found that TT-AA (p = 0.03) genotype combination of VEGF-417T/C and VEGF-152G/A, TT-AA (p = 0.002) of VEGF-417T/C and VEGF-116G/A, CC-AA (p = 0.02) of VEGF-165C/T and VEGF-152G/A, CC-AA (p = 0.0006) of VEGF-165C/T and VEGF-116G/A, CC-AA (p = 0.02) of VEGF-160C/T and VEGF-152G/A, CC-AA (p = 0.0005) of VEGF-160C/T and VEGF-116G/A, AA-AA (p = 0.02) of VEGF-152G/A and VEGF-141A/C, AA-AA (p= 0.002) of VEGF-152G/A and VEGF-116G/A, and AA-AA (p = 0.0007) of VEGF-141A/C and VEGF-116G/A polymorphisms were significantly associated with increased risk to esophageal cancer (
Linkage disequilibrium and haplotype analysis
Linkage disequilibrium (LD) analysis of VEGF promoter polymorphisms revealed a LD between VEGF-165C/T and VEGF-141A/C (D′ = 0.88, r2= 0.68) and between VEGF-152G/A and VEGF-116G/A (D′ = 0.93, r2 = 0.49) polymorphisms (Fig.2). Haplotype analysis was carried out to evaluate the combined effect of VEGF promoter polymorphisms on ESCC risk. T-C-C-C-G-A-G was the most common haplotype in the present study with the frequencies of 45.6% in ESCC patients and 49.5% in healthy controls. Haplotype T-C-C-C-A-A-A was significantly associated with increased ESCC risk in total subjects (p = 0.01) as well as in female group (p = 0.02) (Table4). No significant association between other VEGF haplotypes and ESCC risk was observed.

Linkage disequilibrium pattern for VEGF promoter polymorphisms in ESCC patients based on (A) D′ and (B) r2; SNP1: VEGF-417T/C, SNP2: VEGF-172C/A, SNP3: VEGF-165C/T, SNP4: VEGF-160C/T, SNP5: -152G/A, SNP6: VEGF-141A/C and SNP7: VEGF-116G/A.
VEGF haplotypes and ESCC risk
AOR: adjusted odds ratio; CI: confidence interval; ESCC: esophageal squamous cell cancer.
In the order of VEGF-417T/C,-172C/A,-165C/T,-160C/T,-152G/A,-141A/C,-116G/A.
Adjusted for age, gender, diet, smoking status and alcohol consumption.
Adjusted for age, diet, smoking status and alcohol consumption statistically significant p values are displayed in bold.
Discussion
In the present case–control study, we investigated whether VEGF-417T/C, -172C/A, -165C/T, -160C/T, -152G/A, -141A/C, and -116G/A promoter polymorphisms are associated with ESCC risk in the North-West Indians. Till now, there is no published study on these seven polymorphisms in esophageal squamous cell cancer. There are very limited studies in different ethnic groups reporting the association of these seven VEGF promoter polymorphisms with GIT cancers (
Key findings of VEGF promoter polymorphisms in ESCC, breast, gall bladder, and nonsmall cell lung cancer patients in North Indians
ESCC: esophageal squamous cell cancer.
In this study, we found that VEGF-116 AA genotype (p = 0.002) and A allele (p = 0.001) were significantly associated with an increased risk of ESCC. The A allele of VEGF-116 G/A polymorphism has been reported to be associated with lower VEGF plasma levels as compared to the G allele.8,49 The findings of the present study are consistent with reports on some GIT cancers (
Similarly, VEGF-152 AA genotype (p = 0.04) and A allele (p = 0.02) were significantly associated with increased esophageal cancer risk in the present study. There are very few studies reporting the association of VEGF-152G/A polymorphism with cancer. The association of VEGF-152GA and AA genotypes with higher VEGF mRNA levels has been reported in Japanese colorectal cancer patients.16 AA genotype of VEGF-152G/A polymorphism was associated with larger tumor size and poor overall survival in Korean hepatocellular patients.50
We did not observe any significant association of VEGF-417T/C, -172C/A, -165C/T, -160C/T, and -141A/C polymorphisms with ESCC. No association of VEGF-417T/C polymorphism with risk to colorectal cancer was observed in the Japanese patients.16 It has been predicted that VEGF-172A allele abolished the binding site of Sp1 transcription factor and created the binding of GATA-1 and GATA-2 transcription factors.48 Sp1 is a zinc finger transcription factor that binds to variety of gene promoters containing GC-rich motifs52 and has also been implicated in apoptosis.53 In the mouse model, it has been demonstrated that the GATA family members help in regulation of gene expression in hematopoietic cells.54 Hematopoietic cells are involved in tumor angiogenesis and regulate the angiogenic switch during tumorigenesis.55 No significant risk association of VEGF-141 A/C was reported in the present study. VEGF-141 A/C polymorphism was not associated with hepatocellular carcinoma in Turkish patients.24 The association of VEGF-141 A allele with increased risk to papillary thyroid carcinoma has been documented in Australian females.25 Our results on VEGF-417T/C, -172C/A, -165C/T, -160C/T, -152G/A, and -141A/C polymorphisms are concordant with other studies on other diseases apart from cancers (Table6).
Published studies on the association of VEGF-417T/C, -172C/A, -165C/T, -160C/T, -152G/A, and -141A/C promoter polymorphisms with different diseases
In this study, a significant association of VEGF-152AA genotype (p = 0.005) and A allele (p = 0.003) and VEGF-116 AA genotype (p = 0.008) and A allele (p= 0.007) with increased risk of esophageal cancer was reported in the female subjects. CT genotype (p = 0.03) and T allele (p = 0.03) of VEGF-165C/T polymorphism were significantly associated with reduced risk for esophageal cancer in the female group. Similarly, we reported the association of AA genotype and A allele of VEGF-152G/A polymorphism and AA genotype and A allele of VEGF-116G/A polymorphism with increased risk of breast cancer, whereas CT genotype and T allele of VEGF-165 C/T polymorphism were associated with decreased risk of breast cancer in our previous study (Table5). Higher serum VEGF levels were reported in females as compared to the males in the Greek population.71 High estrogen levels in the female subjects might influence higher VEGF protein production, thus enhanced angiogenesis in the females.72,73
Body mass index (BMI)-based stratification analysis revealed significant association of AA genotype (p = 0.007) and A allele (p = 0.01) of VEGF-152G/A and A allele (p = 0.006) of VEGF-116G/A polymorphism with an increased risk to esophageal cancer in nonobese patients (
A LD was observed between VEGF-165C/T and VEGF-141A/C (D′ = 0.88, r2 = 0.68) and between VEGF-152G/A and VEGF-116G/A (D′ = 0.93, r2 = 0.49) polymorphisms in the present study. Strong LD between VEGF-165C/T and -141A/C polymorphisms (D′ = 1.0, r2 = 0.70) has been reported in our previous study on breast cancer patients from the same population (Table5). Haplotype analysis is a better approach for the prediction of disease risk as compared to single/double or the triple polymorphism approach. In the present study, T-C-C-C-A-A-A haplotype of VEGF-417T/C, -172C/A, -165C/T, -160C/T, -152G/A, -141A/C, and -116G/A polymorphisms was significantly associated with increased ESCC risk in the total patients (p = 0.01) as well as in the female group 6 (p = 0.02). The association of VEGF-2578C/-165C/-152G/-141A/-116G/-634C/-7C/+936C haplotype with smaller tumor size has been reported in Korean hepatocellular carcinoma patients.50 Apart from cancers, significant association ofhaplotype T-T-C-C-C-G-A-A-C of VEGF-460T/C, -417T/C, -172C/A, -165T/C, -160C/T, -152G/A, -141A/C, -116G/A, and +405G/C polymorphisms with increased susceptibility to develop age-related macular degeneration has been reported in Europeans.56 In other study, haplotype C-T-C-C-C-A-A-A-C of VEGF-460T/C, -417T/C, -172C/A, -165T/C, -160C/T, -152G/A, -141A/C, -116G/A, and +405G/C was significantly associated with Type 1 or 2 diabetes with proliferative diabetic retinopathy, whereas haplotype C-T-C-C-C-A-A-G-G was significantly associated with Type 1 or 2 diabetes without retinopathy in Europeans.45
Till date, nine genome-wide association studies have been conducted in ESCC and identified several disease susceptibility loci on different chromosomes (
The correlation of VEGF-417T/C, -165C/T, -152G/A, -141A/C, and -116G/A promoter polymorphisms with response to different therapy regimens has been studied in GIT cancers (
Conclusions
This study findings concluded that VEGF-116 G/A and VEGF-152G/A polymorphisms were significantly associated with increased ESCC risk in total patients as well as in the female group, whereas VEGF-165 C/T polymorphism was associated with reduced risk only in the female group.
Footnotes
References
Supplementary Material
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