Abstract
BACKGROUND:
The potential prognostic value of survivin is variably reported depending on the gastric cancer.
OBJECTIVE:
Evaluation of the prognostic and predictive significance of serum survivin and its relation with survival and treatment response rates in patients with locally advanced gastric cancer (LAGC).
METHODS:
Serum samples were prospectively collected from 50 patients with newly diagnosed LAGC. Serum samples of 32 healthy subjects were also collected as control groups for survivin levels. Serum survivin levels were evaluated at baseline and after three cycles of neoadjuvant chemotherapy in LAGC patients.
RESULTS
: Median survivin level was 147 IU/L (range
CONCLUSION:
It can be suggested that serum survivin can be used as a predictor of response to chemotherapy- but not survival- in LAGC patients receiving neoadjuvant mDCF chemotherapy. However, large multicenter prospective studies are required to confirm these results.
Introduction
The only approved curative therapy for locally advanced gastric cancer patients is radical surgical resection. Cure rates remain low even after wide surgical resection and 5-year survival is less than 25% [1]. Improved outcomes were obtained in patients treated with multimodality regimens including neoadjuvant, adjuvant chemotherapy, radiotherapy or chemo-radiotherapy in addition to surgical resection. In previous studies, neoadjuvant mDCF (modified Docetaxel- Cisplatin-Fluorouracil) chemotherapy regimen was shown to be efficient in locally advanced gastric cancer patients [2]. However, some patient groups show unfavorable disease course despite these therapies and thus there is a need for various predictive and prognostic factors. In this context, establishing predictive factors associated with treatment would allow optimization of patient selection and hence prolong expected survival.
Survivin is the smallest member of the inhibitor of apoptosis protein family (IAPs). Survivin gene which is located on the 17q25 chromosome consists of 3 introns and 4 exons and encodes a 142-amino acid protein [3, 4]. Survivin protein is involved in cell proliferation and angiogenesis in addition to anti-apoptotic activity [5]. It is expressed in G2/M phase of cell cycle to promote cell division [6]. Survivin is expressed in fetal tissues and in majority of tumors while it is expressed in negligible quantity in differentiated adult tissues [7, 8, 9]. Survivin was suggested to promote tumor growth and progression by inhibiting apoptosis and increasing cell proliferation [10]. Studies have reported that survivin is prognostic for various cancer [3, 11, 12, 13]. In a meta-analysis of gastric cancer, a relation between survivin expression levels and overall survival have been emphasized [14].
The aim of this study was to evaluate the relation of pre- and post-chemotherapy tumor survivin expression to therapeutic response and prognosis in patients with locally advanced gastric cancer who underwent surgery following neoadjuvant mDCF.
Patients and methods
Locally advanced gastric cancer patients who were admitted to SBU Ankara Numune Training and Research Hospital between September 2013 and June 2015 were included in this prospective study. Patients who had histopathologically proven gastric adenocarcinoma, those at clinically and radiologically confirmed locally advanced stage (regional lymph nodes measuring short axis
All patients received neoadjuvant chemotherapy with mDCF regimen [mDCF; docetaxel 60 mg/m
All blood samples were obtained by venipuncture from the antecubital vein, between 8:00 AM and 9:00 AM, and following overnight fasting after 8–10 hours. The plasma was separated by centrifuging at 2500 rpm for 20 min at room temperature, within 30 minutes of blood collection. The human survivin enzyme linked immunosorbent assay (ELISA) kit (Elabscience Biotechnology Co., Ltd, PRC; Catalog No: E-EL-H1584) was used for the quantitative determination of survivin in serum. The kit uses Sandwich-ELISA as the method. The micro ELISA plate provided in this kit has been pre-coated with an antibody specific to survivin. Standards or samples are added to appropriate micro ELISA plate wells and combined with the specific antibody. Then a biotinylated detection antibody specific for Survand Avidin- Horseradish Peroxidase (HRP) conjugate is added to each microplate well and incubated. Free components are washed away. And substrate solution is added. After a short incubation, the enzyme reaction is stopped and the color generated is read at 450 nm by an automed ELISA reader (BioTek, Elx800 Chemistry Analyzer). The measured optical density is directly proportional to the concentration of survivin in either standards or samples.
Baseline characteristics of the study subjects
Baseline characteristics of the study subjects
ECOG: Eastern Cooperative Oncology Group, CEA: Carcinoembryonic Antigen, CA19-9: Carbohydrate Antigen 19-9, PNI: Perineural invasion, LVI: Lymphovascular invasion.
Statistical analyses were performed using SPSS software version 22. Inc., Chicago, IL, USA). Data were presented as mean
Results
A total of 50 locally advanced gastric cancer patients (one patient was excluded due to early operation) and 32 healthy subjects were included. Baseline demographic and tumor characteristics of the patients are presented in Table 1. Mean age was 55 (range
All patients received 3 cycles of neoadjuvant mDCF chemotherapy. According to response evaluation performed after 3 cycles of therapy, complete response was not obtained in any of the gastric cancer patients; 42% showed partial response (PR), 38% had stable disease (SD) and 20% showed progression. Total gastrectomy was performed in 70% of patients, and 30% underwent subtotal gastrectomy after neoadjuvant chemotherapy. Only 4 (16%) patients had R1 resection. Adjuvant chemotherapy and chemo-radiotherapy was given to 48% and 62% of patients, respectively.
Median serum survivin levels were 147 (minimum
Association among baseline plasma survivin level and pathological features
Association among baseline plasma survivin level and pathological features
Relation between overall clinical response and survivin after neoadjuvant chemotherapy
PR: Partial response, SD: Stabil disease, PD: Progressive disease, (
Relation between overall response rate and survivin after neoadjuvant chemotherapy
PR: Partial response, SD: Stabil disease, PD: Progressive disease, (
Clinical response to mDCF regimen was classified as progressive (progressive disease) and non-progressive groups (partial response
On the other hand, survivin levels were significantly reduced after chemotherapy in patients who had partial response to neoadjuvant chemotherapy (
Median DFS was 12.4 and 14.6 months for low and high groups, respectively (log rank
Serum survivin levels changes in patients with or without clinical response.
Kaplan-Meier survival curves regarding to plasma survivin.
In this study, as a remarkable finding, declining serum survivin levels after neoadjuvant DCF chemo- therapy regimen was related to favorable response in patients with locally advanced gastric cancer. We also observed that patients who progressed after neoadjuvant therapy significantly had higher serum survivin levels compared to baseline serum survivin levels. No significant differences in any demographic or clinic-pathological characteristic were observed between patients with high as compared to low tumor survivin expression.
Survivin inhibits apoptosis directly or indirectly through inhibition of inducing (caspase-9) and effector (caspase-3 and caspase-7) caspases. Overexpression of survivin has been reported in almost all malignancies in humans including liver, pancreas, stomach, breast, esophagus, colon, over, lungs and hematological malignancies [16, 17, 18, 19]. Increased survivin mRNA and protein levels in gastric cancer have been shown to play a role in the development of gastric cancer [20]. Survivin protein cannot be detected in normal gastric mucosa and its mRNA is low. In our study, concordant with tissue survivin levels, increased serum survivin levels were found in gastric cancer patients compared to healthy subjects (
Many studies and meta-analyses have been published associated with prognostic value of survivin in gastric cancer patients. In their study, Wang et al. have reported that survivin values were associated with more aggressive tumor biology, higher disease recurrence and shorter survival [21]. According to the meta-analysis by Krieg et al., survivin expression did not show statistically significant association with gender, depth of invasion, stage, grade of differentiation, histological type, distant metastases, lymphatic or blood vessel invasion and perineural invasion, while it was found significantly associated with lymph node metastasis and overall poor survival [14]. The meta-analysis of 16 studies, conducted by Liu et al., has reported that survivin expression (particularly cytoplasmic expression) was associated with poor overall survival [22]. In contrast to the above mentioned studies indicating poor prognostic features, there are studies showing survivin expression is not a negative prognostic factor [23, 24]. Vallböhmer et al. have found that cytoplasmic overexpression of survivin in locally advanced gastric cancer patients receiving neoadjuvant chemotherapy (cisplatin, 5-fluorouracil, leucovorin) was associated with longer overall survival [23]. Based on multivariate analysis, Okada et al. have reported that nuclear survivin expression of tumor tissue was associated with favorable prognosis while cytoplasmic survivin expression was not associated with prognosis [24]. Survivin expression was also shown not to have negative prognostic effect in breast, bladder, esophagus cancers or osteosarcoma besides gastric cancers [25, 26, 27, 28]. Similarly, in our study no statistical association was found between serum survivin values and recurrence or survival. Different results in our study and other studies might be related to lack of subcellular located survivin evaluation (due to different prognostic values of nuclear vs cytoplasmic survivin), statistical bias resulting from small sample size of the studies, different methods of evaluation (immune-histochemical, RT-PCR), heterogeneity of patient groups (early stage, locally advanced), methodological differences and evaluation based on different specimens (blood vs tissue).
Approximately 15 years ago, Ikeguchi and colleagues have detected a relation between survivin expression of gastric cancer cells and chemotherapy. These studies have reported that survivin expression could be an indicator for chemo-resistance of malignant cells [29, 30]. The study by Meng et al. have investigated the relation between survivin variant expression in gastric cancer tissue and chemo-resistance (gemcitabine, fluorouracil, cisplatin and docetaxel) and found chemo-resistance relation only between docetaxel and survivin variant (wild-type variant) [31]. A subsequent study by Meng et al. have reported chemotherapy response relation between wild type survivin variant mRNA levels and docetaxel [32]. In a study conducted with esophagus cancer patients, Beardsmore et al. have detected significant relation between survivin expression and proliferation index in locally advanced esophagus cancer patients receiving neoadjuvant chemo-radiotherapy and suggested that survivin expression can be associated with pathological complete response to neoadjuvant chemo-radiotherapy [33]. Additionally, nuclear survivin overexpression was found associated with favorable clinical response in advanced stage non-small cell lung cancer patients receiving taxan/platin [34]. The majority of the above mentioned studies were conducted with single chemotherapy agent, evaluated survivin expression of cancer tissue cells and primarily described survivin variant or survivin subclassification (mitochondrial or nuclear). Our study is unique compared to previous studies, being the first to evaluate serum survivin in patients receiving triple chemotherapy regimen and in our study, survivin levels were significantly reduced (
Limitations of our study were being a single-center study, inability to perform multivariate analysis due to limited number of patients and lack of information about the correlation between positive serum survivin and survivin expression of tumor tissue. Another limitation is evaluation of survivin in patients received only 3 cycles (not 1–2 cycles) of neoadjuvant mDCF chemotherapy.
Conclusion
It can be suggested that survivin can be used as a predictor of response to chemotherapy- but not survival- in locally advanced gastric cancer patients receiving neoadjuvant mDCF chemotherapy. However, large multicenter prospective studies are required to confirm these results.
Footnotes
Acknowledgments
The authors declare that they have no conflict of interest. The authors have received no payment in preparation of this manuscript.
