Common Genetic Variants of PSCA, MUC1 and PLCE1 Genes are not Associated with Colorectal Cancer

Significance of PSCA as a novel prognostic marker and therapeutic target for cancer

One of the contributing factors in the diagnosis and treatment of most cancers is the identification of their surface antigens. Cancer tissues or cells have their specific antigens. Some antigens that are present in many cancers elicit different functions. One of these antigens is the prostate stem cell antigen (PSCA) antigen, which was first identified in the prostate. PSCA is a cell surface protein that has different functions in different tissues. It can play an inhibitory role in cell proliferation as well as a tumor-inducing role. PSCA has several genetic variants involved in cancer susceptibility in some tissues, so identifying the characteristics of this antigen and its relationship with clinical features can provide more information on diagnosis and treatment of patients with cancers. Most studies on the PSCA have focused on prostate cancer. While it is also expressed in other cancers, little attention has been paid to its role as a valuable diagnostic, prognostic, and therapeutic tool in other cancers. PSCA has several genetic variants that seem to play a significant role in cancer susceptibility in some tissues, so identifying the characteristics of this antigen and its relationship and variants with clinical features can be beneficial in concomitant cancer therapy and diagnosis, as theranostic tools. In this study, we will review the alteration of the PSCA expression and its polymorphisms and evaluate its clinical and theranostics significance in various cancers.

The PSCA rs2294008 (C/T) Polymorphism Increases the Risk of Gastric and Bladder Cancer: A Meta-Analysis

Background: It has been reported that prostate stem cell antigen (PSCA) is overexpressed in certain cancer types and confers poor prognoses. The rs2294008 (C/T) polymorphism of PSCA is considered to be associated with risk for gastric, bladder, and colorectal cancers; however, these studies have produced inconsistent results, so we performed this meta-analysis to verify the association between the PSCA rs2294008 (C/T) polymorphism and cancer risk. Methods: A systematic literature search was performed using PubMed, EMBASE, and the Chinese National Knowledge Infrastructure, through October 20, 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association between the PSCA rs2294008 (C/T) polymorphism and cancer risk. In addition, we explored PSCA mRNA expression in cancers through online databases. Results: In total, 45 articles met our inclusion criteria and were analyzed, including 37,586 cancer cases and 51,197 non-cancer controls. Except in the recessive model, the pooled effect indicated the PSCA rs2294008 T allele was associated with an increased overall cancer risk (T vs. C: OR = 1.120, 95% CI = 1.056-1.188, p < 0.01; TT vs. CC: OR = 1.206, 95% CI = 1.066-1.364, p = 0.03; CT vs. CC: OR = 1.249, 95% CI = 1.151-1.356, p < 0.01; [CT+TT] vs. CC: OR = 1.248, 95% CI = 1.147-1.359, p < 0.01; TT vs. [CT+CC]: OR = 1.051, 95% CI = 0.954-1.156, p = 0.314). In the subgroup analysis, there were significant associations between the rs2294008 T allele and increased risk of bladder and gastric cancer. Two different online tools were used to explore the PSCA mRNA levels in cancer and the corresponding normal adjacent tissues. We found that expression of PSCA was significantly lower in gastric cancer patients. Conclusions: The PSCA rs2294008 T polymorphism is related to increased cancer susceptibility, especially for gastric and bladder cancers. This polymorphism results in a decreased PSCA expression level in gastric cancer.

Role of Genetic Polymorphisms of Cytochrome P450 2C19 in Pantoprazole Metabolism and Pantoprazole-based Helicobacter pylori Eradication Regimens

BACKGROUND

Cytochrome P450 (CYP450) enzymes play an important role in the metabolism of 70-80% of the currently used medications, including proton pump inhibitors. There are some data analyzing the impact of gene polymorphisms of CYP450 enzymes on most widely used PPIs, such as omeprazole, however, the data on pantoprazole are highly lacking.

OBJECTIVE

To summarize the most recent publications and studies on the role of polymorphisms of the genes encoding CYP450 enzyme 2C19 in the metabolism of pantoprazole and pantoprazole based Helicobacter pylori eradication regimens.

METHODS

We performed a non-systematic search of the available literature on the selected topic.

RESULTS AND CONCLUSION

The data on cytochrome P450 gene polymorphisms and their role in pantoprazole metabolism and pantoprazole based Helicobacter pylori eradication remain conflicting. Individual differences in pantoprazole metabolism might be partly related to genetic polymorphisms of CYP450 enzymes. Most of the studies support the observation that cytochrome 2C19 polymorphisms have an impact on the pharmacokinetics of pantoprazole and its therapeutic effects: poor metabolizers of PPIs are more likely to have a better response to pantoprazole therapy and achieve better H. pylori eradication rates compared to rapid metabolizers. The determination of alleles that are associated with decreased (e.g., *2, *3 alleles) or increased (e.g., *17 allele) cytochrome 2C19 enzyme activity might be used as predictive factors for the potential of acid suppression and the success of Helicobacter pylori eradication. Overall, currently available data do not provide robust evidence, therefore, the application of genetic polymorphisms of cytochrome enzymes in clinical practice still cannot be recommended as routine practice for personalized pantoprazole prescription strategies.

The Role of VEGFA, COX2, HUR and CUGBP2 in Predicting the Response to Neoadjuvant Therapy in Rectal Cancer Patients

Background and objectives: The effectiveness of neoadjuvant therapy, which is commonly used for stage II-III rectal cancer (RC) treatment, is limited. Genes associated with the pathogenesis of RC could determine response to this treatment. Therefore, the aim of this study was to investigate the potential predictive value of VEGFA, COX2, HUR and CUGBP2 genes and the associations between post-treatment changes in gene expression and the efficacy of neoadjuvant therapy. Materials and Methods: Biopsies from RC and healthy rectal tissue of 28 RC patients were collected before neoadjuvant therapy and 6-8 weeks after neoadjuvant therapy. The expression levels of VEGFA, COX2, HUR, CUGBP2 genes were evaluated using a quantitative real-time polymerase chain reaction. Results: The results reveal a significantly higher expression of VEGFA, COX2 and HUR mRNA in RC tissue compared to healthy rectal tissue (p < 0.05), and elevated VEGFA gene expression in pre-treatment tissues was associated with a better response to neoadjuvant therapy based on T-stage downstaging (p < 0.05). The expression of VEGFA, HUR and CUGBP2 genes significantly decreased after neoadjuvant therapy (p < 0.05). Responders to treatment demonstrated a significantly stronger decrease of VEGFA and COX2 expression after neoadjuvant therapy than non-responders (p < 0.05). Conclusions: The findings of this study suggest that the pre-treatment VEGFA gene expression might have predictive value for the response to neoadjuvant therapy, while the post-treatment decrease in VEGFA and COX2 gene expression could indicate the effectiveness of neoadjuvant therapy in RC patients.

Common variation in FAM155A is associated with diverticulitis but not diverticulosis

Colonic diverticulosis is a very common condition. Many patients develop diverticulitis or other complications of diverticular disease. Recent genome-wide association studies (GWAS) consistently identified three major genetic susceptibility factors for both conditions, but did not discriminate diverticulititis and diverticulosis in particular due the limitations of registry-based approaches. Here, we aimed to confirm the role of the identified variants for diverticulosis and diverticulitis, respectively, within a well-phenotyped cohort of patients who underwent colonoscopy. Risk variants rs4662344 in Rho GTPase-activating protein 15 (ARHGAP15), rs7609897 in collagen-like tail subunit of asymmetric acetylcholinesterase (COLQ) and rs67153654 in family with sequence similarity 155 A (FAM155A) were genotyped in 1,332 patients. Diverticulosis was assessed by colonoscopy, and diverticulitis by imaging, clinical symptoms and inflammatory markers. Risk of diverticulosis and diverticulitis was analyzed in regression models adjusted for cofactors. Overall, the variant in FAM155A was associated with diverticulitis, but not diverticulosis, when controlling for age, BMI, alcohol consumption, and smoking status (OR_adjusted 0.49 [95% CI 0.27–0.89], p = 0.002). Our results contribute to the assessment specific genetic variants identified in GWAS in the predisposition to the development of diverticulitis in patients with diverticulosis.

Variants in the PSCA gene associated with risk of cancer and nonneoplastic diseases: systematic research synopsis, meta-analysis and epidemiological evidence

Variants in the prostate stem cell antigen (PSCA) gene have been linked with risk of multiple cancers and other diseases. But results have been inconclusive and no systematic research synopsis has been available. We did a comprehensive meta-analysis to investigate associations between variants in this gene and risk of nine cancers and four nonneoplastic diseases based on data from 55 publications including 81 961 cases and 442 932 controls. We graded levels of cumulative epidemiological evidence of a significant association using the Venice criteria and false-positive report probability tests. We performed functional annotation for these variants using data from the Encyclopedia of DNA Elements Project and other public databases. We found that six variants were nominally significantly associated with an increased or reduced risk of three cancers and three nonneoplastic diseases (P < 0.05). Cumulative evidence of an association was graded as strong for rs2294008 [odds ratio (OR) = 1.32, P = 5.1 × 10-33], rs2976392 (OR = 1.29, P = 1.8 × 10-8), rs9297976 (OR = 0.75, P = 1.4 × 10-7), rs2976391 (OR = 1.38, P = 6.1 × 10-5) and rs138377917 (OR = 0.53, P = 0.008) with gastric cancer, rs2294008 with bladder cancer (OR = 1.15, P = 8.0 × 10-19), gastritis (OR = 1.35, P = 1.2 × 10-5), duodenal ulcer (OR = 0.68, P = 2.4 × 10-57) and gastric ulcer (OR = 0.88, P = 1.7 × 10-7). Data from the Encyclopedia of DNA Elements Project and other databases showed that these variants and other variants correlated with them might fall in putative functional regions. In conclusion, this study provides summary evidence that variants in the PSCA gene are associated with risk of gastric and bladder cancer, gastritis, as well as duodenal and gastric ulcer and highlights the significant role of this gene in the pathogenesis of these diseases.

Single nucleotide polymorphisms within MUC4 are associated with colorectal cancer survival

Mucins and their glycosylation have been suggested to play an important role in colorectal carcinogenesis. We examined potentially functional genetic variants in the mucin genes or genes involved in their glycosylation with respect to colorectal cancer (CRC) risk and clinical outcome. We genotyped 23 single nucleotide polymorphisms (SNPs) covering 123 SNPs through pairwise linkage disequilibrium (r2>0.80) in the MUC1, MUC2, MUC4, MUC5AC, MUC6, and B3GNT6 genes in a hospital-based case-control study of 1532 CRC cases and 1108 healthy controls from the Czech Republic. We also analyzed these SNPs in relation to overall survival and event-free survival in a subgroup of 672 patients. Among patients without distant metastasis at the time of diagnosis, two MUC4 SNPs, rs3107764 and rs842225, showed association with overall survival (HR 1.40, 95%CI 1.08-1.82, additive model, log-rank p = 0.004 and HR 0.64, 95%CI 0.42-0.99, recessive model, log-rank p = 0.01, respectively) and event-free survival (HR 1.31, 95%CI 1.03-1.68, log-rank p = 0.004 and HR 0.64, 95%CI 0.42-0.96, log-rank p = 0.006, respectively) after adjustment for age, sex and TNM stage. Our data suggest that genetic variation especially in the transmembrane mucin gene MUC4 may play a role in the survival of CRC and further studies are warranted.

Single Nucleotide Polymorphisms in PLCE1 for Cancer Risk of Different Types: A Meta-Analysis

Background: Recent studies have investigated the relationships between PLCE1 polymorphisms and cancer susceptibility. However, some findings lack consistency.

Objectives: In the current study, we conducted a meta-analysis to more accurately evaluate the relationships between PLCE1 (rs2274223, rs3765524, rs753724, rs11187842, and rs7922612) single nucleotide polymorphisms (SNPs) and risk for different types of cancer.

Methods: We performed a comprehensive search strategy in PubMed, Web of Science, Medline, EMbase, and Scopus for articles available until 19 March 2018. A total of 54 case-control studies comprising 17,955 cases and 20,400 controls were included in the current meta-analysis, which together comprised a total of 32 publications. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate relationships between the PLCE1 polymorphisms and cancer susceptibility. All statistical analyses were performed using Stata 11 software.

Results: Results of the meta-analysis demonstrated that the rs2274223 polymorphism showed a significant correlation with increased overall cancer susceptibility (AG vs. AA: OR 1.168, 95% CI 1.084–1.259; GG vs. AA: OR 1.351, 95% CI 1.163–1.570; AG+GG vs. AA: OR 1.193, 95% CI 1.103–1.290; GG vs. AA+AG: OR 1.262, 95% CI 1.102–1.446; G vs. A: OR 1.163, 95% CI 1.089–1.242). Results of subgroup analysis showed that the rs2274223 polymorphism was associated with higher risk for esophageal cancer and gastric cancer relative to colorectal cancer and head and neck cancer. In addition, the rs2274223 polymorphism was found to be associated with increased cancer risk, especially among the subgroups comprising Asians, studies with population-based controls, studies employing the TaqMan genotyping method, and studies consistent with Hardy-Weinberg equilibrium (HWE). The association between the rs3765524 polymorphism and reduced overall cancer risk was detected in one specific genetic model (CT vs. CC: OR 0.681, 95% CI 0.523–0.886). Results of subgroup analysis showed that the rs3765524 polymorphism was associated with cancer risk in a specific genetic model among the subgroups of colorectal cancer, esophageal cancer, Asians, studies with population-based controls, and studies consistent with HWE. However, relationships among the PLCE1 rs753724, rs11187842, and rs7922612 polymorphisms and tumor risk were not identified.

Conclusions: Results of the current meta-analysis suggested that PLCE1 (rs2274223, rs3765524) polymorphisms are associated with cancer susceptibility.

A Variant of COL3A1 (rs3134646) Is Associated With Risk of Developing Diverticulosis in White Men

BACKGROUND

Colonic diverticulosis is one of the most common gastroenterological disorders. Although diverticulosis is typically benign, many individuals develop diverticulitis or other aspects of diverticular disease. Diverticulosis is thought to stem from a complex interaction of environmental, dietary, and genetic factors; however, the contributing genetic factors remain unknown.

OBJECTIVE

The aim of our present study was to determine the role of genetic variants within genes encoding for collagens of the connective tissue in diverticulosis.

DESIGN

This was a transsectional genetic association study.

SETTINGS

This study was conducted at three tertiary referral centers in Germany and Lithuania.

PATIENTS

Single-nucleotide polymorphisms in COL3A1 (rs3134646, rs1800255) and COL1A1 (rs1800012) were genotyped in 422 patients with diverticulosis and 285 controls of white descent by using TaqMan assays.

MAIN OUTCOME MEASURES

The association of colonoscopy-proven diverticulosis with genetic polymorphisms with herniations was assessed in multivariate models.

RESULTS

The rs3134646, rs1800255, and rs1800012 variants were significantly associated with the risk of developing diverticulosis in the univariate model; however, these associations were not significant in the multivariate logistic regression analysis including additional nongenetic variables. When selectively analyzing sexes, the genotype AA (AA) in rs3134646 remained significantly associated with diverticulosis in men (OR, 1.82; 95% CI, 1.04-3.20; p = 0.04).

LIMITATIONS

Because a candidate approach was used, additional relevant variants could be missed. Within our cohort of patients with diverticulosis, only a small proportion had diverticular disease and thus, we could not examine the variants in these subgroups. Functional studies, including the analysis of the involved collagens, are also warranted.

CONCLUSIONS

Our study shows that a variant of COL3A1 (rs3134646) is associated with the risk of developing colonic diverticulosis in white men, whereas rs1800255 (COL3A1) and rs1800012 (COL1A1) were not associated with this condition after adjusting for confounding factors. Our data provide novel valuable insights in the genetic susceptibility to diverticulosis. See Video Abstract at http://links.lww.com/DCR/A504.

PLCE1 polymorphisms and expression combined with serum AFP level predicts survival of HBV-related hepatocellular carcinoma patients after hepatectomy

Polymorphisms in the phospholipase C epsilon (PLCE) 1 gene play a crucial role in the development and progression of several types of cancer. The present study investigated the prognostic significance of PLCE1 gene polymorphisms and expression combined with serum α-fetoprotein (AFP) level in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Single nucleotide polymorphisms were genotyped by sequencing DNA isolated from surgically resected tumor samples of 421 HBV-related HCC patients, and expression profiles were generated based on the GSE14520 dataset. A joint-effects analysis of PLCE1 haplotypes (Ars2274223Crs3765524; Grs2274223Trs3765524) with AFP level stratified at 20 ng/ml showed a significant association with overall survival(OS) of HBV-related HCC patients(log-rank P=0.0003). Patients with AC and GT haplotypes with AFP level ≥ 20 ng/ml had an increased risk of death as compared to those with the AC haplotype and AFP level < 20 ng/ml (adjusted P=0.029 and 0.041, respectively). Patients with the GT haplotype and AFP level < 20 ng/ml also had an increased risk of death, although with a non-significant P value (adjusted P=0.092). Joint-effects analysis of PLCE1 mRNA expression with serum AFP level stratified at 300 ng/ml was significantly associated with HBV-related HCC recurrence and OS. Our results demonstrate that PLCE1 haplotypes (including rs2274223 and rs3765524) and expression combined with serum AFP level may predict postoperative outcome of HBV-related HCC patients.

Genetic variants of mucins: unexplored conundrum

Alternative gene splicing, occurring ubiquitously in multicellular organisms can produce several protein isoforms with putatively different functions. The enormously extended genomic structure of mucin genes characterized by the presence of multiple exons encoding various domains may result in functionally diverse repertoire of mucin proteins due to alternative splicing. Splice variants (Svs) and mutations in mucin genes have been observed in various cancers and shown to participate in cancer progression and metastasis. Although several mucin Svs have been identified, their potential functions remain largely unexplored with the exception of the Svs of MUC1 and MUC4. A few studies have examined the expression of MUC1 and MUC4 Svs in cancer and indicated their potential involvement in promoting cancer cell proliferation, invasion, migration, angiogenesis and inflammation. Herein we review the current understanding of mucin Svs in cancer and inflammation and discuss the potential impact of splicing in generating a functionally diverse repertoire of mucin gene products. We also performed mutational analysis of mucin genes across five major cancer types in International Cancer Genome Consortium database and found unequal mutational rates across the panel of cancer-associated mucins. Although the functional role of mucins in the pathobiology of various malignancies and their utility as diagnostic and therapeutic targets remain undisputed, these attributes need to be reevaluated in light of the potentially unique functions of disease-specific genetic variants of mucins. Thus, the expressional and functional characterization of the genetic variants of mucins may provide avenues to fully exploit their potential as novel biomarkers and therapeutic targets.

Association between polymorphisms of TAS2R16 and susceptibility to colorectal cancer

BACKGROUND

Genetics plays an important role in the susceptibility to sporadic colorectal cancer (CRC). In the last 10 years genome-wide association studies (GWAS) have identified over 40 independent low penetrance polymorphic variants. However, these loci only explain around 1‑4% of CRC heritability, highlighting the dire need of identifying novel risk loci. In this study, we focused our attention on the genetic variability of the TAS2R16 gene, encoding for one of the bitter taste receptors that selectively binds to salicin, a natural antipyretic that resembles aspirin. Given the importance of inflammation in CRC, we tested whether polymorphic variants in this gene could affect the risk of developing this neoplasia hypothesizing a role of TAS2R16 in modulating chronic inflammation within the gut.

METHODS

We performed an association study using 6 tagging SNPs, (rs860170, rs978739, rs1357949, rs1525489, rs6466849, rs10268496) that cover all TAS2R16 genetic variability. The study was carried out on 1902 CRC cases and 1532 control individuals from four European countries.

RESULTS

We did not find any statistically significant association between risk of developing CRC and selected SNPs. However, after stratification by histology (colon vs. rectum) we found that rs1525489 was associated with increased risk of rectal cancer with a (P_trend of = 0.0071).

CONCLUSIONS

Our data suggest that polymorphisms within TAS2R16 gene do not have a strong influence on colon cancer susceptibility, but a possible role in rectal cancer should be further evaluated in larger cohorts.

Association between PSCA gene polymorphisms and the risk of cancer: an updated meta-analysis and trial sequential analysis

Previous studies have investigated the relationships between PSCA rs2294008 C>T and rs2976392 G>A polymorphisms and cancer susceptibility. However, the available findings remained inconsistent and even controversial. Thus, the aim of this meta-analysis was performed to clarify such associations. The online databases PubMed, EMBASE and Web of Science searched for relevant studies, covering all the papers published until September 1st, 2016. Data were pooled by odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the strength of such associations. Then, trial sequential analysis was performed to estimate whether the evidence of the results was firm. Overall, a significant increased risk of cancer was associated with PSCA rs2294008 C>T and rs2976392 G>A polymorphisms. For the PSCA rs2294008 polymorphism, when stratified by type of cancer, the results were significant especially in gastric cancer and bladder cancer. Moreover, in the subgroup analysis by ethnicity, significant results were detected in both Asian and Caucasian populations. Similarly, for the PSCA rs2976392 polymorphism, the stratification analyses by type of cancer showed that the results were significant only in gastric cancer. In addition, the stratification analyses by ethnicity detected that this polymorphism increased cancer risk only in Asian populations. Then, trial sequential analyses demonstrated that the results of the meta-analysis were based on sufficient evidence. Therefore, this meta-analysis suggested that the PSCA rs2294008 C>T and rs2976392 G>A polymorphisms might be associated with cancer susceptibility, which might act as a potential predicted biomarker for genetic susceptibility to cancer, especially in gastric cancer and bladd er cancer.

The controversial role of phospholipase C epsilon (PLCε) in cancer development and progression

The phospholipase C (PLC) enzymes are important regulators of membrane phospholipid metabolism. PLC proteins can be activated by the receptor tyrosine kinases (RTK) or G-protein coupled receptors (GPCR) in response to the different extracellular stimuli including hormones and growth factors. Activated PLC enzymes hydrolyze phosphoinositides to increase the intracellular level of Ca²⁺ and produce diacylglycerol, which are important mediators of the intracellular signaling transduction. PLC family includes 13 isozymes belonging to 6 subfamilies according to their domain structures and functions. Although importance of PLC enzymes for key cellular functions is well established, the PLC proteins belonging to the ε, ζ and η subfamilies were identified and characterized only during the last decade. As a largest known PLC protein, PLCε is involved in a variety of signaling pathways and controls different cellular properties. Nevertheless, its role in carcinogenesis remains elusive.

The aim of this review is to provide a comprehensive and up-to-date overview of the experimental and clinical data about the role of PLCε in the development and progression of the different types of human and experimental tumors.

Impact of DCC (rs714) and PSCA (rs2294008 and rs2976392) Gene Polymorphism in Modulating Cancer Risk in Asian Population

Multiple studies have investigated the association of gene variant of Deleted in colorectal carcinoma (DCC) and Prostate Stem cell antigen (PSCA) with various cancer susceptibility; however, the results are discrepant. Since SNPs are emerging as promising biomarker of cancer susceptibility, here, we aimed to execute a meta-analysis of DCC (rs714 A > G) and PSCA (rs2294008 C > T, rs2976392 G > A) polymorphism to demonstrate the more accurate strength of these associations. We followed a rigorous inclusion/exclusion criteria and calculated the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Overall, the pooled analysis showed that the DCC rs714 conferred increased risk of cancer only in Asians (AA vs. GG: OR = 1.86, p ≤ 0.0001; AG vs. GG: OR = 1.43, p = 0.005; GA + AA vs. GG: OR = 1.66, p ≤ 0.0001; AA vs. GG + GA; OR = 1.52, p ≤ 0.004, A vs. G allele: OR = 1.41, p ≤ 0.0001). PSCA rs2294008 was associated with increased overall cancer risk (TT vs. CC: OR = 1.28, p = 0.002; CT vs. CC: OR = 1.21, p ≤ 0.0001; CT + TT vs. CC: OR = 1.24, p ≤ 0.0001; TT vs. CC + CT; OR = 1.17, p ≤ 0.005, T vs. C allele: OR = 1.16, p ≤ 0.0001); however, in stratified analysis this association was limited only to gastric and bladder cancer and the strength was more prominent in Asians. In contrast, the PSCA rs2976392 SNP did not modulate the cancer risk. Therefore, we concluded that rs714 and rs2294008 polymorphism may represent a potential genetic biomarker for cancer risk in Asians and gastric as well as bladder cancer, respectively. However, since our study is limited to Asians and cancer types, further larger studies involving other cancers and/or population, gene-environment interactions and the mechanism of DCC and PSCA gene deregulation are desired to define the role of genotype with overall cancer risk.

A Multiple Interaction Analysis Reveals ADRB3 as a Potential Candidate for Gallbladder Cancer Predisposition via a Complex Interaction with Other Candidate Gene Variations

Gallbladder cancer is the most common and a highly aggressive biliary tract malignancy with a dismal outcome. The pathogenesis of the disease is multifactorial, comprising the combined effect of multiple genetic variations of mild consequence along with numerous dietary and environmental risk factors. Previously, we demonstrated the association of several candidate gene variations with GBC risk. In this study, we aimed to identify the combination of gene variants and their possible interactions contributing towards genetic susceptibility of GBC. Here, we performed Multifactor-Dimensionality Reduction (MDR) and Classification and Regression Tree Analysis (CRT) to investigate the gene–gene interactions and the combined effect of 14 SNPs in nine genes (DR4 (rs20576, rs6557634); FAS (rs2234767); FASL (rs763110); DCC (rs2229080, rs4078288, rs7504990, rs714); PSCA (rs2294008, rs2978974); ADRA2A (rs1801253); ADRB1 (rs1800544); ADRB3 (rs4994); CYP17 (rs2486758)) involved in various signaling pathways. Genotyping was accomplished by PCR-RFLP or Taqman allelic discrimination assays. SPSS software version 16.0 and MDR software version 2.0 were used for all the statistical analysis. Single locus investigation demonstrated significant association of DR4 (rs20576, rs6557634), DCC (rs714, rs2229080, rs4078288) and ADRB3 (rs4994) polymorphisms with GBC risk. MDR analysis revealed ADRB3 (rs4994) to be crucial candidate in GBC susceptibility that may act either alone (p < 0.0001, CVC = 10/10) or in combination with DCC (rs714 and rs2229080, p < 0.0001, CVC = 9/10). Our CRT results are in agreement with the above findings. Further, in-silico results of studied SNPs advocated their role in splicing, transcriptional and/or protein coding regulation. Overall, our result suggested complex interactions amongst the studied SNPs and ADRB3 rs4994 as candidate influencing GBC susceptibility.