Putatively Functional PLCE1 Variants and Susceptibility to Esophageal Squamous Cell Carcinoma (ESCC): A Case-Control Study in Eastern Chinese Populations
ABSTRACT A novel variant rs2274223 located in the phospholipase C epsilon 1 (PLCE1) gene was found to be associated with risk of esophageal squamous cell carcinoma (ESCC) by 2 large-scale genome-wide association studies (GWASs) in Chinese populations. In this study, we aimed to assess such an association in an eastern Chinese population and to address its possibly functional role in the etiology of ESCC.
A total of 1061 ESCC cases and 1211 controls were recruited and successfully genotyped for 2 single nucleotide polymorphisms (SNPs) (rs2274223 and rs11187870) of the PLCE1 gene by the TaqMan assay. Real-time PCR and immunohistochemical (IHC) analysis were applied to assess mRNA and protein expression levels, respectively, in a subset of tumor samples.
SNP rs2274223 was independently associated with risk of ESCC (adjusted odds ratio [OR], 1.49; 95% confidence interval [95% CI], 1.03-2.17 for GG vs AA), and SNP rs11187870 was also found to be associated with risk of ESCC assuming a dominant model (adjusted OR, 1.20; 95% CI, 1.00-1.44 for CG/CC vs GG). The Grs2274223Crs11187870 haplotype increased the risk for ESCC by 1.22-fold (95% CI, 1.04-1.42). Further experiments showed that overall PLCE1 mRNA expression was lower in tumor than in paired normal tissues (0.067±0.016 vs 0.264±0.067, P<.05), and the IHC analysis showed the normal tissues of rs2274223 GG genotype had a lower PLCE1 staining score than that of the AG genotype (0.40±0.22 vs 1.33±0.32, P<.05).
PLCE1 SNP rs2274223 A>G change may reduce gene expression, and the variant G genotypes might contribute to risk of ESCC.
[Show abstract] [Hide abstract]
ABSTRACT: Recent genome-wide association studies (GWAS) have identified variants in phospholipase C epsilon1 (PLCE1) as novel susceptibility markers for esophageal squamous cell carcinoma (ESCC) in Chinese population. Although few studies have replicated this findings in other populations, but results are contradictory. So, we aimed to replicate association of two previously reported non-synonymous polymorphisms (rs2274223A>G and rs3765524C>T) from haplotype block 10 and evaluated a novel variant (rs7922612C>T) from haplotype block 2 of PLCE1 with susceptibility and prognosis of ESCC in northern Indian population. The genotyping of PLCE1 variants were performed in 293 histopathologically confirmed incident ESCC cases (including 177 follow-up cases) and 314 age-, gender-, and ethnicity-matched controls using PCR RFLP. All statistical analyses were performed through SPSS version 15.0. Modeling and functional prediction of two non-synonymous variants were carried out using bioinformatics tools. PLCE1 polymorphisms were not associated with susceptibility to ESCC or its clinical phenotypes (tumor location/lymph node metastasis). No interaction with environmental risk factors was found. In silico analysis suggested negligible effect on structure of PLCE1 protein due to PLCE1 rs2274223 (H1927R) and rs3765524 (T1777I) polymorphisms. Survival analysis showed PLCE1 rs7922612CT + TT genotype conferred adverse outcome to ESCC patients. Our study for the first time suggests that GWAS originated PLCE1 variants do not have independent role in susceptibility of ESCC in northern Indian population; however, a novel haplo-tagging SNP rs7922612 may modify survival outcome of ESCC patients.Tumor Biology 11/2014; DOI:10.1007/s13277-014-2458-z · 2.84 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Several genetic variants including PSCA rs2294008 C>T and rs2976392 G>A, MUC1 rs4072037 T>C, and PLCE1 rs2274223 A>G have shown significant association with stomach cancer risk in the previous genome-wide association studies (GWASs). To evaluate associations of these SNPs in the Han Chinese, an independent hospital based case-control study was performed by genotyping these four polymorphisms in a total of 692 stomach cancer cases and 774 healthy controls acquired by using frequency matching for age and gender. False-positive report probability (FPRP) analysis was also performed to validate all statistically significant findings. In the current study, significant association with stomach cancer susceptibility was observed for all the four polymorphisms of interest. Specifically, a significant increased stomach cancer risk was associated with PSCA rs2294008 (CT vs. CC: adjusted OR = 1.37, 95% CI = 1.07-1.74, and CT/TT vs.CC: adjusted OR = 1.30, 95% CI = 1.03-1.63), PSCA rs2976392 (AG vs. GG: adjusted OR = 1.30, 95% CI = 1.02-1.65, and AG/AA vs. GG: adjusted OR = 1.26, 95% CI = 1.00-1.59), or PLCE1 rs2274223 (AG vs. AA: adjusted OR = 1.48, 95% CI = 1.15-1.90, and AG/GG vs. AA: adjusted OR = 1.45, 95% CI = 1.14-1.84), respectively. In contrast, MUC1 rs4072037 was shown to decrease the cancer risk (CT vs. TT: adjusted OR = 0.77, 95% CI = 0.60-0.98). Patients with more than one risk genotypes had significant increased risk to develop stomach cancer (adjusted OR = 1.30, 95% CI = 1.03-1.64), when compared with those having 0-1 risk genotypes. Stratified analysis indicated that the increased risk was more pronounced in younger subjects, men, ever smokers, smokers with pack years ≤ 27, patients with high BMI, or non-cardia stomach cancer. This study substantiated the associations between four previous reported genetic variants and stomach cancer susceptibility in an independent Han Chinese population. Further studies with larger sample size and different ethnicities are warranted to validate our findings.PLoS ONE 02/2015; 10(2):e0117576. DOI:10.1371/journal.pone.0117576 · 3.53 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Phospholipase C epsilon 1 (PLCE1) plays an important role in cell growth, differentiation and oncogenesis. An increasing number of individual studies have investigated the association between PLCE1 rs2274223 polymorphism and cancer risk, but the conclusions are inconclusive. To obtain a comprehensive conclusion, we performed a meta-analysis of 22 studies with 13188 cases and 14666 controls. The pooled results indicated that PLCE1 rs2274223 A>G polymorphism was associated with an increased risk of overall cancer (G vs. A: OR=1.15, 95% CI=1.06-1.25; GG vs. AA: OR=1.30, 95% CI=1.10-1.55; GA vs. AA: OR=1.18, 95% CI=1.08-1.30; GG/GA vs. AA: OR=1.20, 95% CI=1.08-1.32; GG vs. GA/AA: OR=1.22, 95% CI=1.04-1.42). The stratification analysis showed the polymorphism was significantly associated with an increased risk of esophageal squamous cell carcinoma (ESCC) other than gastric cancer (GC), especially among the subgroups of Asian, high quality score , sample size >1000 and the studies consistent with Hardy-Weinberg equilibrium (HWE). This meta-analysis demonstrated that PLCE1 rs2274223 A>G polymorphism may be associated with increased susceptibility to cancer, especially for ESCC. However, due to the substantial heterogeneities across the studies, the conclusion might be not conclusive that need more studies to confirm.Scientific Reports 01/2015; 5. DOI:10.1038/srep07986 · 5.08 Impact Factor