Putatively Functional PLCE1 Variants and Susceptibility to Esophageal Squamous Cell Carcinoma (ESCC): A Case-Control Study in Eastern Chinese Populations

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 G(rs2274223)C(rs11187870) 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 +/- A 0.016 vs 0.264 +/- A 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 +/- A 0.22 vs 1.33 +/- A 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.