Novel genetic locus at MHC region for esophageal squamous cell carcinoma in Chinese populations.

BACKGROUND:Our previous genome-wide association study (GWAS) identified three independent single nucleotide polymorphisms (SNPs) in human major histocompatibility complex (MHC) region showing association with esophageal squamous cell carcinoma (ESCC). In this study, we increased GWAS sample size on MHC region and performed validation in an independent ESCC cases and normal controls with aim to find additional loci at MHC region showing association with an increased risk to ESCC. METHODS:The 1,077 ESCC cases and 1,733 controls were genotyped using Illumina Human 610-Quad Bead Chip, and 451 cases and 374 controls were genotyped using Illumina Human 660W-Quad Bead Chip. After quality control, the selected SNPs were replicated by TaqMan genotyping assay on another 2,026 ESCC cases and 2,384 normal controls. RESULTS:By excluding low quality SNPs in primary GWAS screening, we selected 2,533 SNPs in MHC region for association analysis, and identified 5 SNPs with p