Further evidence for the existence of major susceptibility of nasopharyngeal carcinoma in the region near HLA-A locus in Southern Chinese

Background: Nasopharyngeal carcinoma (NPC) is a multi-factorial malignancy closely associated with environmental factors, genetic factors and Epstein-Barr virus infection. Human leukocyte antigen (HLA) complex, specially the region near HLA-A locus, was regarded as a major candidate region bearing NPC genetic susceptibility loci in many previous studies including two recent genome-wide association (GWA) studies. To provide further evidence for the NPC susceptibility in the region near HLA-A locus based on other previous studies, we carried out a two-stage hospital-based case control association study including 535 sporadic NPC patients and 525 cancer-free control subjects from Guangdong, a high prevalence area of NPC in China. Methods: 38 tag SNPs were initially selected by Heploview from the segment around HLA-A locus (from D6S211 to D6S510) and genotyped on GenomeLab SNPstream platform in 206 cases and 180 controls in the stage 1. Subsequently, the stage 1 significant SNPs and 17 additional SNPs were examined on another platform (Sequenom iPlex Assay) in another independent set of study population including 329 cases and 345 controls. Results: Totally eight SNPs from the segment from D6S211 to D6S510 within HLA complex were found to be significantly associated with NPC. Two of the most significant SNPs (rs9260734 and rs2517716) located near to HLA-A and HCG9 respectively were in strong LD with some other SNPs of this region reported by two previous GWA studies. Meanwhile, Meanwhile, novel independent susceptibility loci (rs9404952, Pcombined = 6.6 x 10(-5), OR combined = 1.45) was found to be close to HLA-G. Conclusion: Therefore, our present study supports that the segment from D6S211 to D6S510 in HLA complex region might contain NPC susceptibility loci which indeed needs to be fully investigated in the future.