Association of HLA-G polymorphisms with nasopharyngeal carcinoma risk and clinical outcome

The expression of human leukocyte antigen-G (HLA-G) in tumor cells may facilitate the escape of the tumor from immunosurveillance; thus the aim of this study was to evaluate the influence of HLA-G polymorphisms occurrence on nasopharyngeal carcinoma (NPC) susceptibility, severity, and survival. Using the restriction fragment length polymorphism-polymerase chain reaction and the amplification refractory mutation system-polymerase chain reaction method, 186 Tunisian patients and 189 healthy controls were genotyped for nonsynonymous polymorphisms in HLA-G codon 31Thr/Ser, codon 110Leu/Ile and codon 130Leu/framshift. When allele, genotype and haplotype frequencies between patients and controls were compared for each single nucleotide polymorphisms (SNP), no statistical significant differences were observed. According to the lymph node status and the tumor stages, the Ile110 allele was shown to be significantly less frequent among patients with a positive lymph node status and more severe tumor stages (stage I-II vs III-IV), respectively. Moreover, the codon 130C deletion occurrence was significantly associated with a decreased NPC free disease and overall survival. Altogether our results suggest a possible role for HLA-G locus in NPC progression and aggressiveness.