Abstract
An association between specific human leukocyte antigens (HLA) alleles and nasopharyngeal carcinoma (NPC) has been reported for sporadic NPC, but studies of familial NPC are lacking. We evaluated this association with familial NPC in a study of 301 NPC cases and 1010 family and community controls from Taiwan. Class I HLA alleles were characterized using a sequence-based typing protocol. Allele frequencies between case and control groups were compared by chi(2) or exact tests. For alleles associated with NPC, odds ratios (OR) and 95% confidence intervals (CI) were calculated. Similar allelic frequency distribution and HLA associations were found as those previously reported for sporadic NPC: protective effect for HLA-A*1101 and increased risk for HLA-A*0207, HLA-A*3303, HLA-B*3802, and HLA-B*5801. Overall, the magnitude of observed associations was weakest when cases were compared with sibling controls and strongest when compared with unrelated community controls. Evaluating the joint effect of HLA-A*0207 and HLA-B*4601, individuals who were carriers of HLA-A*0207 with or without the presence of HLA-B*4601 had a 1.9-fold (95% CI = 1.0-3.4) and 2.1-fold (95% CI = 0.83-5.3) risk of NPC, respectively. Conversely, carriers of HLA-B*4601 in the absence of HLA-A*0207 had a 50% reduction in NPC risk (95% CI = 0.27-0.93). Comparable findings from our family study and those from previous sporadic studies were found with the notable exception of a lack of positive association between HLA-B*4601 and familial NPC in the absence of HLA-A*0207. This finding requires replication in larger studies.