Study of human leukocyte antigen class I phenotypes in Moroccan patients with nasopharyngeal carcinoma.

Previous reports demonstrated an association between the human leukocyte antigen (HLA) and risk for nasopharyngeal carcinoma (NPC) among the Chinese in Singapore, a population with a high incidence of this malignancy. In our study, we assess the association between HLA and NPC in Morocco, a median-prevalence area for this cancer, where NPC presents the particularity of also affecting young individuals. Using the standard microlympho-cytotoxicity test, we typed a total of 154 Moroccan NPC patients and 257 unrelated healthy controls for their HLA-A and B antigens. The results of these analyses show that the frequencies of HLA-A10, HLA-B13 and HLA-B18 were found to be higher in the NPC group than in the control group, whereas HLA-A9 was associated with a decreased risk. After correction for the number of specificities tested, these differences were statistically significant only for HLA-B18 (corrected p value [pc] < 0.023, relative risk [RR] = 4.14) and HLA-A9 (pc < 0.023, RR = 0.45). The comparison of the distribution of the HLA antigens in younger and older cohorts of patients shows that the incidence of HLA-A10 and HLA- B18 was higher in the older group, whereas the frequencies of HLA-A19 and HLA-B13 were significantly higher in younger patients compared with controls. The presence of both HLA-A19 and HLA-B13 phenotypes correlated with an increased risk of developing NPC among overall patients compared with controls. According to the sex distribution, increased frequency of HLA-B18 was found in male and female NPC patients compared with controls, whereas the frequency of HLA-A10 was higher only in male NPC patients compared with controls.