Nasopharyngeal carcinoma V: immunogenetic studies of Southeast Asian ethnic groups with high and low risk for the tumor.

One hundred forty-four Chinese patients with nasopharyngeal carcinoma (NPC), 148 normal Chinese, and 88 patients, suspected on clinical grounds of having NPC but in whom no evidence of cancer was seen in histological preparations of biopsy tissue and who were therefore presumed to be free of NPC, have been studied for HL-A antigen patterns. The antisera used identified up to 8 1st-locus and up to 14 2nd-locus specificities. The two major findings in the NPC patients were a significantly increased frequency of HL-A2 and a nonspecific deficit of 2nd-locus antigens. The proportion of patients with the high-risk characteristic ( HL-A2 ; < 2 2nd-locus antigens) versus low-risk individuals (lacking HL-A2; 2 2nd-locus antigens) differed between the NPC patients and the comparison groups to a high order of statistical significance ( X 2 = 16.5; p = 0.00006; relative risk = 4.5).