Lack of association between breast cancer and HLA (A and B) specificities: importance of age-matched controls.

HLA (A and B) antigen frequencies in 100 women with breast cancer were compared with those in 2 groups of cancer-free control women: the first control group (263 subjects) were age-unmatched, and the second (75 subjects) age-matched. The mean age and standard deviation were 56 +/- 13 years for the patient group, 25 +/- 3 years for the first control group, and 53 +/- 10 years for the second. It was first noted that HLA-B13 was significantly less prevalent among the patients with breast cancer when compared to the first control group (1% versus 7.2%, p = 0.025). However, when the patient group was compared to the second control group, no difference was found in the frequency of HLA-B13 (1% versus 1.3%, p = 0.80) or any other antigens. Age can be an important variable in a study of correlation between HLA and disease.