Further evidence for an association of HLA-DR7 with basal cell carcinoma on the tropical island of Saba.

OBJECTIVE To establish the association of HLA alleles (ie, HLA-DR1, HLA-DR4, and HLA-DR7) with individuals with skin cancer on the tropical island of Saba. This island was chosen because most of the white population has fair skin and excessive exposure to sunlight, which results in a high prevalence of skin cancer. DESIGN HLA typing was performed in 124 white individuals with histologically proven basal cell and/or squamous cell carcinoma and in control subjects. Skin type, the presence of freckling, and the number of actinic keratoses were determined. SETTING Population-based study. SUBJECTS Inhabitants of Saba with and without skin cancer. MAIN OUTCOME MEASURE Presence of HLA-DR1, HLA-DR4, and HLA-DR7 alleles. RESULTS Associations of HLA alleles with basal cell and squamous cell carcinoma have been reported. The presence of the HLA-DR7 allele was positively associated with the development of basal cell carcinoma (odds ratio, 3.8; 95% confidence interval, 1.1-13.4). Adjustment for skin type, which is a potentially confounding factor for the association between HLA alleles and skin cancer, did not substantially alter this association. No other associations between HLA alleles and skin cancer were found, possibly because of the small size of the study population. CONCLUSION This study presented further evidence for an association between HLA-DR7 and basal cell carcinoma. Arch Dermatol. 2000;136:1019-1022