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-DR 4, 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 prevalenc e of skin cancer. Design: HLA typing was performed in 124 white individuals with histological ly 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 carc inoma 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 po tentially confounding factor for the association between HLA alleles and sk in cancer, did not substantially alter this association. No other associati ons 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 betwee n HLA-DR7 and basal cell carcinoma.