Association of CTLA-4 (AT)n Variants in Basal Cell Carcinoma and Squamous Cell Carcinoma Patients from Western Mexico.

The incidence of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) is constantly increasing, becoming a significant health problem. CTLA-4 is a critical immune checkpoint, and it has been suggested that a variant of variable-number tandem repeat in the 3'-UTR of its gene, known as (AT)n, may be associated with a higher susceptibility to some cancers; however, little is known about genetic variants of the CTLA-4 gene in NMSC. To establish the association of this genetic variant in the CTLA-4 gene with the susceptibility of NMSC carcinogenesis in the Western Mexican population, samples from 150 BCC patients, 150 SCC patients, and 150 healthy individuals as the reference group (RG) were analyzed by endpoint PCR, followed by electrophoresis to genotype the samples. We found that the short-repeat 104/104 bp genotype may be a risk factor for BBC carcinogens (OR = 2.92, p = 0.03), whereas the long-repeat 106/106 bp genotype may be a protective factor for both BCC (OR = 0.13, p = 0.01) and SCC (OR = 0.32, p = 0.01) susceptibility. Our results show that in the Western Mexican population, long-repeat (AT)n variants in the CTLA-4 gene are associated with a protective factor in BCC and SCC. In contrast, short repeats are associated with a risk factor.