Study of polymorphisms in the TP53 and RB1 genes in children with retinoblastoma in northern Mexico

PURPOSE To determine the frequency and association of polymorphisms in the TP53 and RB1 genes with clinical characteristics in a group of children with retinoblastoma (RB) in northern Mexico. METHODS A prospective, longitudinal, and analytical study of 11 patients diagnosed with RB was conducted. Endpoint PCR and high-resolution real-time PCR were performed. Chi-square and Student t tests were used to evaluate associations between variables. Allelic frequencies, as well as genotypic and Hardy-Weinberg equilibriums, were evaluated using Guo and Thompson's method. RESULTS We found a statistically significant difference between the polymorphism RB1-GG/rs9568036 and tumor chemoresistance (p<0.05). The allelic variants RB1-AA and AG/rs9568036 were determined to be associated with tumor chemosensitivity (p<0.05). A statistically significant relation between the polymorphism RB1-GG/rs9568036 and males (p = 0.0386), rate ratio (RR) = 2.0 (95% confidence interval [CI] = 0.76-5.32), as well as between the allelic variants RB1-AA and AG/rs9568036 and females (p = 0.0027), RR = 8.0 (95% CI = 1.28-50.04), was observed. We also observed a statistically significant association between the rs1042522 polymorphism in the TP53 gene and unilateral presentation of the disease. CONCLUSIONS The rs9568036 polymorphism in the RB1 gene and the allelic variants can be associated with type of response to medical therapy and associated with male sex, while the allelic variant rs1042522 polymorphism in the TP53 gene is associated with the unilateral presentation of the disease in a group of Mexican children with RB.