RESUMO
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.
Assuntos
Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único/genética , Proteína do Retinoblastoma/genética , Retinoblastoma/genética , Proteína Supressora de Tumor p53/genética , Criança , Pré-Escolar , DNA de Neoplasias/genética , Frequência do Gene/genética , Humanos , MéxicoRESUMO
BACKGROUND: This study was undertaken in order to analyze the genetic incidence of human lymphocyte antigen diabetic retinopathy (HLA-DR) and its influence in proliferative diabetic retinopathy (PDR). METHODS: We designed a case-control study in which 127 mestizo Mexican patients with DM II and diabetic retinopathy were studied. DNA was extracted and HLA-DR regions were amplified using PCR. Alleles were determined by DNA hybridization. Diagnosis was assessed clinically and by fluorescein angiography. Incidence of HLA-DR alleles in patients was compared with an ethnically matched control group of healthy subjects (n = 98). Statistical significance was established with non-parametric tests. RESULTS: Patients with diabetic retinopathy showed less frequency of HLA-D11 compared with the control group (p = 0.043). NPDR patients with 10 or more years of DM II showed an increase of HLA-DR7 (p = 0.01). CONCLUSIONS: Our results suggest that the presence of HLA-DR7 protects against the development of proliferative disease in the diabetic Mexican population.