Potencial de uso de polimorfismos genéticos, proteínas reguladoras do ciclo celular e miRNAs como biomarcadores de suscetibilidade, diagnóstico e/ou prognóstico de neoplasias cervicais

• Autor(a) principal: Torres, Sandra Liliana Vargas
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12688
• topic: Cervical neoplasia; Genetic polymorphisms; Regulatory proteins of the cell cycle; Immunohistochemistry; miRNAs; RT-qPCR; Neoplasia cervical; Polimorfismos genéticos; Proteínas reguladoras do ciclo celular; Imuno-histoquímica; miRNAs; RT-qPCR; Colo uterino Câncer; Polimorfismo (Genética); Proteínas; Neoplasias do colo do útero; Imuno-histoquímica; MicroRNAs; Reação em cadeia de polimerase em tempo real; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA HUMANA E MEDICA

Cervical cancer is the third most common malignancy among women in Brazil. Several environmental, behavioral, biological and genetic factors work in association with the persistent infection with human papillomavirus (HPV), which is recognized as the etiologic agent for this type of cancer. One of our objectives was to investigate the importance of the polymorphisms MDM2 285G>C, MDM2 309T>G and p21 70C>T, analysed in the present work, and p53 PIN3A1>A2, p53 72C>G, p21 31C>A CDKN2a 500C>G e CDKN2a 540C>T, which were analyzed in previous studies, for the development and/or severity of cervical neoplasias. Expression of the proteins MDM2, MDM4, E2F2, CCNE2 and p14 and the mi-RNAs miR-34a and miR-24 were also analyzed, individually or in combination with the expression of the proteins p53, p21 and p16, and HPV status, previously investigated. We selected 498 women living in Rio de Janeiro, with 299 being diagnosed with histopathological low grade cervical neoplasia (LSIL), high grade (HSIL) and cancer group of cases, and 199 without current or previous history of cervical cytologic changes group of controls. Genetic polymorphisms were analyzed by PCR-RFLP (polymerase chain reaction - restriction fragment length polymorphism) and/or Sanger sequencing techniques. Protein expression was assessed by immunohistochemistry (Tissue Microarray - TMA), and the expression of miRNAs was analyzed by RT-qPCR (Real-Time Quantitative Reverse Transcription PCR) in 99 and 53 biopsies of the group of cases, respectively. Genotype and allele distributions corresponding to MDM2 309T>G showed no significant differences between the study groups. The allele MDM2 285C was only observed among cases. Comparison between cases and controls revealed a protective effect attributed to the p21 70TT genotype (OR = 0.33, 95% CI = 0.12-0.89). Differently than individual analysis of polymorphisms, some gene-gene interactions exhibited significant ORs for the development or severity of cervical neoplasia. Gene-environment interactions revealed some gentoypes as risk modifiers of certain variables, as the genotype MDM2 309GG, which increased the risk associated with the family history of cancer. Patients carrying the genotypes MDM2 309TG or GG and carriers of the genotypes CDKN2a 540CT or TT had, respectively, higher and lower chance of being diagnosed with HSIL or cancer under 30 years of age. The expression pattern of the proteins MDM4, CCNE2, p16, p21 and p53 showed a positive, although weak or moderate, correlation with the severity of cervical lesion, and an inverse correlation with the HPV-16 status. No significant difference was observed between the relative expression of mi-R24 and miR34a and the cervical lesion groups or between miRNAs and protein expression. Further studies in larger populations are needed to corroborate some of our findings and validate their potential use in clinical practice.