Relação dos polimorfismos dos genes TP53 e ATM em pacientes com câncer de mama e efeitos colaterais à radioterapia.

Abstract

The purpose of this study wasto evaluate the association of single nucleotide polymorphisms of ATM and TP53 genes in breast cancer patients with skin and subcutaneous systems morbidity after radiotherapy. These two genes encode important proteins of the DNA repair pathways. It is believed that their polymorphisms are likely to modify the response of normal tissues to radiation. A group of 78 patients of the Radiotherapy Service at Araújo Jorge Hospital (Associação de Combate ao Câncer em Goiás) was selected. After signing the informed consent agreement, a sample of peripheral blood was collected for subsequent DNA extraction and polymerase chain reaction (PCR) for amplification of ATM and TP53 gene fragments. Finally the amplified fragments were sequenced to verify the presence of an exchange G> A in the codon 1853 of the ATM gene and polymorphisms of TP53 gene (C> G in the codon 72). The side effects were classified according to the Radiation Therapy Oncology Group (RTOG) score. On univariate analysis,the expected effects of treatment with RT events showed that there was a significant association between aboost RT and its suspension with the acute effects of high-grade skin (OR = 3.05, 95% CI 1.175 to 7.928, p = 0.035) (OR = 3.808, 95% CI 1.213 to 11.958, p = 0.033), respectively. Side effects of acute high-grade skin were associated with a longer duration of treatment. (p=0.01 IC95% -11.546 - (-1,638). The type of surgery was significantly associated with late subcutaneous tissue (OR = 1.326, 95% CI 1.143 to 1.537, p = 0.016) side effects There was no association between polymorphisms TP53 and ATM analysed with acute and late side effects of skin nor subcutaneous tissue (RTOG ≥ 2) (p> 0.05).