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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Adult, Aged, Antineoplastic Combined Chemotherapy Protocols, Breast Neoplasms, Chemotherapy, Adjuvant, Cyclophosphamide, Cytosine, Female, Fluorouracil, Gene Expression Regulation, Neoplastic, Genetic Predisposition to Disease, Genotype, Guanine, Humans, Mastectomy, Segmental, Methotrexate, Middle Aged, Neoplasm Recurrence, Local, Polymerase Chain Reaction, Polymorphism, Restriction Fragment Length, Polymorphism, Single Nucleotide, Predictive Value of Tests, Prognosis, Rad51 Recombinase, Radiotherapy, Adjuvant, Sequence Analysis, DNA, Treatment Outcome.
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Is the RAD51 135G > C polymorphism related to the effect of adjuvant therapy in early breast cancer? Context: RAD51, a central player in the response to DNA damage, has been suspected to contribute to tumour resistance to therapy. A single-nucleotide polymorphism, RAD51 135G>C, in the untranslated region of the RAD51 gene elevates breast cancer risk among BRCA2 carriers. In this study, it was investigated whether this polymorphism is related to prognosis of breast cancer and RAD51 protein expression and whether it is indicative of resistance to radiotherapy or cyclophosphamide/methotrexate/5-fluorouracil (CMF) chemotherapy. We genotyped 306 patients with early breast cancer, who were randomised to receive post-operative radiotherapy or CMF chemotherapy, for the RAD51 135G>C polymorphism. RAD51 protein expression was evaluated with immunohistochemistry. 15.4 % of the patients had at least one C-allele (three were C homozygotes). There was no correlation between genotype and protein expression. Patients who were G homozygotes benefitted from radiotherapy with decreased risk of local recurrences (RR = 0.32, 95 % C.I. 0.16-0.64, p = 0.001). CMF chemotherapy reduced the risk of distant recurrence for patients carrying at least one C-allele (RR = 0.29, 95 % C.I. 0.10-0.88, p = 0.03), whereas G homozygotes had no benefit from chemotherapy. There was a significant interaction between chemotherapy and genotype (p = 0.02).
assistant
The results suggest that the RAD51 135G>C polymorphism predicts CMF chemotherapy effect in early breast cancer. Final Decision: yes