Higher Levels of BRCA1 Gene Methylation in Sporadic Breast Cancer Patients with a Lower Incidence of Recurrence

Background: Breast cancer is the most prevalent malignant disease among women. Here, we investigate whether there is an association between disease recurrence in breast cancer patients and the quantitative methylation pattern of seven genes of different DNA repair pathways. Methods: Clinical and pathological data from 30 patients treated for sporadic breast cancer were selected according to the following inclusion criteria: follow-up of 5 years, adjuvant chemotherapy and recurrence. Histopathology was verified, and genomic DNA was accessed by tumor cryosectioning. We also determined the methylation levels of seven DNA repair genes (BRCA1, BRCA2, XRCC1, PARP1, ERCC4, MGMT, and XPC). Results: Patients without recurrence demonstrated a higher index of positive progesterone receptor status compared to patients with recurrence (p = 0.025). All other clinical characteristics of the patients did not differ between the groups. BRCA1 and BRCA2 genes showed methylation, and there was a higher level of BRCA1 gene methylation in patients without recurrence. BRCA1 methylation was not associated with the clinical characteristics of patients. All other genes analyzed showed no difference in methylation between patients with and without recurrence. Conclusions: We showed that sporadic breast cancer patients with a lower incidence of recurrence demonstrate a higher level of BRCA1 gene methylation after 5 years of follow-up, suggesting its role as a predictive biomarker.