Correlation between BRCA1 expression and the advanced stage of triple‑negative breast cancer

Triple-negative breast cancer (TNBC) is highly aggressive and has a poor prognosis. TNBC is commonly reported in young women and often relapses quickly, exhibiting aggressive characteristics. It is also linked to a loss of function of BRCA1. Patients with BRCA mutations require different treatments because this tumor type is sensitive to platinum-based chemotherapy regimens and inhibitors of the poly (ADP ribose) polymerase. The present study aimed to investigate the prognostic significance of BRCA1 expression in Indonesian patients with TNBC. The study included 57 patients with TNBC. Epidermal growth factor receptor and cytokeratin 5/6 immunostaining were used to classify TNBC into basal-like and non-basal-like subtypes. The BRCA1 expression was also determined using immunohistochemistry. Pearson's Chi-square analysis and Fisher's exact test were used to examine correlations between variables. Kaplan-Meier method was used to analyze the survival rate. Patients with TNBC had an average age of 55.18±10.014; most of them were ≥50 years-old, had high-grade tumors (75.4%), and were in the advanced stages of cancer (82.5%). The majority had no specific type of cancer (78.9%), received non-platinum-based therapies (64.9%), had basal-like subtypes (72.9%), and were still alive (56.1%). Negative BRCA1 expression was higher (52.6%) than positive expression (47.4%) and correlated with advanced cancer stage (P=0.035). However, the BRCA1 expression was not correlated with other clinicopathological variables and the types of therapy. Survival analysis showed that the stage and BRCA1 expression acted as insignificant prognostic factors in patients with TNBC (P=0.091 and P=0.150). In the present study, negative BRCA1 expression was correlated with advanced stage but did not act as a prognostic factor in Indonesian patients with TNBC.