PROGNOSTIC VALUE OF BRCA1 IN BREAST CANCER PATIENTS TREATED WITH NEOADJUVANT ANTRHACYCLINE-BASED CHEMOTHERAPY

SOTTILE, MAYRA L; GOMEZ, LAURA C; REDONDO, ANALIA L; DAGUERRE, PABLO; LEUZZI, MARCELA; GAGO, FRANCISCO E; IBARRA, JORGE; VARGAS-ROIG, LAURA M

San Luis

Congreso; XXXVII Reunión Científica Anual Sociedad de Biología de Cuyo; 2019

Breast cancer is the leading cause of cancer death inwomen in Argentina. Anthracycline-based regimens represent the major chemotherapeuticagents used in breast cancer treatment. As DNA-damaging agents, anthracyclinesinduce DNA single and double strands breaks which are repaired by homologousrecombination (HR) mechanism. The expression of DNA repair proteins variesamong breast tumors and the DNA repair status can affect the chemotherapyresponse. The aim of our work was to determine the predictive/prognostic valueof HR proteins CtIP and BRCA1 in breast cancer patients treated withneoadjuvant doxorubicin (DOX) or epirubicin (EPI) monochemotherapy. BRCA1 andCtIP expression was evaluated by immunohistochemistry in pre- andpost-chemotherapy tumor biopsies (n=32) and compared with the tumor responseand the patients? follow-up. BRCA1 expression increased in tumor cells after DOX/EPIadministration whereas CtIP expression significantly decreased afterchemotherapy. No associations were found between DNA repair proteins expressionand the clinical and pathological response to neoadjuvant chemotherapy.However, BRCA1 expression (˃10% of tumor cells) in the post-chemotherapybiopsies was associated with better DFS and OS (P<0.001 and P<0.05,respectively). Our results indicate that BRCA1 expression may be a usefulprognostic marker in breast cancer patients treated with neoadjuvant anthracycline-basedchemotherapy followed by cyclophosphamide, methotrexate and 5-fluorouracil.