Abstract PO3-15-11: Soluble sFas, sFasL, sPD1, and sPD-L1 analyses in the blood peripheral of locally advanced breast cancer women before and after neoadjuvant chemotherapy

Abstract Assess soluble sFAS, sFASL, sPD1, and sPD-L1 levels in patients with HER2 or triple-negative (TN) breast cancer submitted to neoadjuvant chemotherapy. A prospective cohort study was performed with TN and HER2+ breast cancer patients between 2015 and 2018. Soluble levels of sFasL, sFas, sPD-L1, and sPD1 were collected before and after neoadjuvant chemotherapy (NAC). NAC regimens included a dense dose of Adriablastin and cyclophosphamide during four cycles, followed by Paclitaxel for 12 weeks. No clinical evidence of tumor in the breast and axillary lymph nodes was defined as a pathological complete response (pCR). Twenty-one women with TN (56,7%) and 16 (43,3%) HER2+ breast cancer were included. Twenty-one women (56.7%) presented complete pathological response (pCR) after neoadjuvant chemotherapy (NAC), defined as the absence of invasive disease in the breast and lymph nodes. High sPD1 and sFas levels in the TN and HER2+ patients compared to the control group (P 0.05). In paired analysis, statistical differences of sFas and sFasL levels in TN and HER2+ patients before and after NAC (P 0.05). Low levels of sPDL1 in HER2+ patients with pCR compared to non-pCR (P 0.05). High sFasL levels in TN patients with pCR compared to the non-pCR group (P 0.05). Conclusion: soluble sFas, sFas-L, sPD1, and sPD-L1 levels were apoptosis-related markers with potential predictive value of neoadjuvant chemotherapy response in TN and HER2+ breast cancer. Keywords: breast cancer; FAS receptor; Programmed death 1, HER2+, Triple negative Citation Format: Carolina Vasconcelos, Marcelo Salgado, Carlos Eduardo Anunciação, Denise Viana, Leuridan Torres, Nathália Valois Montarroyos de Moraes. Soluble sFas, sFasL, sPD1, and sPD-L1 analyses in the blood peripheral of locally advanced breast cancer women before and after neoadjuvant chemotherapy abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-15-11.