Soluble sFas, sFasL, sPD1, and sPDL1 Analyses in the Peripheral Blood of Locally Advanced Breast Cancer Patients Before and After Neoadjuvant Chemotherapy.

Background: Neoadjuvant chemotherapy (NAC) is currently widely indicated for treatment of breast cancer (BC), due to several advantages that include early introduction of systemic therapy, determine drug's efficacy, potential to reduce both the tumor volume of the primary tumor and regional lymph nodes, reduction in the extent of surgery in the breast and axilla, evaluation of the pathological response, and rescue therapies in specific cases. Several studies have demonstrated better long-term outcomes among patients who achieve pathologic complete response (pCR) than those with residual tumor (non-pCR). The association between pCR and long-term outcomes is strongest among HER2+ and triple-negative breast cancer (TNBC). Therefore, evaluating the efficacy of chemotherapy in real time is an important issue.

Methods: Between 2016 and 2018, a cohort carried out of 37 patients with locally advanced BC: 21 women with TNBC and 16 HER2+ submitted to NAC.

Results: High levels of sPD1 and sFas in the plasma of TNBC and HER2 patients compared to the controls (p < 0.05). Low levels of sPDL1 in HER2+ patients with pCR compared to non-pCR (p = 0.021). In paired analysis, statistical differences of sFasL levels in TNBC and HER2+ patients before and after NAC (p = 0.0065 and p = 0.041, respectively), and in sFAS levels in HER2+ patients before and after NAC (p = 0.0071).

Conclusion: The present study suggests that soluble sFas, sFasL, sPD1, and sPDL1 levels were apoptosis-related markers with potential predictive value of response to neoadjuvant chemotherapy in patients with TNBC and HER2+ breast cancer.