Role of the expression of PD-L1 and CD47 on circulating tumor cells (CTCs) in the prediction of outcome in metastatic breast cancer (mBC) patients.

• DOI: 10.1200/jco.2019.37.15_suppl.e14045
• Publication Date: 2019-05-27T15:59:11Z
• Authors: Sofia Agelaki; Maria A. Papadaki; Panormitis G Tsou...; Despoina Aggouraki; Alexia A Monastir...; Katerina A Merodo...; Konstantina Thomo...; Chara Papadaki; Dimitrios Mavroudis
• Keywords: Circulating tumor cell; CD47; Immunosurveillance

e14045 Background: CTCs expressing innate (CD47) and adaptive (PD-L1) immune checkpoints may have enhanced potential to escape immunosurveillance. In the current study, we evaluated incidence clinical relevance of CD47 and/or PD-L1 in patients with mBC. Methods: Blood was obtained from 98 mBC before initiation first-line therapy. Triple immunofluorescence staining for cytokeratins (CK), performed on peripheral blood mononuclear cells (PBMC) cytospins 1*10 6 PBMCs per patient were analyzed using Ariol microscopy system. expression levels CK+ normalized MDA.MB.231 breast cancer as controls. Results: detected 22 out (22.4%) (total CTC No: 43; range: 1-12). High identified 41.9% 11.6% CTCs, respectively, whereas 9.1% high observed both markers. at least one marker ( ) 11.2% patients, albeit a differential distribution among triple-negative, hormone receptor-positive HER2-positive primary tumors (27.3%, 12.5% 0%, p = 0.040; Chi-square test). associated disease progression (27.8% vs 5.6%, 0.005; test) shorter PFS [median: 5.8 (4.1-7.5) 13.3 (11.4-15.2) months, 0.010; Kaplan-Meier], detection only correlated reduced OS 23.8 (5.8-41.8) 35.7 (29.9-41.4) 0.043]. Multivariate Cox-regression analysis revealed that /or predicted increased risk relapse [HR: 2.7 (95% CI: 1.3-5.7); 0.009], death 4.8 1.4-16.6); 0.011]. Conclusions: The are co-expressed subset patients. is triple-negative tumors, poor outcome could serve refinement prognosis Patients bearing this population benefit anti-CD47 anti-PD-L1 immunotherapy strategies.