Frequent expression of PD‐L1 on circulating breast cancer cells

• DOI: 10.1016/j.molonc.2015.05.009
• Publication Date: 2015-06-12T08:22:19Z
• Authors: Martine Mazel; William Jacot; Klaus Pantel; Kai Bartkowiak; Delphine Topart; Laure Cayrefourcq; Delphine Rossille; Thierry Maudelonde; Thierry Fest; Catherine Alix-Pa...
• Keywords: Circulating tumor cell; Immune checkpoint; Liquid biopsy

Immune checkpoint regulators such as PD‐L1 have become exciting new therapeutic targets leading to long lasting remissions in patients with advanced malignancies. However, view of the remarkable costs and toxicity profiles these therapies, predictive biomarkers able discriminate responders from non‐responders are urgently needed. In present paper, we provide evidence that is frequently expressed on metastatic cells circulating blood hormone receptor‐positive, HER2‐negative breast cancer patients. We performed western blot, flow cytometry immunocytochemical analyses demonstrate specificity PDL1 antibody used our study established immunoscores for expression single tumor cells. then selected sixteen (CTCs) using CellSearch® system found PD‐L1(+) CTCs 11 (68.8%). The fraction varied 0.2 100% individual This first report demonstrating CTCs. CTC/PD‐L1 assay can be liquid biopsy future clinical trials stratification monitoring undergoing immune blockade.