Compelling experimental evidences point to monitoring of the absolute number of circulating ICOS-positive T cells as an early predictive marker of clinical activity of anti-CTLA-4 antibodies in cancer patients. Here, we report available data focusing on this issue and operative procedures to detect ICOS expression on circulating peripheral blood mononuclear cells during CTLA-4 blockade therapy.
Keywords: CTLA-4; Flow cytometry; ICOS; Immunomodulating antibodies; Solid tumors.