Optimization of a flow cytometry protocol for pd-1/ctla-4 immune checkpoints receptors detection in colorectal cancer tumour microenvironment

Considering the individual heterogeneity of the tumours, a personalized approach in oncology is crucial to design a particular dynamic treatment for the individual, from the diagnostic, to monitoring and therapy. In particular, the cellular makeup of the tumour microenvironment consists of diverse immune cells, which include tumour-infiltrating lymphocytes (TILs), as well as tumour-associated macrophages (TAMs) and tumour-associated neutrophils (TANs). These immune cells express various immune checkpoint molecules such as PD-1 and CTLA-4 that play a crucial role in modulating the colorectal cancer microenvironment, controlling the disease's development and response to therapy. Considering the huge potential of PD-1/PDL1 and CTLA-4 as actionable targets for immunotherapy in colorectal cancer as well as the advantages of the flow cytometry technique, we propose here a flow cytometry method to characterize the colorectal cancer microenvironment in terms of cells populations and their associate immune checkpoint molecular profile.