PROS1 and cancer: The engulfment of dying cancer cells and their corpses can be assessed by phagocytosis assay.54,154–158 In this assay, mononuclear phagocytes (e.g. macrophages, monocytes) and cancer cells are labelled separately using non-toxic fluorescent dyes or expression of different reporter fluorescent proteins, and co-cultured after the cancer cells are treated with ICD candidates.