CALR and cancer: PrCR of live cancer cells has been shown to be dependent upon at least three factors: (1) chemotactic migration of macrophages/microglia cells toward the cancer cells; (2) expression of a DAMP, such as CALR, on the cell surface, which serves as a recognition signal for macrophages/microglia; (3) expression of immune checkpoints on cancer cells that block macrophage/microglia phagocytic activity, thereby preventing PrCR.