Fig. 5
From: Circadian clock: a regulator of the immunity in cancer
The processes of recognition of cancer cell, killing of cancer cell, and releasing of cancer cell antigens. T cells recognize tumor cells through surface receptors; the activation of NK cells in tumor sites directly destroys malignant cells without prior sensitization. The circadian clock, including RORγ, PER1, CRY2, and BMAL1 negatively regulate the expression of PD-1 in effector T cell. BMAL1 also negatively regulates the expression of CTLA4 and PD-L1 in effect T cells. PER1 and BMAL1 can increase the secretion of IFN-γ, granzyme B, and perforin in NK cells. When cancer cells are killed, cancer cell antigens and necrotic bodies are released in blood