Interestingly, when PD-L1-knockout TRAMP-C2 cells were introduced into one side of a mouse, and WT TRAMP-C2 cells into the bilateral side after a few days, WT TRAMP-C2 cells did not develop into tumors in the mouse, indicating that to the presence of PD-L1-deficient tumor cells could generate a strong memory, even to tumor cells that release Exo-PD-L1 [9]. Here, CD274 is linked to neoplasm.