PDCD1 and neoplasm: (I–K) Flow cytometric analysis of the expressions of programmed cell death-1(PD-1) (I), PD-1 and Tim3 (J), and CTLA-4 (K) in CD8+ T cells in the tumor of Cd300afl/fl (n = 4 in I, n = 3 in J and K) and Cd300afl/fl;ItgaxCre (n = 6 in I, n = 5 in J, n = 4 in K) mice.