PDCD1 and neoplasm: Based on these observations and on the fact that LMM3 tumor cells and tumor infiltrating cells displayed a significantly higher expression of PD-L1 than MC-C tumor cells (see above Fig. 2C, D, E and F), it was expected that the blockade of the PD-1/PD-L1 pathway might be more useful to treat LMM3 than MC-C growing tumors by unlocking the onset of an otherwise almost inexistent anti-tumor immune response.