This significant immune response was, in turn, correlated to a) a relatively low expression of PD-L1 on the surface of tumor-infiltrating CD11b+ myeloid cells (Fig. 2E) and b) low expression of PD-1 in the surface of both T CD8+ and CD4+ splenic lymphocytes (Suppl. Figure 4). This evidence concerns the gene PDCD1 and neoplasm.