FACS analysis demonstrated that tumor-infiltrating CD8+ T cells from tumors subjected to Axl inhibition by either R428 or SGI-7079 had a prominent induction of PD-1 expression on their surface, consistent with the increased activation phenotype of these cells described above (Figure 6A); PD-1 expression on tumor-infiltrating CD4+ T cells also increased after Axl inhibition whose amount, however, remains low in comparison to CD8+ cells. This evidence concerns the gene CD4 and neoplasm.