The latter was indicated by the significant, by more than 90%, inhibition of the cancer cell-triggered phosphorylation of ERK1/2 by adenosine 5′-(α, β-methylene) diphosphate (APCP) (Figure 2), a selective inhibitor of CD73, the ecto-nucleotidase that mediates autocrine formation of adenosine [73]. This evidence concerns the gene MAPK3 and cancer.