In contrast with the evidence reporting an anti-tumor activity of ERK1/2 inhibitors, it is noteworthy that they may have deleterious consequences in specific cell types, such as peripheral blood monocytes [84], skin squamous cancer cells [85], and colorectal cancer cells [86], where ERKs physiologically induce senescence by impairing telomerase activity. This evidence concerns the gene MAPK3 and colorectal cancer.