Its importance was most notable in Caenorhabditis elegans development as well as immune and cancer cells since in vivo models deficient in KSR-1 exhibited deficiencies in ERK activation in a stimulus-specific manner, resulting in resistance to inflammatory diseases and Ras-mediated cancers (Nguyen et al., 2002; Lozano et al., 2003; Fusello et al., 2006). Here, MAPK1 is linked to cancer.