MAPK1 and neoplasm: It should also be noted, however, that there is considerable cross-talk among all of the pathways, such that Akt functions in Wnt signaling, although there is evidence to suggest that the mechanism differs between normal and tumor cells (Anderson and Wong, 2010), and the smad2 and smad3 proteins in the TGF-β pathway are activated by ERK (Hough et al., 2012).