MAPK3 and cancer: ColIV-mediated signalling has been shown to induce proliferation of Leydig cells through intracellular signalling molecules in active forms of focal adhesion kinase and the mitogen activated protein kinase (MAPK) 1/2 (Anbalagan and Rao, 2004) and of pancreatic cancer cells through interaction between the ColIV molecule and integrin receptors on the surface of the cancer cells (Öhlund et al., 2013).