MARK2 and cancer: RAC1 has also been linked to the strongly cancer-associated kinase signalling pathways involving isoforms of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), RAC-alpha serine, threonine protein-kinase (AKT), and serine/threonine protein-kinase mTOR (MTOR) (hereafter referred to as the PI3K/AKT/MTOR pathway) [14], and Raf proto-oncogene (RAF)/mitogen-activated protein kinase kinase (MEK)/Mitogen activated protein kinase (ERK) (hereafter referred to as the RAF/MEK/ERK pathway) [12, 15].