STK11 and cancer: Because LKB1 is a master kinase that can activate all 13 members of the AMPK kinase family [67], and given the overlapping substrate specificity of AMPK and its related kinases (reviewed in [33]), it seems likely that AMPK-related family members, such as MARK/Par1, may phosphorylate S245 on GIV under specific conditions and in certain cancers.