AMP allosterically activates AMPK and facilitates phosphorylation of its catalytic subunit on residue Thr172 by the upstream kinase liver kinase B1 (LKB1, also known as STK11), the protein product of the tumor suppressor gene mutated in the Peutz-Jeghers cancer predisposition syndrome [17]. This evidence concerns the gene STK11 and neoplasm.