STK11 and cancer: AMPK expression has been found to correlate with various cancers, including ovarian, hepatocellular, pancreatic, breast, and gallbladder cancers [17-22], and a previous study found that the tumors in Peutz-Jeghers syndrome may result from deficient activation of AMPK as a consequence of inactivation of serine/threonine kinase 11, the major upstream kinase required for AMPK activation [42].