Liver kinase B1 (LKB1), a tumor suppressor encoded by serine/threonine kinase 11 (Stk11), was first associated with Peutz-Jeghers syndrome and was involved in the control of embryonic development, tissue homeostasis, stem cell function, energy metabolism, and apoptosis [9,10,11,12,13,14,15,16,17,18]. Here, STK11 is linked to Peutz-Jeghers syndrome.