MARK2 and cancer: In addition, in hamartomatous polyposis syndromes, such as Peutz–Jeghers syndrome (PJS) an autosomal dominant syndrome arising from germline mutations in the serine threonine kinase gene (STK11) [11], SHs have not been identified although an exceptionally high rate of extracolonic cancers in patients with PJS including gastric (29 %), small bowel (13 %), pancreatic (36 %), breast (54 %), ovarian (21 %), lung (15 %), cervical (10 %), and uterine/testicular (9 %) [12] and many other benign lesions [13] were reported.