Peutz–Jeghers syndrome polyps are polyclonal with expanded progenitor cell compartment

Peutz-Jeghers syndrome (PJS) is an autosomal dominant cancer susceptibility syndrome characterised by mucocutaneous melanin pigmentation, hamartomatous polyps, and an 18-fold increase in intestinal and extraintestinal cancer risk. 1 PJS is caused by a germline mutation in LKB1, a gene that plays a role in cellular polarity. 2 Proper cellular polarity is critical for accurate asymmetrical stem cell division. 3 The pathogenesis and neoplastic risk, if any, of hamartomatous Peutz-Jeghers polyps remain unclear. [...]we have shown that PJS polyps are polyclonal expansions, arguing against the presence of a hamartoma-carcinoma sequence in PJS.