STK11 and Peutz-Jeghers syndrome: We have previously observed [33] that deletion of LKB1 from proglucagon-expressing cells, achieved by crossing animals bearing a glucagon promoter-driven Cre recombinase (iGLuCre) to mice with floxed LKB1alleles, leads to the development of large gastro-duodenal polyps, reminiscent of those seen in PJS [31].