STK11 and polyposis: Other less known or rare diseases include polyposis, associated with MUTYH or NTHL1, which are FAP forms affecting the MUTYH or NTHL1 genes (both involved in DNA oxidative damage repair) [13,14,15], as well as Peutz–Jeghers syndrome and familial juvenile polyposis affecting the LKB1/STK11 and SMAD4 or BMPR1A tumour suppressor genes, respectively [16,17,18].