The STK11/LKB1 gene was identified when germline heterozygous mutations in the p13.3 region of chromosome 19 were revealed as the causal mutation in Peutz–Jeghers Syndrome (PJS), an autosomal dominant disorder characterized by the development of benign gastrointestinal hamartomas, and were associated with the early onset of cancer [3,4]. This evidence concerns the gene STK11 and Peutz-Jeghers syndrome.