One of the main focus of the group is about Lynch syndrome (LS), that is the most common genetic predisposition for hereditary cancer but remains underdiagnosed. Large prospective observational studies have recently increased understanding of the effectiveness of colonoscopic surveillance and the heterogeneity of cancer risk between genotypes. The need for gene- and gender-specific guidelines has been acknowledged by our efforts from the Prospective Lynch Syndrome Database (PLSD) which allowed to update the clinical management of LS. Our work has been to conduct an international and multicenter prospective observational study using independent test and validation cohorts of LS. We provided for the first time, larger numbers that allowed to derive more precise risks estimates for cancer in LS categorized by gene and gender.