Commentary on Lynch syndrome and related familial colorectal cancers

Hereditary colorectal cancer-prone syndromes provide ideal models for cancer control. For success, the physician must obtain a comprehensive cancer family history, which includes all anatomic sites; know the syndrome's natural history; and whenever possible be aware of likely cancer-causing molecular genetic mutations. For examples, mutations in MMR genes, namely MLH1, MSH2, MSH6, or PMS2, are exceedingly important for diagnosing the Lynch syndrome (LS), the most common hereditary colorectal cancer syndrome since, with the exception of the Muir-Torre syndrome and its cutaneous findings, phenotypic features are not present. Familial adenomatous polyposis (FAP), on the other hand, harbor striking phenotypic features, particularly multiple colonic adenomas. It is perhaps better known than Lynch syndrome due to this phenotype. Knowledge of FAP's molecular genetics, namely the APC mutation, will help in its diagnosis, particularly when there is a paucity of colonic adenomas such as observed in FAP's attenuated FAP counterpart, which is also attributable to the APC germline mutation.