Screening in GI Cancers: The Role of Genetics.

Genetic and epigenetic alterations identified in tumors of different cancer types can provide insights regarding the roles played by different cell signaling pathways in carcinogenesis. Somatic mutation profiles of GI tumors are used to guide choice of chemotherapy and can facilitate identification of individuals whose cancers arise in the setting of genetic predisposition. This review provides a framework for how clinical history, family history of cancer, and tumor genomic phenotype can be used to screen patients with colorectal, gastric, or pancreatic cancer for hereditary cancer syndromes. Early identification of individuals who carry germline mutations can affect clinical care not only for patients with cancer but also for their at-risk relatives.