Epidemiology and Molecular Biology of Colorectal Cancer

Colorectal cancer (CRC) is the fourth most common cancer and the second most common cause of cancer-related death in the United States. Nonmodifiable risk factors include age, male sex, African-American ethnicity, and personal or family history of CRC or polyps (especially if these were diagnosed at a younger age), inflammatory bowel disease, or diabetes. Modifiable risk factors include poor physical activity; obesity; high consumption of red meats, processed meats, or alcohol; low total dietary intake of fiber, folate, fruits, or vegetables; and smoking tobacco. There have been several advances in diagnostic techniques, which, when combined with newly discovered genetic pathways, contribute to an expanding knowledge on which to base treatment. There are three known major molecular pathways of CRC carcinogenesis: the chromosomal instability pathway, the microsatellite instability pathway, and the serrated carcinoma pathway. Approximately 5% of all CRC cases will have a specific known genetic mutation associated with a well-characterized familial cancer syndrome with defined features. These syndromes are important to recognize distinctly as their identification facilitates surveillance and management with the aim of prevention, prophylaxis, and surgical cure. This review contains 2 figures, 3 tables and 50 references. Key words: colon cancer, colorectal cancer, familial, familial adenomatous polyposis, Lynch syndrome, microsatellite, polyp, polyposis, rectal cancer, serrated

Epidemiology and Molecular Biology of Colorectal Cancer

Colorectal cancer (CRC) is the fourth most common cancer and the second most common cause of cancer-related death in the United States. Nonmodifiable risk factors include age, male sex, African-American ethnicity, and personal or family history of CRC or polyps (especially if these were diagnosed at a younger age), inflammatory bowel disease, or diabetes. Modifiable risk factors include poor physical activity; obesity; high consumption of red meats, processed meats, or alcohol; low total dietary intake of fiber, folate, fruits, or vegetables; and smoking tobacco. There have been several advances in diagnostic techniques, which, when combined with newly discovered genetic pathways, contribute to an expanding knowledge on which to base treatment. There are three known major molecular pathways of CRC carcinogenesis: the chromosomal instability pathway, the microsatellite instability pathway, and the serrated carcinoma pathway. Approximately 5% of all CRC cases will have a specific known genetic mutation associated with a well-characterized familial cancer syndrome with defined features. These syndromes are important to recognize distinctly as their identification facilitates surveillance and management with the aim of prevention, prophylaxis, and surgical cure. This review contains 2 figures, 3 tables and 50 references. Key words: colon cancer, colorectal cancer, familial, familial adenomatous polyposis, Lynch syndrome, microsatellite, polyp, polyposis, rectal cancer, serrated