TCGA's Study of Colorectal Carcinoma
What is colorectal cancer?
Colon and rectal adenocarcinomas are the third most commonly diagnosed cancers in both men and women and account for 9% of all cancer deaths. The colon and rectum are part of the digestive system. Cancer which forms in either the colon or the rectum are often referred to together as colorectal cancer.
In 2010, an estimated 102,600 Americans were expected to have been diagnosed with colon cancer and another 39,670 were expected to have been diagnosed with rectal cancer. In addition, 51,370 Americans were estimated to have died of colorectal cancer in 2010.1 More than 90% of colorectal cancer occurs after age 50 and the average age at diagnosis is 72.
When colorectal cancer has spread to other parts of the body, only 11% of patients will survive five years from the date of their diagnosis. Colorectal death rates have been declining since 1998, due to the increased use of screening tests that allow detection and removal of colon polyps before they progress to cancer. Additional information on colon and rectal cancer.
What have TCGA researchers learned about colorectal cancer?
- Colon and rectal cancers are a single type of cancer; TCGA was initially studying colon cancer as distinct from rectal cancer, but in multiple types of analyses, colon and rectal case results proved nearly indistinguishable.
- Tumors with hypermutation, in which the rate of genetic mutations is abnormally high because DNA repair mechanisms are disrupted, are more aggresive.
- Genes significantly mutated in colorectal cancer include novel potential drivers: ARID1A, SOX9, and FAM123B/WTX.
- Overexpression of the genes ERBB2 and IGF2, which help regulate cell proliferation, may represent therapeutic opportunities for this disease.
- Mutations in certain signaling pathways, such as WNT, are also potential targets.
1American Cancer Society. Cancer Facts and Figures 2010. Atlanta: American Cancer Society, Inc. 2010.