Cancer: Colorectal Flashcards
What notable cell type is present in the small bowel epithelium but not in the colon?
Paneth cell.
What are the types of stem cells in the small bowel and colon?
(1) position +4 cells (quiescent)
2) columnar basal cells (active
J: This refers to an area of self-limited hyper proliferation in the small bowel or colonic epithelium.
What is an aberrant crypt focus?
What oncogenes are associated with colorectal cancer?
(1) K-ras
(2) myc
(3) src
What tumor suppressors are associated with colorectal cancer?
(1) APC
(2) p53
(3) DPC4
(4) DCC
(5) MCC
(6) beta-catenin
What genetic lesion is the initial insult in most sporadic colon adenomas and carcinomas?
Inactivation of APC.
Which gene is mutated in familial adenomatous polyposis?
APC.
What ultimately results from normal Wnt signaling?
(1) increased, controlled proliferation
(2) decreased apoptosis
What are some genes that are particularly susceptible to mutation when there is a mismatch repair deficiency?
Genes having a polyA tail: TGFBRII, Bax, MSH6.
Does a mismatch repair deficiency cause cancer?
Not really, it allows mutations to regulatory genes to persist which can lead to cancer.
How does the expression of COX-2 change in colorectal cancer?
It increases, promoting tumor growth and survival.
What profile is at increased risk of colorectal cancer?
An aging individual with a high-fat, low-fiber diet, IBD, and a personal or familial history of CRC or adenomas.
What is the average age of onset of polyps in FAP?
16.
Where are extra colonic tumors likely to develop in FAP?
(1) upper GI
(2) connective tissue (desmoid)
(3) bone (osteoma)
(4) thyroid
(5) brain
(6) skin
What is Gardner’s syndrome?
A variant of FAP that includes extraintestinal lesions:
(1) desmoid tumors
(2) osteomas
(3) supernumerary teeth
(4) sift tissue skin tumors
(5) CHRPE
