Cancer: Colorectal Flashcards Preview

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Flashcards in Cancer: Colorectal Deck (18)
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0
Q

What notable cell type is present in the small bowel epithelium but not in the colon?

A

Paneth cell.

1
Q

What are the types of stem cells in the small bowel and colon?

A

(1) position +4 cells (quiescent)

2) columnar basal cells (active

2
Q

J: This refers to an area of self-limited hyper proliferation in the small bowel or colonic epithelium.

A

What is an aberrant crypt focus?

3
Q

What oncogenes are associated with colorectal cancer?

A

(1) K-ras
(2) myc
(3) src

4
Q

What tumor suppressors are associated with colorectal cancer?

A

(1) APC
(2) p53
(3) DPC4
(4) DCC
(5) MCC
(6) beta-catenin

5
Q

What genetic lesion is the initial insult in most sporadic colon adenomas and carcinomas?

A

Inactivation of APC.

6
Q

Which gene is mutated in familial adenomatous polyposis?

A

APC.

7
Q

What ultimately results from normal Wnt signaling?

A

(1) increased, controlled proliferation

(2) decreased apoptosis

8
Q

What are some genes that are particularly susceptible to mutation when there is a mismatch repair deficiency?

A

Genes having a polyA tail: TGFBRII, Bax, MSH6.

9
Q

Does a mismatch repair deficiency cause cancer?

A

Not really, it allows mutations to regulatory genes to persist which can lead to cancer.

10
Q

How does the expression of COX-2 change in colorectal cancer?

A

It increases, promoting tumor growth and survival.

11
Q

What profile is at increased risk of colorectal cancer?

A

An aging individual with a high-fat, low-fiber diet, IBD, and a personal or familial history of CRC or adenomas.

12
Q

What is the average age of onset of polyps in FAP?

A

16.

13
Q

Where are extra colonic tumors likely to develop in FAP?

A

(1) upper GI
(2) connective tissue (desmoid)
(3) bone (osteoma)
(4) thyroid
(5) brain
(6) skin

14
Q

What is Gardner’s syndrome?

A

A variant of FAP that includes extraintestinal lesions:

(1) desmoid tumors
(2) osteomas
(3) supernumerary teeth
(4) sift tissue skin tumors
(5) CHRPE

15
Q

Where tumor most commonly found in Lynch syndrome?

A

The proximal colon.

16
Q

What extra colonic cancers are seen in individuals with Lynch syndrome?

A

(1) endometrium
(2) ovary
(3) stomach
(4) urinary tract
(5) small bowel
(6) pancreas
(7) bile ducts
(8) CNS
(9) sebaceous skin tumors

17
Q

What are accepted methods for screening for colorectal cancer?

A

(1) fecal occult blood testing
(2) fecal immunochemical testing
(3) flexible sigmoidoscopy
(4) colonoscopy
(5) barium enema