Malignant Tumors of the Large Intestine

Question 1

From where does colorectal adenocarcinoma typically arise?

Answer 1

Adenomatous polyps

Question 2

How many mutational events must accumuate before colorectal cancer typically evolves?

Answer 2

8 to 10 hits

Question 3

What are the major mutations that occur leading to colorectal caricinoma?

Answer 3

1. APC gene/Beta Catenin
2. Ras oncogene
3. DCC gene
4. p53 tumor suppressor gene

Question 4

What are the risk factors for colorectal cancer?

Answer 4

• Age
• Prior Colorectal Cancer
• Ulcerative Colitis/Crohn Disease
• Genetic Factors
• Diet

Question 5

Initial stages of tumor spread?

Answer 5

Invades lymphatic channels and initially invades lymph nodes just below tumor.

Question 6

Most common clinical sign of colorectal cancer?

Answer 6

Fecal occult blood

Question 7

Another name for hereditary nonpolyposis colorectal cancer?

Answer 7

Warthin-Lynch Syndrome

Question 8

Genetics of HNPCC?

Answer 8

TYpically germline mutation in hMSH2 or hMLH1. Second hit occurs in somatic cells

Question 9

Type of lymphoma typically found in the colon?

Answer 9

B-Cell

Question 10

What type are most cancers of the anal canal?

Answer 10

Epidermoid Carcinomas

Question 11

What is Bowen disease of the anus?

Answer 11

Squamous carcinoma in situ