final - familial colon cancer example

Question 1

what are some characteristics of familial adenomatous polyposis (FAP) syndrome?

Answer 1

• adenocarcinoma with mixed glandular and neuroendocrine components
• multifocal adenocarcenomas
• tubular adenomas

Question 2

what gene causes the defect in FAP?

Answer 2

APC

Question 3

what is the faulty process behind hereditary non-polyposis colon cancer (HNPCC)?

Answer 3

• defects in DNA mismatch repair

Question 4

stepwise progression of FAP

Answer 4

• germ-line inactivation of allele
• lots of adenomas because in every crypt
• multiple independent mutations
• carcinoma after 20 years

Question 5

stepwise progression of sporadic colon cancer

Answer 5

• multiple independent mutations
• adenoma
• multiple independent mutations
• carcinoma

Question 6

stepwise progression of HNPCC

Answer 6

• multiple independent mutations
• adenoma
• germ-line + somatic inactivation of allele
• carcinoma

Question 7

what is important about beta catenin?

Answer 7

can initiate cell division

Question 8

how is APC related to beta catenin?

Answer 8

• normal APC regulates amount of free beta catenin
• mutated APC form makes protein that can’t bind beta catenin so beta catenin builds up in cell
• polyps form