Cancer Basics - Handorf

Question 1

Which of these are gatekeepers? Which are Caretakers?

ATM, Rb, APC, p19 Arf, BRca1, Brca2, Mlh1, p16 Ink4, Msh2, p53

Answer 1

Gatekeepers: Rb, p53, APC, p19 Arf, p16 Ink4

Caretakers: ATM, Brca1, Brca2, Mlh1, Msh2

Question 2

Does retinoblastoma usually affect one or both eyes?

Answer 2

both eyes since it is genetic and Rb is common to both

Question 3

What is familial polyposis coli? (FAP)

Answer 3

hundreds to thousands of colon polyps develop by age 20. Will develop into colon cancer if not removed. Inherited, inactivated APC (adenomatous polyposis coli) gene causes the susceptibility to cancer.

Question 4

What is p53?

Answer 4

transcription factor that induces cell cycle arrest (G1 checkpoint) in response to DNA damage. Induces apoptosis in repsonse to excessive mitogenic stimulation or if the DNA damage cannot be repaired.

Question 5

What happens when p53 is inactivated?

Answer 5

causes genome instability. If it is defective, patient has Li-Faumeni syndrome, which causes inherited susceptibility to multiple cancers. 90% develop a tumor by age 50.

Question 6

What is Li-Fraumeni Syndrome?

Answer 6

defective p52

Question 7

What is Lynch Syndrome?

Answer 7

(Hereditary Nonpolyposis syndrome. mutation one of five DNA repair genes, which act as tumor suppressor. Can be caused by mutations in MLH1 and MSH2. Usually have normal number of chromosomes.

Question 8

What is hereditary nonpolyposis colorectal cancer (HNPCC) caused by?

Answer 8

defects in MLH1 and MSH2 or other DNA reapir genes involved in mismatch repair.