Neoplasia V

Question 1

what cancer is associated with APC? how?

Answer 1

familial polyposis coli (adenocarcinoma of colon)

Question 2

what cancer is associated with BRCA 1/2?

Answer 2

breast and ovarian

Question 3

what cancer is associated with RB?

Answer 3

retinoblastoma and osteogenic sarcoma

Question 4

what is the function of APC?

Answer 4

prevents nuclear transcription

Question 5

what is the function of BRCA 1/2?

Answer 5

regulates DNA repair

Question 6

what is the function of RB?

Answer 6

inhibits G1 - S phase

Question 7

what is the role of the WNT pathway?

Answer 7

1. controls cell fate, adhesion, and cell polarity during embryonic development 2. self-renewal of hematopoietic stem cells

Question 8

what happens following a double mutation in APC?

Answer 8

B-catenin accumulates in cell - FAP, non-familial colorectal CA and sporadic adenomas

Question 9

what are the cancer associated with RB mutations?

Answer 9

retinoblastoma, osteosarcoma, soft tissue sarcoma

Question 10

what is the function of p53?

Answer 10

inhibits G1 - S phase, repairs DNA, activates BAX

Question 11

what cancers are associated with p53 mutation?

Answer 11

lung, colon, breast CA, Li Fraumeni syndrome

Question 12

which HPV protein inhibits p53?

Answer 12

E6

Question 13

what is the VHL gene?

Answer 13

tumor suppressor gene on chromosome 3 - part of ubiquitin ligase complex

Question 14

what is the role of the VHL gene?

Answer 14

regulates nuclear transcription via HIF-1a

Question 15

what diseases are associated with VHL mutations?

Answer 15

hereditary renal cell CAs, pheochromocytomas, hemangioblastomas of CNS, retinal angiomas, renal cysts

Question 16

What is the Warburg Effect?

Answer 16

cancer cell preference for aerobic glycolysis, glucose uptake; tumors are detectable by PET

Question 17

how do carcinogens act?

Answer 17

highly reactive electrophiles - remove electrons from DNA / RNA / proteins - cause cell damage directly (without modification) or indirectly (require metabolic activation)

Question 18

is permanent DNA damage accomplished during the initiation or promotion phase of carcinogenesis?

Answer 18

initiation

Question 19

is the initiation phase of carcinogenesis reversible or irreversible?

Answer 19

irreversible (and rapid)

Question 20

does the promotion phase of carciniogenesis affect DNA? is it reversible or irreversible?

Answer 20

1. no 2. reversible

Question 21

what are the chemical involve in the initiation phase of carciniogenesis?

Answer 21

attack electron rich areas of cell (eg DNA) - chlorambucil, busulfan, melphalan

Question 22

most carcinogens are metabolized by what enzymes?

Answer 22

p450 dependent monooxygenases

Question 23

B-naphthylamine is associated with what type of cancer?

Answer 23

bladder

Question 24

what is the effect of aflatoxin B1?

Answer 24

1. potent hepatic carcinogen, causes p53 mutations and hepatocellular CA 2. mycotoxin produced by fungus aspergillus flavus (improperly stored rice, corn, peanuts)

Question 25

what type of cancer is associated with nitrosamines and amines?

Answer 25

gastric CA (converted to nitrites by bacteria)

Question 26

estrogen is a promoter of what type of tumor?

Answer 26

liver tumor

Question 27

diethyl stilbesterol is a promoter of what type of cancer?

Answer 27

post-menopausal endometrial CA, vaginal cancer

Question 28

high dietary bile acids are promoters of what type of cancer?

Answer 28

colon CA