HNPCC and FAP

Question 1

Genetic pathway of APC/beta-catenin

Answer 1

1. APC/beta-catenin inactivation (both alleles)
2. beta-catenin accumulation and traslocation to the nucleus
3. beta-catenin forming complex with DNA-binding factor (TCF)
4. MYC and cyclin D1genes activation (promote proliferation)
5. Additional mutations may occur in KRAS gene present in 50% of invasive colon adenocarcinomas

Question 2

MSI pathway

Answer 2

1. Missmatch repair enzymes mutation
2. Acumulation of mutations in microsatellites
3. Loss of function in TGFBR2 (II TGF-beta receptor) and BAX.

Question 3

TGF-beta, function

Answer 3

Inhibit cell cycle

Question 4

BAX protein function

Answer 4

Pro-apooptotic function

Question 5

MSI and normal mismatch repairing enzymes, possible cause? Genes involved and not involved?

Answer 5

CpG hypermetilation
+ BRAF
+ MLH1 metylation
- KRAS
- TP53

Question 6

MLH1 function

Answer 6

Repair function

Question 7

KRAS function

Answer 7

Promote growth and prevent apoptosis