Tumor Suppressor Genes

Question 1

Tumor Suppressor Genes

Answer 1

• Loss of function leads to increased cancer risk

- Both alleles must be lost for expression of disease

Question 2

Rb

Answer 2

• Associated Tumor: Retinoblastoma, osteosarcoma
• Gene Product: Mutation Increases E2F; blocks G1–> S phase
• Both normal RB alleles must be inactivated.

Question 3

p53

Answer 3

• Associated Tumor: Most human cancers, Li-Fraumeni syndrome
  Gene Product: Transcription factor for p21, blocks G1–>S phase
• Mediated mainly through CDK21. 

Question 4

BRCA1 & BRCA2

Answer 4

Associated Tumor:Breast and ovarian cancer

- Gene Product: DNA repair protein

Question 5

p16

Answer 5

• Associated Tumor: Melanoma

- Gene Product: None

Question 6

BRAF

Answer 6

• Associated Tumor: Melanoma

- Gene Product: B-raf

Question 7

APC

Answer 7

• Associated Tumor: Colorectal Cancer (associated with FAP)
• Gene Product: None
• Down-regulates growth promoting signals in the WNT signaling pathway, negative regulator of Beta catenin activity.

Question 8

WT1

Answer 8

• Associated Tumor: Wilms’ Tumor (nephroblastoma)

- Gene Product: None

Question 9

NF1

Answer 9

• Associated Tumor: Neurofibromatosis type 1

- Gene Product: RAS GTPase activating protein (RAS-GAP)

Question 10

NF2

Answer 10

• Associated Tumor: Neurofibromatosis type 2

- Gene Product: Merlin (schwannomin) protein

Question 11

DPC4

Answer 11

• Associated Tumor: Pancreatic Cancer

- Gene Product: DPC - Deleted in Pancreatic Cancer

Question 12

DCC

Answer 12

• Associated Tumor: Colon Cancer

- Gene Product: DCC - Deleted in Colon Cancer