17 Questions
What is the function of BRCA1 in relation to DNA repair?
Homologous repair of double-strand DNA breaks
Which of the following is a consequence of Wnt signaling pathway upregulation in FAP?
Increased cell cycle progression
What is the function of TP53 in regulating cell cycle checkpoints?
Inducing apoptosis by increasing BAK/BAX
What is the consequence of Rb phosphorylation by CCND1/CDK?
Release of E2F to promote cell cycle progression
What is the function of WT1 in embryonic development?
Urogenital development
What is the normal function of VHL in normoxia?
To degrade Hypoxia-inducible factor 1 protein
What is the consequence of HIF1a protein upregulation in hypoxia?
Upregulation of VEGF and GLUT1
Which of the following is NOT a tumor associated with VHL disease?
Osteosarcoma
What is the function of APC in regulating the Wnt signaling pathway?
Degradating β-catenin
Which of the following tumor suppressor genes is most commonly associated with ovarian cancer?
BRCA1
What is the consequence of β-catenin accumulation in FAP due to APC mutations?
Upregulation of Wnt signaling pathway
Which of the following tumor suppressor genes is responsible for inducing apoptosis by increasing BAK/BAX?
TP53
What is the consequence of Rb dephosphorylation in the regulation of cell cycle?
Arrest of cell cycle at G1/S
Which of the following tumor suppressor genes is involved in urogenital development?
WT1
What is the consequence of HIF1a protein upregulation in VHL disease?
Upregulation of glucose intake
Which of the following tumor suppressor genes is associated with Li-Fraumeni syndrome?
TP53
Which of the following is NOT a tumor associated with FAP due to APC mutations?
Breast cancer
Study Notes
Tumor Suppressor Genes
- BRCA1/2: DNA repair enzymes involved in Homologous repair of double-strand DNA breaks
- BRCA1: more commonly associated with Ovarian Cancer than BRCA2
- BRCA2: higher risk of Breast Cancer in males than BRCA1
- Examples of associated cancers: Breast Cancer, Ovarian Cancer
APC/β-catenin
- APC: regulates Wnt signaling pathway by β-catenin degradation
- β-catenin: increases Wnt signaling pathway, leading to increased cell cycle and proliferation
- In Familial Adenomatous Polyposis (FAP), both APC alleles are lost, leading to increased β-catenin and subsequent cell cycle progression
- Examples of associated cancers: FAP, Colorectal Cancer, Pancreatic Cancer
TP53
- P53 protein: regulates cell-cycle checkpoint and induces apoptosis by increasing BAK/BAX
- Apoptosis: induced by increasing BAK/BAX
- Cell cycle arrest: at G1 phase by increasing p21, which inhibits CCND1/CDK, leading to Rb-E2F and no cell cycle progression
- Examples of associated cancers: Li-Fraumeni syndrome, many cancers
RB
- RB protein: regulates cell-cycle checkpoint and arrests cell cycle at G1/S phase
- Cell cycle arrest: holding E2F and preventing cell cycle progression
- Cell cycle progression: released E2F, allowing cell cycle progression when phosphorylated by CCND1/CDK
- Examples of associated cancers: Familial Retinoblastoma, Sporadic Retinoblastoma, Osteosarcoma
WT1
- WT1: transcription factor involved in urogenital development
- Example of associated cancer: Wilms tumor (Nephroblastoma)
VHL
- VHL: ubiquitin ligase component involved in normoxia and hypoxia regulation
- Normoxia: degrades Hypoxia-inducible factor 1 protein, preventing cell growth
- Hypoxia: inhibits ubiquitin ligase, leading to increased Hypoxia-inducible factor 1 protein and cell growth
- HIF1a protein products: include VEGF, GLUT1, TGF-α, and EPO, promoting angiogenesis, glucose intake, cell proliferation, and increased RBCs
- Examples of associated cancers: VHL disease (chromosome 3), Hemangioblastoma, Renal cell Cancer (bilateral), Pheochromocytoma
Tumor Suppressor Genes
- BRCA1/2: DNA repair enzymes involved in Homologous repair of double-strand DNA breaks
- BRCA1: more commonly associated with Ovarian Cancer than BRCA2
- BRCA2: higher risk of Breast Cancer in males than BRCA1
- Examples of associated cancers: Breast Cancer, Ovarian Cancer
APC/β-catenin
- APC: regulates Wnt signaling pathway by β-catenin degradation
- β-catenin: increases Wnt signaling pathway, leading to increased cell cycle and proliferation
- In Familial Adenomatous Polyposis (FAP), both APC alleles are lost, leading to increased β-catenin and subsequent cell cycle progression
- Examples of associated cancers: FAP, Colorectal Cancer, Pancreatic Cancer
TP53
- P53 protein: regulates cell-cycle checkpoint and induces apoptosis by increasing BAK/BAX
- Apoptosis: induced by increasing BAK/BAX
- Cell cycle arrest: at G1 phase by increasing p21, which inhibits CCND1/CDK, leading to Rb-E2F and no cell cycle progression
- Examples of associated cancers: Li-Fraumeni syndrome, many cancers
RB
- RB protein: regulates cell-cycle checkpoint and arrests cell cycle at G1/S phase
- Cell cycle arrest: holding E2F and preventing cell cycle progression
- Cell cycle progression: released E2F, allowing cell cycle progression when phosphorylated by CCND1/CDK
- Examples of associated cancers: Familial Retinoblastoma, Sporadic Retinoblastoma, Osteosarcoma
WT1
- WT1: transcription factor involved in urogenital development
- Example of associated cancer: Wilms tumor (Nephroblastoma)
VHL
- VHL: ubiquitin ligase component involved in normoxia and hypoxia regulation
- Normoxia: degrades Hypoxia-inducible factor 1 protein, preventing cell growth
- Hypoxia: inhibits ubiquitin ligase, leading to increased Hypoxia-inducible factor 1 protein and cell growth
- HIF1a protein products: include VEGF, GLUT1, TGF-α, and EPO, promoting angiogenesis, glucose intake, cell proliferation, and increased RBCs
- Examples of associated cancers: VHL disease (chromosome 3), Hemangioblastoma, Renal cell Cancer (bilateral), Pheochromocytoma
This quiz covers the role of tumor suppressor genes in cancer, specifically BRCA1/2 and APC/β-catenin. It explains their functions, mutations, and associated cancers.
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