Term
| What is metastasis, and which type of tumors does it pertain to, malignant or benign? |
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Definition
Tumour cell migration from one organ/tissue to establish new tumours in other organs/tissues
Malignant tumors can invade, benign cannot |
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Term
| What are the most common types of cancer in Canada |
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Definition
lung, prostate, breast & colorectal cancer
-50% of all new cancer cases! |
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Term
| What are the characteristics of cancer cells? |
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Definition
-unregulated growth
-formation of masses in culture rather than a monolayer
-disorganized skeleton
-aneuploidy
-less differentiation |
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Term
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Definition
Cylin Dependent Kinases
protein kinases which regulate the activities of other proteins in involved in cell cycle control by phosphorylation |
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Term
| What are cell cycle checkpoints? |
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Definition
A point in the cell cycle where a decision is made to either halt or continue in the cycle
-regulates transitions between G1, S, G2 & M phase |
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Term
| Where in the cell cycle is the G1/S checkpoint, and what cyclin does it require? |
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Definition
Mid G1 phase
-requires cyclin D/CDK4 |
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Term
| Where in the cell cycle is the G2/M checkpoint, and what cyclin does it require? |
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Definition
Late G2 phase
-requires cyclin B/CDK1 |
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Term
| What are tumor suppressor genes, and what kind of mutations in these genes will cause cancer? |
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Definition
-genes which suppress cell proliferation
-loss of function mutations will cause cancer |
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Term
| What are oncogenes and what kind of mutations in these genes will cause cancer? |
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Definition
-genes which promote cell division
-gain of function mutations cause cancer |
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Term
| What is retinoblastoma, and what are the two forms? |
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Definition
-inactivation of both copies of a specific gene
Familial form: one mutation is inherited while the other gene is inactivated during eye development
Sporadic form: both mutations occur during eye development |
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Term
| Describe the steps involved in regulation of the cell cycle carried out by pRB |
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Definition
1. pRB binds o E2F transcription factors early in G1, prevents transcription of target genes
2. D/CDK4 phosphrylates pRB
3. pRB releases E2F
4. Target genes are activated, cell proceeds into S phase, DNA replication is initiated |
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Term
| What are the two pathways a cell can follow if damage to the DNA damage induces p53? |
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Definition
| Cell-Cycle Arrest Pathway or Apoptotic Pathway |
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Term
| What are the steps of the cell-cycle arrest pathway? |
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Definition
1. p53 induces synthesis of p21
2. p21 inhibits CDKs
3. pRB protein remains in hypophosphorylated state
4. pRB inhibits E2F transcription factors
5. E2F proteins cannot induce transcription
6. Proteins encoded by E2F targets are not produced, cell cycle stops |
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Term
| What are the steps of the apoptotic pathway? |
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Definition
1. p53 induces synthesis of BAX protein
2. BAX antagonizes BCL-2 protein (represses apoptotic pathway)
3. Repressor can't function, apoptotic pathway is activated
4. Cell is destroyed |
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Term
| What are viral oncogenes? What are they al |
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Definition
| the viral counterpart of normal cellular oncogenes |
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Term
| What do normal cellular oncogenes code for? |
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Definition
| components of signal transduction cascade, regulating cell proliferation |
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Term
| What are transformed cells? |
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Definition
cells that can grown on soft agar & form colonies (loss of anchor-dependency & contact inhibition)
-this indicates they are cancerous |
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Term
| What is c-ras? What happens if they are stuck in the 'on' position? |
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Definition
a signaling molecule found on the inner surface of cellular membranes
-if stuck on, continuous cell division will be induced |
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Term
| Describe the steps in regulation of cell division by a normal Ras protein |
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Definition
1. Extracellular signal activates/inactivates Ras protein by phosphorylation/dephosphorylation of GTP bound to it
3. Active Ras-GTP transduces signal to nucleus
4. Signal regulates transcription of genes involved with cell division
5. Cell division occurs in a regulated manner |
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Term
| Describe the steps in regulation of cell division by a mutated Ras protein |
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Definition
1. Extracellular signal does not influence Ras protein
2. Ras protein remains active, constantly sending a signal to the nucleus
3. Genes involved with cell division are not transcribed properly
4. Cell division is not controlled (cancerous!) |
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Term
| What is a proto-oncogene? |
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Definition
| A normal gene that could undergo a mutation to become an oncogene, potential to become cancerous |
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Term
| How can translocation cause cancer? |
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Definition
| -fusion of genes from one chromosome to genes from another creates a new fusion gene, which can encode for cancer-inducing proteins |
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Term
| What happens is a proto-oncogene is translocated to a region where there are lots of promoters & enhancers? |
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Definition
| might cause overproduction of that protein |
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Term
| How can gene amplification activate cellular oncogenes? |
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Definition
| duplication of proto-oncogenes might result in overexpression of the associated protein(s) |
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Term
True or False
Most malignant tumors are due to single-gene mutations |
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Definition
| false, usually an accumulation of various somatic mutations in proto-oncogenes & tumour suppressors |
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Term
| What are characteristics of pathways that lead to malignant cancer? |
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Definition
1. Cancer cells acquire self-sufficiency in the signaling pathways for division & growth
2. Cancer cells are insensitive to signals that inhibit growth
3. Cancer cells can evade apoptosis
4. Cancer cells have potential to replicated unlimited
5. Cancer cells develop ways to nourish themselves
6. Cancer cells acquire ability to invade other tissues & form coloies |
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Term
| What is the basis for development & progression of all types of cancer? |
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Definition
| somatic mutation & accumulation of these mutations |
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