Cancer: The Basics Flashcards
(29 cards)
What is a tumor?
Swelling (unregulated cell growth);
What is malignancy defined as?
The ability to metastasize
Can benign tumors kill patients?
Yes.
Cancer cells are defined by what two heritable properties?
1) Reproduce in defiance of the normal restraints on cell division
2) Invade and colonize territories normally reserved for other cells
Cancer cells usually arise from how many abnormal cells?
One
How do cancer stages develop?
Clonal Expansion
Explain clonal expansion.
Tumor progression involves successive rounds of mutation and selection, mutations gives individual cells a growth advantage over others.
How does cancer develop?
In stages
What is “immortalization”?
indefinite growth
What is “transformation”?
Independence of growth factors
What is “metastasis”?
Invasion and growth at a distant site
What are the 5 properties involved with converting cells to cancer cells?
1) Loss of regulation of cell proliferation
2) Tendency to avoid apoptosis
3) Genetic instability
4) Ability to invade
5) Ability to metastasize
What are the two types of genes critical to cancer development?
Oncogenes and TSG’s
An oncogene is what type of mutation?
Gain of function
Oncogenes act in what type of fashion?
Dominant; stimulate replication
What type of mutation does a TSG undergo?
Loss of function, acts in a recessive manner (takes two hits)
What was the first human oncogene discovered?
Ras (single point mutation)
How do proto-oncogenes become oncogenic? (3 things)
1) Mutation in coding sequence
2) Gene amplification
3) Chromosome rearrangement
What are gatekeepers?
They directly regulate cell growth, ex. Rb, p53, APC, p19 Arf, p16 Ink4
What are caretakers?
They are involved in repairing DNA damage or maintaining genomic integrity (ATM, BRCA1, BRCA2)
What is familial polyposis coli (familial adenomatous polyposis, FAP)
Hundreds of thousands of colon polyps by age 20, develop into colon cancer if not removed. It is an inherited, inactivated APC gene that causes it
What is p53?
A tumor suppressor, “the guardian of the genome”
At what cell cycle phase does p53 induce arrest?
G1 in response to DNA damage (p21 induction)
Why does p53 arrest the cell cycle?
To repair DNA damage, if it is not fixable then cell it induced apoptosis
