425 Flashcards
Are mutations that cause cancer permanent?
Yes
What do mutations in oncogenes do/
Cause cell to reject normal functions one by one
Common solid tumors come from cell lines
That frequently divide
What types of cells can tumors arise from?
Any and all, including stem cells
Is cancer subject to natural selection? What type?
Yes, cells best for tumor growthP
Precancerous
Showing signs of cancer but not the full criteria
Tumor suppressor gene
encode proteins that restrain cell growth and prevent cells from becoming malignant
Oncogene
encode proteins that promote the loss of growth control and the conversion of a cell to a malignant state. Usually accelerate cell division.
proto-oncogenes,
with the potential to subvert the cell’s own activities and push the cell toward the malignant status
If genes are mutated or deleted
The protein can have an altered structure/function
If genes are duplicated
They can be synthesized to a greater degree
If genes are translocated
Proteins can be up or down regulated or combined with other proteins,
Mutations make proteins…
Less responsive to normal growth controls
Are oncogenes dominant or recessive?
Dominant
Cells won’t become cancerous if their _________ are intact
Tumor suppressor genes
How can someone have a mutated form of a tsg and not get the cancer?
Their other copy is intact
What does pRB do?
Regulates passage from G1 to S phase
Why is p53 so important?
Binds to a lot of proteins to prevent tumor growth
What does p53 do?
Alters cell cycle regulation, apoptosis, and/or senescence in response to stress. altering the expression of a large number of genes involved in cell cycle regulation, apoptosis, and/or senescence. When levels get too high (because protein doesn’t degrade) cell stops reproducing, and can either lead to repair or apoptosis/necrosis
How does p53 degrade?
MDM2
even if a “crucial” gene such as RB or TP53 is not mutated or deleted, the function of that gene
can be affected as the result of alterations in other genes whose products are part of the same pathway as the “crucial” gene.
What makes cancer susceptible to chemo/radiation?
They don’t follow pathways that’d fix their damage or kill off cells that are too badly damaged to survive
Why are cells with a mutant p53 so bad?
Won’t die when they’re damaged
Senescence
Ability to stop growth (but may or may not be metabolixally active)
