Cancer 1 + 2 Flashcards

1
Q

Two types of genes are involved in genetic causes of cancer. What are they?

A

Oncogenes and tumor suppressor genes.

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2
Q

Overactivity of ___, from a single mutation (dominant) event causes cell proliferation and gain of function.

Underactivity of ___, caused by two mutations (recessive) leads to loss of function and potentially cancer.

A

oncogenes.

tumor suppressor genes.

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3
Q

A third group of genes play a role in cancer as well. These genes, ___, are a subset of tumor suppressor genes.

A

DNA maintenance genes, which include DNA repair genes, checkpoint genes, etc.

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4
Q

The first human oncogene discovered was ___, and it is a monomeric ___ for signal transduction.

A

Ras.

GTPase.

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5
Q

Activation of ___ (normal genes required for cell division/growth), when hyperactivated or over-expressed, can become oncogenes to drive cell proliferation.

A

proto-oncogenes.

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6
Q

What are the 4 mechanisms of oncogene activation?

A
  1. Deletion or point mutation: makes hyperactive protein in normal amounts (Ex: Ras 12 Gly to Val: keeps Ras protein in active state)
  2. Regulatory mutation: produces more protein.
  3. Gene amplification: multiple gene copies = protein overproduced.
  4. Chromosomal rearrangement: protein overproduced.
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7
Q

The Bcl2 locus on chromosome 18 undergoes a reciprocal translocation with part of chromosome 14. Bcl2 is now under control of Ab Heavy chain gene, very active in B cells. This prevents apoptosis of damaged cells because instead of making ___, the cell makes a lot of Bcl2.

A

antibodies.

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8
Q

What are the two major categories of tumor suppressor genes, and list a few examples.

A
  1. proteins that normally restrict cell growth and proliferation. (Cell cycle inhibition proteins like Rb, CKI, proteins that promote apoptosis like caspases)
  2. proteins that maintain integrity of the genome. (Checkpoint control proteins like ATM, ATR).
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9
Q

40% of retinoblastoma is familial. How many eyes are affected?

60% of retinoblastoma is sporadic. How many eyes are affected?

Is retinoblastoma dominant or recessive?

A

familial = both eyes.

sporadic = one eye.

recessive.

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10
Q

For familial (hereditary) Rb, ___ occurs from a somatic event that eliminates the one good copy of the gene, allowing the tumor to form.

For ___ Rb, you start with 2 normal genes and need a two-hit mutation to cause a tumor.

A

loss of heterozygosity (LOH).

sporadic.

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11
Q

Rb normally inhibits E2F and cell division. ___ of Rb inactivates Rb and does not allow it to bind to E2F.

A

Phosphorylation.

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12
Q

For colorectal cancer, a colonoscopy can detect small, protruding benign tumors called polyps, aka an ___. The polyp is a precursor of cancer.

A

adenoma.

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13
Q

40% of colorectal cancers have a point mutation in ___. 60% of colorectal cancers have an inactivating mutation of __.

Another important mutation in colorectal cancer involves the ___ gene, found in more than 80% of cases.

A

K-Ras.

p53.

Apc.

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14
Q

Chemotherapy affects rapidly dividing cells. List some of the side effects that can occur by these cells being affected from chemotherapy.

A

loss of hair (hair follicles), nausea (stomach-lining), anemia and immune dysfunction (blood-producing cells)

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15
Q

In CML, a reciprocal translocation occurs between chromosomes 9 and 22, causing fusion of these two proteins __ and __.

This combination protein makes highly active __, which is inhibited by Gleevec, and cell proliferation.

Gleevec takes place of ___ on Bcr-Abl.

A

Bcr and Abl.

tyrosine kinase.

ATP.

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16
Q

Bcl2 is a ___ while p53 is a ___.

A

proto-oncogene.

tumor suppressor.

17
Q

T/F: In order to prevent drug resistance, cancer patients are treated with drugs simultaneously.

A

True.

18
Q

Normally, leukemia patients have an active oncogenic kinase. ___ blocks this oncogenic kinase activity.

A

Gleevec.