genetics module 16

Exposure to which chemicals or foods increases cancer risk? Check all that apply.

-Insecticides-Herbicides-Fungicides-Fumigants-Cooked red meat

Mutations in a gene called RGS7 have been shown to result in an increase in anchorage independent growth (i.e. cells can grow without being connected to the extracellular matrix) and in cell migration in a certain type of skin cancer. To which stage or "strike" of cancer progression would this mutation contribute?

Invasion

RB1 and p53 are ____________ .

tumor suppressors

T/F Most cancers are the result of a single genetic change.

False

Cancer can result from a failure of __________

cell cycle checkpoint

Breast cancer is classified into four different categories based on the genes that are expressed in the cancer cells. Two of the subtypes are luminal A and luminal B. Both of these cancers start in luminal cells that line the mammary ducts. However, gene expression patterns ultimately differ between the two cancer types. What best characterizes the type of pathway that was disrupted to lead to this difference?

Cell fate pathways

Which of the following events at the cellular level can result in development of cancer?

- Activation of cancer stem cells - Increase in the proportion of stem cells within a tissue - Defective tissue repair - Dedifferentiation

Which of the following characteristics are typical of cancer cells?

- Loss of cell cycle control - Dedifferentiated - Lack of contact inhibition - Can induce blood vessel formation

oncogenes

- activation causes cancer - cancer entails a gain-of-function - activation is usually associated with a point mutations, translocation, or inversion

passenger mutation

- does not cause cancer - occurs in cancerous and noncancerous cells - number of mutations increases with the patients age

tumor suppressor genes

- inactivation causes cancer - cancer entails a loss-of-function - often inactivated by a point mutation or deletion

You perform a karyotype on cells from a cancer sample and you see a normal chromosomal array (44 autosomes and 2 sex chromosomes). However, when you perform gene expression profiling, you see that gene expression in the cancerous tissue is different than in adjacent normal tissue. Select scenarios that are consistent with your observations. Check all that apply.

- point mutations have changed the expression patterns of several transcription factors in the cancer cells. -Epigenetic changes throughout the genome have changed the expression patterns of genes. -A chromosomal inversion has inactivated a tumor suppressor.

Select the passenger mutation from the list below.

A silent mutation in Rb

The drug bevacizumab is used to treat a number of different cancers including colorectal cancer, lung cancer, and breast cancer. This drug is a VEGF inhibitor. In what way do you predict bevacizumab affects cancer?

Bevacizumab inhibits angiogenesis.

Select the example that shows the interplay between environmental and genetic factors in cancer.

Certain mutations in the genes that encode the cytochrome P450 complex lead to poorer detoxification of cigarette smoke, and thus greater cancer risk.

CD133 is a cell surface molecule that is commonly used to identify cancer stem cells in certain types of tumors. CD133 is typically lost from cells

at the late progenitor stage.

A tumor suppressor gene mutation that causes cancer is usually a ____________ .

deletion

Activation of a proto-oncogene into an oncogene could occur due to a mutation or a change in the ____________ of the wild-type gene.

expression

T/F All tumors are cancerous.

false

T/F most cases of cancer arise from inheriting a cancer susceptibility allele from a parent

false

T/F: A mutation in the APC gene occurs commonly in colon cancer. Everyone who inherits the APC mutation will develop colon cancer

false

T/F: Cancer begins when a cell divides less frequently than it should.

false

T/F: Chromosomes in cancer cells exist in normal numbers

false

T/F: Duplication of a chromosome in a cancer cell reduces the copies of an oncogene.

false

T/F: Most cases of cancer are caused by normal chromosomes

false

T/F: Oncogenes cause cancer when they are inactivated.

false

Cancer susceptibility is passed onto future generations when a(n) _____________ mutation has occurred.

germline

Genes that normally stimulate cell division when it is appropriate are called ____________ .

proto-oncongenes

driver mutation

provides the selective growth advantage to a cells - known to occur in about 200 genes

____________ is a method of treatment that causes adverse effects by harming healthy cells.

radiation

A mutation that occurs in cells that do not develop into gametes is called a(n) _________ mutation.

somatic

Sporadic cancer is due to __________ mutations.

somatic

The oldest approach to treating cancer is _____________

surgery

Cancer cells often have longer telomeres due to reactivation of the enzyme ___________

telomerase

Traditional treatments for cancer, such as radiation and chemotherapy, are effective because _________

they kill rapidly dividing cells

A fusion protein can be produced due to the ____________ of a proto-oncogene to a site next to another gene.

translocation

T/F Somatic cells may develop mutations in cancer-causing genes

true

T/F: A mutation present in all stages of a tumor acts early in the disease process

true

T/F: Chromosomes in cancer cells may bear translocations

true

T/F: Chromothripsis shatters several chromosomes and may kill the cell- or trigger cancer.

true

T/F: The older a tumor is, the more genetic changes it will have

true

T/F: The process of a tumor spreading is called metastasis.

true

T/F: Translocations that join parts of non-homologous chromosomes turn genes into oncogenes

true

________________ is targeted based on genetic information.

tryosine kinase inhibitor