Final - Cancer Genetics

Question 1

Oncogene

Answer 1

• a dominantly acting gene involved in unregulated cell growth and proliferation
• carried by viruses and associated with disease in animals

Question 2

Tumor suppressor

Answer 2

• genetic element whose loss or inactivation allows the cell to displace an alternate phenotype leading to neoplastic growth
• oncogenic potential when gene activity is lost
• recessive
• gate keeper vs. care takers

Question 3

Proto-oncogene

Answer 3

• oncogenes in humans
• have sequences that are similar to genes found in certain viruses
• they are genes present throughout the genome structurally important “housekeeping” genes involved in cell proliferation and development
• mutation in this gene converts it to oncogene-like which can lead to tumorgenesis
• Dominant

Question 4

Proto-oncogene vs. Tumor suppressor

- Proto-oncogene

Answer 4

• change/ gain of function
• dominant acting
• regular / important genes that are inherited (mutation is aquired)
• CML

Question 5

Proto-oncogene vs. Tumor suppressor

- Tumor suppressor

Answer 5

• loss of function
• recessive acting (“two-hit”)
• mutation can be inherited
• retinoblastoma, breast/ovarian cancer, hereditary nonpolyposis colon cancer (HNPCC)

Question 6

Chronic myelogenous leukemia

Answer 6

• translocation 9:22 = philidelphia chromosome
• results in loss of proper regulatory control and thus an overproduction of tyrosine kinase (protein involved in cell cycle regulation)

Question 7

Oncogene examples

Answer 7

• H-ras
• sis
• abl

Question 8

Gatekeeper gene example

Answer 8

• Rb1

Question 9

Caretaker gene example

Answer 9

• BRCA1

- BRCA2

Question 10

Cancer evolution

Answer 10

• a combination of environmental and gene affects are needed for a normal cell to become cancer cells
• there are multiple stages between normal and cancer in which multiple different mutations must occur (not necessarily in sequential order)

Question 11

Inherited mutation

Answer 11

• looking at the cancer evolution, a person wth a n inherited mutation is already one step closer to cancer and thus has one fewer mutations that is required
• depending on the inherited mutation it may be easier for the mutation to occur

Question 12

Inherited Cancer

Answer 12

• most cancers are not inherited because the exact number of mutations needed to cause cancer is specific for different forms of cancer

Question 13

Cytogenetics testing in the evolution of tumors

Answer 13

• molecular diagnostics can allow direct detection or comparison to “normal”
• karyotype and FISH can detect chromosomal anomalies associated with disease. Diagnosis, prognosis, monitor remission/relapse (Requires baseline)

Question 14

FISH

Answer 14

• flourescence in situ hybridization
• a combination of cytogenetic and molecular technologies
• uses a fluorescently labeled probe that hybridizes to a target sequence on the gene of interest