31 - CANCER GENETICS 1 Flashcards
what are the hallmarks of cancer
what does the src oncogene do
transforms normal cells to become insensitive to contact inhibition
what are some common inherited cancers for which genetic testing is available
what are oncogenes
positive regulators driving tumorigenesis
what are tumor suppressor genes
negative regulators that are inactivated in cancer
what are DNA repair genes
prevent mutations and maintain DNA integrity
what are proto-oncogenes
required for normal cellular function but when mutated become oncogenes and promote cancer formation
how was the tumor virus discovered
the first oncogene v-Src was isolated from Rous sarcoma virus
how do viruses cause cancer?
- a retrovirus inserts its RNA into the cell
- undergoes reverse transcription and inserts into host chromosome next to a proto-oncogene
- when the virus reproduces, the proto-oncogene is incorporated into the virus
- in repeated rounds of viral infection and reproduction, the proto-oncogene becomes rearranged, mutated or both
- it produces an oncogene that is inserted back into the host chromosome
- this leads to cancer formation when in normal cells
what is an alternative way that viruses can cause cancer
what are ways other than viral infections in which proto-oncogenes can be activated
what are receptor tyrosine kinases (RTKs)
how are RTKs coupled to Ras
what is the cascade after Ras has been activated
how is Ras activity controlled in normal cells
what happens when there has been oncogenic activation of Ras
glycine turns into valine
what type of genes are proto-oncogenes
produce factors that stimulate cell division
how are oncogenes expressed
tend to be dominant
one copy is enough to induce excessive cell proliferation
what is an example of a reciprocal translocation associated with a cancer
how does the translocation happen in Burkitt lymphoma
how can reciprocal translocation cause chronic myelogenous leukemia (CML)
philadelphia chromosome: fusion between chromosome 9 and 22 is observed in 95% of people with CML
c-Abl is a protein kinase involved in many cellular processes (proto-oncogene)
