Lecture 7 (a): Oncogenes Flashcards
What are oncogenes?
Any genes that are associated with cancer and its growth
What are proto-oncogenes?
Genes that are typically responsible for cell growth and proliferation, usually highly regulated. In cancer these genes gain functions and become uncontrolled, leading to cancer.
What are tumour suppression genes?
Genes that function to repair DNA, or initiate apoptosis, as well as limit proliferation. These genes lose function in cancer.
What are MLH1 and MSH2 responsible for?
MLH is responsible for
How does TGF-B mutation result in cancer?
TGF-B receptors (serine-threonine receptor) have an addition mutation and a frame shift that causes a downstream stop codon. This results in a truncated receptor such that TGF-B cannot bind to it to inhibit cell proliferation.
How many mutations in general will a cell develop to become a cancer cell?
Around 6.
What mutations usually result in faster developing cancers?
DNA-repair genes. Because if disrupted, there is no system to prevent further errors in DNA.
How does cancer develop in the colon?
What adaptation does the colon have to protect against cancer?
Epithelial cells move to the top of microvilli and apoptose, shedding them.
What gene mutation is necessary in the development of colorectal cancer?
A mutation in the APC gene.
What is the most common mutation in chronic myeloid leukaemia?
The philadelphia chromosome, where the transfer of the end of chromosome 9, containing ABL gene gets transferred to chromosome 22, adjacent to the BCR. This results in the formation of BCR-ABL protein, lacking a protein cap that inactivates ABL, and thus cannot stop stimulation cell proliferation.
What does APC mutations result in?
The dysfunction of the Wnt signalling pathway, As APC is needed for the degradation of beta-Catenin in this pathway, this results in too much beta-Catenin, which stimulates cell proliferation by binding to TCF, displacing groucho.
