Flashcards in 18. Molecular Hallmarks of Cancer Cells Deck (12):
what are the types of tumour suppressor genes?
what is the role of gatekeepers?
play important roles in regulating normal growth
1. negative regulators of the cell cycle and proliferation
2. positive regulators of apoptosis
3. positive regulators of cell differentiation
what is the role of caretakers?
maintain genetic stability
include DNA repair genes and those that control the accuracy of mitosis
what effected carcinogens have on tumour suppressor genes?
induce molecular abnormalities in TSGs that cause reduced/lack of protein expression or inactivation of protein
need 2 hits to inactivate the TSG
epigenetic inactivation is also possible by hypermethylating the promotor gene
examples of familial cancer syndromes caused by problems in gatekeeper genes
examples of familial cancer syndromes caused by problems in caretaker genes
familial brest cancer
what is the function of proto-oncogenes?
promote cell proliferation, survival, angiogenesis and negative regulation of apoptosis
what are oncogenes?
mutated proto-oncogenes, with increased gene expression
only 1 copy of the gene needs tp be activated to induce a gain of function. mutated gene is dominant to the other normal parental gene
what are the effects of oncogenes on cells?
increased levels of cell proliferation, survival, angiogenesis and inhibition of apoptosis
what are the mechanisms of oncogene activation?
translocation of a photo-oncogene from a low transcriptionally active site to an active site
point mutation - substitution of a single base pair can alter an amino acid in the protein causing it to become hyperactive
amplification by inception of multiple copies of an oncogene
how many genetic alterations are needed to transform a normal cell into a neoplastic cell?