cancer - a genetic disease Flashcards
(19 cards)
what are quantitative mutations?
increased amounts of product
what are qualitative mutations?
altering the gene product to make it constitutively active
what are the three main mechanisms of gene changes to activate oncogenes?
point mutations
chromosomal rearrangements
gene amplification
give an example of an oncogene activated by a point mutation
Ras
what is the mutation that occurs in bladder cancer and what does it cause?
GGC –> GTC in H ras
Glycine –> valine
Ras is permanently switched off bc GTP is hydrolysed slowly
what are the forms of ras?
N H K
what does c-myc do?
initiation factor that regulates the synthesis of progression proteins through the cell cycle
what is Burkitt’s lymphoma?
distended and swollen jaw - affects ovaries, kidneys, breasts and ileum
what is the mutation that leads to Burkitt’s lymphoma?
translocation between cmyc (chromosome 8) and IgH promoter region on chromosome 14
what does the mutation cause in Burkitt’s lymphoma?
overproduction of cyclins so theres progression through the cell cycle
what is bcl-2?
anti-apoptotic protein
what is Bax?
pro-apoptotic protein
how do bcl-2 and Bax exist in normal cells?
as heterodimers
what happens in excess Bax?
apoptosis
what happens in excess bcl2?
immortalised cell
what does the upregulation of bcl-2 cause?
leukemias
non-hodgkin lymphomas
solid tumours e.g. small cell lung cancer
(B cell lymphomas)
what does over-expression of HER2 cause?
breast cancer
what happens to the GFRs in overexpression of the receptors?
receptors will dimerise spontaneously at the membrane in the absence of the ligand
what type of a receptor is the androgen receptor?
nuclear receptor
