Gene expression and Cancer Flashcards
tumour
mass of abnormal cells
nucleus is larger and darker and may have more than 1
different antigens on surface (can cause an immune response)
benign tumour
doesnt cause cancer
doesn’t invade other tissues
grows slowly
cells are differentiated- specialised
malignant
often cancerous
spreads to other regions and cells break off to form new tumours
cells are undifferentiated
tumour suppressor genes
genes that slow down cell division by producing proteins that stop cell division
proteins cause cells to self destruct when cell division occurs too quickly
if the TS gene becomes mutated, the proteins aren’t made and cell division is no longer inhibited
abnormal methylation of TS
methylation- adding a methyl group which slows down transcription as the proteins cannot attach
TS gene not transcribed
if this occurs to TS genes
-can’t make proteins as TS gene is inhibited
-cell division can’t be stopped so cells divide uncontrollably
proto- oncogenes
genes that code for proteins that regulate cell growth (growth factors) and cell differentiation
when they become mutated they become overeactive + produces lots of the protein/ growth factor
always activated
uncontrollable cell division
oncogene
mutated proto-oncogene
may code for growth factor that is produced excessively
stimulates excessive cell division
cells divide uncontrollably
OR
receptor on CSM permanently activated so cell division occurs even in the absence of growth factors
oestrogen and breast cancer (theories)
oestrogen causes breast cells to divide more rapidly, increased rate of cell division, increases chance of mutations
oestrogen may stimulate already cancerous cells to divide more rapidly, helping tumours develop
oestrogen may directly affect DNA of breast cells leading to mutations + increasing the chance of becoming cancerous
different levels of oestrogen
different starts to menstrual cycle + menopause
exposed to oestrogen containing drugs
