Cancer Flashcards
What is cancer?
A malignant tumour
A mass of cells created by uncontrolled cell division (tumour) that can spread (malignant)
What does malignant mean?
The tumour can break off and form new tumours elsewhere in the body by undergoing metastasis
What is metastasis
Cells of the og tumour break off and travel in the blood to somewhere else and form a new tumour
So spreads
ARE Malignant tumour cells speliaised?
No they underwent dedifferentiation and became unspecialised
How do tumours kill?
Damage organ the tumour grows on/next to
Causes blockages
Exerts pressure on organs
Benign tumours
Mass of cells that undergo uncontrolled cell division but NOT metastasis so will not break off to form another tumour
Are benign tumours well differentiated?
YES they do not undergo dedifferentiation
Are benign tumours considered cancer?
NAUR
Can benign tumours still cause damage?
Yes on the organ they grow but are less risk
Proto oncogene
A normal gene that encodes for a protein that stimulates cell division (normal)
Mutation of a proto oncogene causes what?
An oncogene
Transcribed (signalling) protein of an oncogene does what?
Stimulates cell division too much so rate of cell division is too high = uncontrolled cell division = tumour
Why does an oncogene encode for a different protein than the proto oncogene?
Mutation of proto onco gene means change in base sequence so change in amino acid sequence of polypeptide so change in tertiary structure of protein that stimulates cell division = uncontrolled cell division
Tumour suppressor gene
Gene that has the normal function of coding for a protein that slows down the rate of cell division (prevents uncontrollable cell division)
Mutation of tumour suppresor gene
Changes AA sequence of signalling protein so no longer functional in slowing down rate of cell division
Increases risk of uncontrollable cell division = tumour growth
IS it uncontrollable cell division or uncontrollable cell growth?
UNCONTROLLABLE CELL DIVISION
Epigenetics effect on cancer: which factor do you need to talk about?
Methylation of DNA base sequence of genes ONLY
Increased methylation of oncogenes
Inhibit transcription of oncogene
So signalling protein that stimulates uncontrollable cell division not translated for = prevents tumour formation
Overall effect of increased methylation of oncogene?
Reduces risk of cancer
Decreased methylation of oncogenes
Increased transcription of oncogene because RNA polymerase can bind to promoter / gene
So signalling protein that stimulates uncontrollable cell division is translated for = increases tumour formation
Overall effect of decreased methylation of oncogene?
Increases risk of cancer
What could an anticancer drug be designed around?
Drug that causes Increased methylation of oncogenes so inhibits transcription of these genes
And decreased methylation of tumour suppressor genes so stimulates more transcription of these genes
Increased methylation of tumour suppressor genes
Inhibit transcription of gene because RNA polymerase can bind to promoter/ gene
So signalling protein that inhibits uncontrollable cell division not translated for, leading to tumour formation
Overall effect of increased methylation of tumour suppressor gene?
Increases risk of tumour formation
Decreased methylation of tumour suppressor gene
Gene/ promoter now available for RNA polymerase to activate/ actually transcribe gene so gene that inhibits uncontrollable cell division is translated = reduces risk of tumour formation
Overall effect of decreased methylation of tumour suppressor gene
Decreases risk of tumour formation
How does increased oestrogen concentration increase risk of development of breast cancer?
More oestrogen will bind to more transcription factors oestrogen binding site
More transcription factors bind to promoters/gene so stimulates more transcription by activating RNA polymerase more so signalling proteins that increase breast devlopment in excess = uncontrollable cell division
