3. Cancer Flashcards
What are acquired mutations
Mutations that occur in individual cells after fertilisation ( in adulthood)
If these occcur in genes that control rate of cell Divsion ( by Mitosis) it can cause uncontrolled cell divsion
Causing tumour - mass of abnormal cells
what are cancers
Rumour that invaded and destroyed surrounding tissues
What 2 types of gene that could control cell divson called ?
Tumour suppressor genes
Proto - oncogenes
Mutations in these genes can cause cancer
Tumour suppressor genes
When functioning normally tumour suppressor genes slow down cell divsion by producing proteins that stop cells dividing or cause them to self destruct (apoptosis)
If mutation occurs here then the gene will be inactivated.
Protein it codes for isn’t produced and the cells divide uncontrollably resulting in tumour
What is apoptosis ?
Programmed death
Damaged cells / or infected reach end of functional life - destroyed
Proto oncogenes
when functioning normally proto- oncogenes stimulate cell divsion by producing proteins that Make cells divide.
If mutation occurs here the genes can become overreactive and it stimulates the cells to divide uncontrollably so rate of division increases - tumour
What is mutated proto- oncogene called?
Oncogene
Name 2 different cancerous rumours
Malignant tumours
Benign tymours
Malignant tumour
Cancers.
Grow rapidly and invade / destroy surrounding tissues.
They can break off the tumour and spread to other parts of the body in the bloodstream and lymph system
Benign tumours
Not cancerous
Grow slower than making emend tumours
Covered in friborous tissue that stops cells invading other tissues
Harmless but can cause blockades and put pressure on organs
Can become malignant
How do tumour cells differ from normal cells?
Nucleus larger and darker
Irregular shape
Don’t produce all proteins needed
Different antigen
Divide by mitosis more frequently
What 3 factors are thought to lead to growth of tumours ?
Abnormal methylation of dna and increased exposure to oestrogen
What does methylation mean?
Adding methyl group onto something
Why is methylation needed ?
Regulates gene expression - controls whether or not gene is transcribed and translated
Key in body
When does methylation become a problem ?
Too much - hypermethylation
Too little - hypomethylation
Tumours can grown from abnormal methalatuon of cancer related genes
What happens when tumour suppressor genes are hypermethylated ?
Genes aren’t transcribed
So protein they produce to slow down cell division aren’t made.
Cells divide uncontrollably by mitosis and tumours can develop.
What happens when hypomethylation or proto oncogenes occurs ?
Causes them to act as oncogenes
More production of protein that encourageAge cell division
Stimulates cells to divide uncontrollably- formation of tumours
Increased exposure to oestrogen may be the result of what ?
Starting menstratuon earlier than usual
Starting menopause later than usual
Or oestrogen containing drugs
Name 3 ways oestrogen can contribute to development of some Breast cancers ?
- stimulate certain breast cells to divide and replicate. More divisions taking place means higher chance of mutations occurring and so increases change of cancerous cells
- stimulates divsion meaning if cells do become cancerous their rapid replication could be further assisted by oestrogen - tumour quicker
- can introduce mutations directly into dna of breast cells - increases chance of cancerous cells
What does HRT stand for ?
Hormone replacement therapy
Increase oestrogen levels in some wowmene in order to treatment symptoms caused during menopause
