8A Cancer Flashcards
What can mutations cause in terms of cancer
uncontrolled cell division which can lead to tumors
What is a tumor
a mass of abnormal cells as a result of uncontrolled cell division
two types of gene that control cell division
tumor suppressor genes and proto-oncogenes
How are tumor suppressor genes inactivated
by a mutation in the DNA sequence
What do tumor suppressor genes do
stops cells dividing and sometimes cause them to self destruct
What happens when tumor suppressor genes are inactivated
the protein that stops cells dividing uncontrollably is not produced
What happens if a mutation occurs in a proto oncogene
then the effect is increased which can make cells divide uncontrollably resulting in a tumor
describe malignant tumors
cancerous tumors that divide rapidly, and go onto to invade other cells and spread by metastasis
Describe benign tumors
non cancerous tumours which grow slower than malignant tumours are often harmless
How can benign tumours damage the body
they can cause blockages and put pressure on organs, some can also become malignant
How do tumors differ from normal cells
They have an irregular shape
They have a larger and darker nucleus
They divide more frequently
They have different antigens on their surface
They don’t respond to growth regulating processes
What is methylation
adding a methyl group to something
what can abnormal methylation of cancer related genes cause
tumor growth
What is too much methylation called
hypermethylation
What is too little methylation called
hypomethylation
What happens when tumor suppressor genes are hypermethylated
the genes are not transcribed so the proteins they produce to slow cell division are not made so cells are able to divide uncontrollably and tumors are formed
What happens when proto-oncogenes are hypomethylated
this causes them to act as oncogenes increasing the production of proteins that encourage cell division this causes cells to divide uncontrollably causing tumours to form
What can increased oestrogen lead to
increased increased risk of breast cancer
Why can oestrogen stimulate breast cancer
it can cause breast cells to divide and replicate which increases the chances of mutations occurring and cells turning cancerous
Research also suggests that oestrogen is able to introduce mutations directly into the DNA of certain breast cells increasing the chance of the cells becoming cancerous
