Cancer Flashcards
What are the two types of tumour?
Malignant and benign tumour.
What are malignant tumours?
Malignant tumours are cancerous.
These usually grow rapidly and invade and destroy surrounding tissues.
What is metastasis (forming secondary tumours) of malignant tumours?
Cells do not produce adhesion molecules and so they can break off and spread to other parts of the body via the bloodstream and lymphatic system, forming secondary tumours
What are benign tumours?
Benign tumours are not cancerous.
These usually grow slower than malignant tumours.
How are primary tumours formed on benign tumours?
Cells produce adhesion molecules that makes them stick together and so they remain within the tissue from which they arise = primary tumours.
Tumours are surrounded by a capsule of dense tissue and so remain as a compact structure.
Benign tumours are often harmless, but they can cause blockages or put pressure on organs
What are the two types of gene that control cell division?
Tumour suppressor genes
Proto-oncogenes
Mutations in these genes can cause cancer.
Define methylation:
Methylation means adding a methyl (CH3) group onto something.
When may abnormal methylation occur?
Abnormal DNA methylation is common in the development of a variety of tumours.
Define hypomethylation?
Reduced methylation which may cause problems
Define hypermethylation?
Increased methylation
Most common form of abnormal methylation?
Hypermethylation
How are tumours formed?
Hypomethylation of proto-oncogenes results in them behaving as oncogenes.
This increases the production of the proteins that stimulate cell division.
As a result, cells divide uncontrollably, which causes the formation of tumours.
Why does a womens risk of developing breast cancer increase?
After the menopause the chance of a women getting breast cancer increases due to a high concentration of oestrogen due to fat cells of the breasts producing it. Once a tumour has developed, oestrogen is further increased and leads to further development of the tumour. White blood cells are also drawn to the increased oestrogen production which further develops the tumour even more.
