Cancer marked assignment

Full Name: Civics group: 21S Index no.: Date: Core Idea 2: Genetics and Inheritance Cancer Marked Assignment – Peer marking Describe the development of cancer as a multi-step process. 1 Loss of function mutation of tumour suppressor gene ; 2 mutated tumour suppressor alleles behave like recessive alleles / mutations must affect both/two alleles in a cell’s genome to produce abnormal /non-functional (defective) tumour suppressor protein 3 whose protein products are unable to arrest arrest of cell division or repair DNA in response to DNA damage or trigger apoptosis ; 4 Gain-of-function mutation of proto-oncogene ; 5 oncogenes behave as dominant alleles / only need one mutated allele to produce abnormal protein ; 6 lead to over-stimulation of the cell cycle / cell keeps dividing ; 7 This allows for subsequent accumulation of many other mutations ; 8 Cells will be able to progress through the cell cycle checkpoints unchecked; 9 Some mutations may cause activation of telomerase gene ; Telomerase enzyme prevents the shortening of the chromosome ends / cell can continue to divide indefinitely ; 10 Some mutations cause a loss of ability to differentiate ; 11 Some mutations cause cells to no longer exhibit anchorage dependence / loss of cell adhesion ; 12 Some mutations cause a loss of contact inhibition / density-dependence (and cells do not stop dividing) ; These accumulation of mutations may results in the formation of benign tumours ; 13 Mutations can also lead to angiogenesis / formation of new network of blood vessels to the cancer cells ; Blood vessels provide the cancer cells oxygen and nutrients for growth and to remove any waste products ; 14 Angiogenesis and some mutations allow metastasis to occur / cancer cells are able to break loose and travel in the bloodstream and invade other tissues to form secondary tumors At this point, the tumour is considered malignant. 8