characteristics of cancer cells
Anchorage Independent (grow when anchored or liquid)
Insensitive to pop density
replenished telomeric shortening
block apoptosis/ pass checkpoints
How cancers spread
cancers leave tissue of origin, move thru blood stream, invade another tissue and grow (metastasis)
What causes cancers
Environment- carcinogens, UV radiation, viruses
Hereditary factors- 10-20% of all cancers
What are Proto-oncogenes/ oncogenes
proto- encode pro. that stim cell division, inhibit cell differentiation, halt death
What are tumour suppressor genes
in normal cells encode pro. that inhibit cell division
How are proto oncogenes converted to oncogenes
point mutation, gene amplification, chromosomal translocation, local DNA rearrangements, Insertional mutagenesis
P53 + RB tumor suppressor genes
P53- regulates cell cycle and function, most frequently mutated (1/2 all cancers)
RB- if the gene mutated early in life ], the pro. is inactivated and results in development of retinoblastoma cancer
Stepwise accumulation of mutations in oncogenes
- APC mutation- Early benign tumor
- KRAS mutation- intermediate benign tumor
- SMAD4 mutation- late benign tumor
- P53- localized cancer