Chapter 13: Cancer

What are the causative factors of cancer?

Environmental factors: Exposure to carcinogens (eg. Tar in cigarette smoke) and ionising radiation (UV light)

Loss of immunity due to infections with certain viruses

Genetic predisposition: Inherited gene mutations

Age: Accumulation of mutations

What are proto-oncogenes?

Genes that code for proteins that stimulate normal cell division

Mutated proto-oncogenes are known as ___

Oncogenes

What do oncogenes do?

Increase the amount of a PO’s protein product or increase the intrinsic activity of PO protein product

Example of an oncogene and its effects

Mutated ras gene: results in constitutively active Ras protein that irreversibly binds to GTP and increases cell division

What are tumour suppression genes?

Genes that code for protein products that inhibit cell division and prevent uncontrolled cell division

Only copy of the tumour suppressor allele needs to be mutated for effects to be observed. T/F?

F. Both copies need to be mutated

Example of a tumour suppression gene and what it does

p53, codes for activator that activates genes involved in cell cycle arrest, DNA repair and initiating apoptosis when DNA damage is beyond repair.