Cancer is
the rapid proliferation of abnormal cells that cause biochemical defects
Benign Cancer
doesn’t spread to surrounding cells
Malignant Cancer
invades surrounding tissue
How do we know that cancer is a genetic disease?
susceptibility to cancer can be inherited; this doesn’t mean that an individual WILL get cancer
Avoidable Causes of Cancer
DNA Damaging agents (UV & Chemical mutagens) & viruses
Why does cancer risk increase with age?
because as cells have been dividing for longer, they collect more errors in the DNA
Properties of cancer cells
- dont respond to signals that control cell division
- are immortal; dont respond to signals that trigger cell death
- genetically unstable
- lost cell cycle control
Cell cycle checkpoints
G1, G2, Spindle Assembly
Cancer causing genes
oncogenes and tumor repressor genes
Oncogenes
a mutant form of a normal gene whose presence causes cancer
Tumor Repressor Genes
a gene whose absence causes cancer
Difficulties of cancer treatment
- specificity (can also affect normal cells)
- different cancers have different underlying causes
- tumors are heterogeneous
- cancer develops resistance to the drug
