Bio Cancer

Some genes code for proteins that control movement through the cell cycle

Mutations to these genes may result in un =restrained cell proliferation (tumor

Tumor cells continuously divide if nurtured

• Beninn
• Spherical and well encapsulated

Slow growing

Unlikely to Spread

Still can be dangerous

Ends in -oma

• Malignant
• Irregularly shaped and not well encapsulated

Fast growing

Likely to spread (metatasize)

Malignant tumor is Cancer

Cancers classified based o site of origin

- Caricoma: epithelial tissue

- Sarcoma: connective/muscle/nervous tissue

- Leukemia/Lymphoma: blood cells

Heredutary

• Carcinogen: agent thought to cause cancer
• - Mutagen: agent that mutantes DNA
• Radiation: x-rays, radon, gamma rays, nuclear
• Chemical: diet, smoking
• Viruses: HPV, H. Pylori, hepatitis
• All muturgens are caricinogens, but not all carcinogenes are mutagens

• - Nonmutagenic: may cause cancer, but not through direct mutation (alcohol)

Primary mechanism of cell cycle control

• Activated by Cyclins
• Cdks partner with different cyclins at different points in the cell cycle to promote cell division

• Cdk itself is also controlled by phosphorylation
• - P_i at one site activates Cdk, & at another site deactivates

• Cdk- cyclin complex
• - Also called mitosis- promoting factor (MPF)

Mitogens

PDGF one of the first growth factors identified

PDGF receptor is an RTK that initiates a MAP kinase cascade to signal cell division

Growth factors can overide cellular controls that otherwise inhibt cell division

Unrestrained, uncontrolled growth of cells that have the ability to metastasize

Failure of cell cycle control

Two kinds of genes can distrup the cell cycle when they are mutated

• 1. Tumor- supressor genes
• 2. Proto- Oncogenes

Normal genes involved in signal transduction pathway to signal cell division.

• Oncogene: mutated proto- oncogene that can cause cancer
• - Some encode receptors for growth factors
• if receptor is mutated "on", cell no longer needs growth factors
• Some encode signal transduction proteins

Only one copy of a proto-oncogene needed

Genes that stop cell division

Prevent Cdk/cyclin binding

• Oncogenes "step on the gas"
• Only one copy of a proto-oncogene needed

Genes that stop cell division

Prevent Cdk/ cyclin binding

• Oncogenes "step on the gas"
• Only one copy of oncogene needed
• Tumor supressors "apply the breaks"
• Both coppies of tumor suppressor need mutation