Chapter 23: Cancer Genetics

Cancer

Uncontrollable cell growth

Tumor

Accumulation of Cells

Benign

Grows slowly & does not spread

Malignant

Grows quickly & invades other tissues

Metastasis

Tumor cells induce secondary tumors, can travel throughout the body

Telomerase Activity

Telomeres shorten every time a cell divides

Lack of Contact Inhibition

Normal cells don’t grow on top of each other (known as contact inhibition)

Cyclins

group of proteins that drive the cell cycle forward

CDK (cyclin-dependent kinase)

Teams up with cyclin to attach phosphate groups to certain proteins (making them more/less active)

MPF (maturation-promoting factor)

The complex that forms when cyclin binds to its CDK partner

Knudson’s Multistep Model of Cancer

Requires several mutations

The clonal evolution of tumors

Tumor cells acquire more mutations that allow them to become increasingly more aggressive in their growing abilities

Genetic evidence for Cancer

Carcinogens, chromosomal abnormalities, inheritance

Oncogenes

mutated stimulatory genes that cause cancer

Proto-oncogenes

Responsible for basic cellular functions in normal cells; when mutated, they become oncogenes

Tumor-suppressor genes

Inhibitory genes that prevent uncontrolled cellular growth

DNA repair genes

Associated with factors that fix mutations in the DNA