13-04-2012, 03:41 PM
Cancer
Cancer (non technical).pptx (Size: 186.58 KB / Downloads: 58)
What is Cancer?
Cancer develops when cells in a part of the body begin to grow out of control. Although there are many kinds of cancer, they all start because of out-of-control growth of abnormal cells.
Normal body cells grow, divide, and die in an orderly fashion. During the early years of a person's life, normal cells divide more rapidly until the person becomes an adult. After that, cells in most parts of the body divide only to replace worn-out or dying cells and to repair injuries.
What is the molecular basis of cancer?
Cancer is a genetic disease.
Mutations in genes result in altered proteins
During cell division
External agents
Random event
Most cancers result from mutations in somatic cells
Some cancers are caused by mutations in germline cells
Theories of cancer genesis
Standard Dogma
Proto-oncogenes (Ras – melanoma)
Tumor suppressor genes (p53 – various cancers)
Modified Dogma
Mutation in a DNA repair gene leads to the accumulation of unrepaired mutations (Loeb, 1974) (xeroderma pigmentosum)
Early-Instability Theory
Master genes required for adequate cell reproduction are disabled, resulting in aneuploidy (Philadelphia chromosome)
Problem posing
Can we understand the mechanism(s) of cancer by examining the expression patterns of genes in the cancer cell?
Can we use gene expression patterns to determine the properties of a cancer?