LIFE 210 Lecture Notes - Cancer Screening, Hereditary Nonpolyposis Colorectal Cancer, P53
Document Summary
Cancer is caused by loss or gain of functions. Tumor suppressor genes: loss of an inhibitory function; recessive mechanism and requires loss of both copies. Oncogenes: gain of function of a stimulatory protein; act in a dominant fashion and require only one copy to be mutated. Mutations can occur through large, global chromosomal changes or small changes to nucleotides in dna. Multiple mutations are needed for a cell to become cancerous. Cancer cells reproduce in defiance of normal restraints of cell growth/division. Mutations accumulate over time and as a result of previous mutations. Mutations that cause cells to ignore signals are common in cancer. Mutated proteins are generally in a signaling or repair pathways. Myc, ras, apc, rb, and p53 mutations are common in cancers. P16 is produced in response to cell stress to stop growth/division. Rb is a tumor suppressor and functions as a pocket protein.
