M3 Chapter 25 Terms - Genetics

cancer

a disease characterized by uncontrolled cell division

carcinogen

an environmental agent that increases the likelihood of developing cancer

clonal

relating to a clone or the process of cloning; i.e. a clonal population of cells is a group of cells that are derived from the same cell

benign

refers to a noncancerous tumor that is not invasive and cannot metastasize

malignant

describes a tumor composed of cancerous cells

invasive

refers to the ability of cancer cells to invade healthy tissue

metastatic

describes cancer cells that have migrated to other parts of the body

oncogene

a mutant gene that is overexpressed and thus promotes cancerous growth

tumor-suppressor gene

a gene that functions to inhibit cancerous growth

proto-oncogene

a normal cellular gene that does not cause cancer but which may incur a gain-of-function mutation that causes abnormally high expression

growth factors

signaling molecules that bind to cell surface receptors and influence cell division; can be a factor in tumor development

Knudson’s 1971 two-hit model for retinoblastoma

proposed that retinoblastoma requires two mutations to occur, where people with the hereditary form already inherit one mutation from their parents; explains why some retinoblastomas occur earlier and commonly in certain families while others occur rarely and later in age

p53

a common tumor-suppressor gene that determines if cells have incurred DNA damage - specifically double-stranded breaks; functions as a transcription factor, may activate genes involved with DNA repair, or stop the cell cycle, or signal apoptosis

rb

a tumor-suppressor gene with associated protein, negatively regulates E2F to slow cell division; if mutated, cells become more likely to divide, and potentially become retinoblastomas

genome maintenance

cellular mechanisms that prevent mutations from occurring and/or prevent mutant cells from surviving or dividing

checkpoint proteins

a protein that monitors the conditions of DNA and chromosomes and may prevent a cell from progressing through the cell cycle if an abnormality is detected

loss of heterozygosity (LOH)

the phenomenon in which a heterozygous somatic cell incurs a genetic change that inactivates the single functional allele

biomarker testing

a way to identify genes, proteins, and other substances that have become abnormal in the cancer cells of a given patient