Neoplastic 2 (Week 11) Flashcards
dominant oncogenes function
encode for proteins that are growth factors
what typically happens when dominant oncogenes mutate
overexpression/amplification of growth factor encoding
tumor suppressor genes encode for
proteins that inhibit uncontrolled cell division as well as prevention of mutations
what happens when tumor suppressor genes are mutated
lose inhibition of uncontrolled cell division
lose prevention of mutations
point mutation
change in a single base pair or a few base pairs on DNA that will change activity of proteins
(seen in pancreatic cancer and colorectal cancer)
chromosome translocation
piece of one chromosome translocated to another chromosome resulting in production of a proliferation factor or production of novel proteins that have growth or proliferation influences (CML)
gene amplification
oncogenes become inappropriately active
-multiple duplication of a small section of chromosomes causing excessive growth factor production
human epidermal growth factor receptors
receptors that have greater than normal activity when stimulated and/or more receptors than normal
-over expressed in cancers such as breast, lung, gastric, and colon
vascular endothelial growth factor
- normally present, but becomes unregulated in some cancers
- stimulate angiogenesis
- helps maintain tumors
tumor suppressor gene shutdown
mutation of cells that inhibit cell growth and prevent mutation of cells so that they no longer serve this function
-requires 2 separate mutations at the allele for this to happen
exogenous sequences
insertion of viral DNA that lead to changes in a cell making it a cancerous cell
examples of exogenous sequences
- hep B and C are associated with liver cancer
- HPV associated with cervical cancer
- epstein barr associated with lymphoma
- heliobacter pylori (causes peptic ulceration) associated with stomach cancer
heredity of cancer
- mutations that cause cancer are not heritable
- genetic predisposition to these cell mutations being easier to occur is heritable
- need genetic disposition + environmental trigger
- it is rare for mutated genes to be heritable
Examples of inherited mutated genes causing cancer
retinoblastoma Wilms tumor neurofibromatosis inherited breast cancer adenomas of colon (these are usually due to inactivated tumor supressor cells)
How does chronic inflammation lead to cancer
ongoing release of cytokines, growth factors, free radicals, and greater COX2 activity (produces more prostaglandin)
