Lecture 21: Cancer Immunology Flashcards
(64 cards)
The cell cycle should ___ and enter ___ in most tissues of healthy, mature animals
Slow and enter Go (cell cycle arrest)
When does the cell cycle get reactivated in healthy individuals
Injury
What are some exceptions to the slowing down of the cell cycle
Skin and hair follicles, GI epithelium, bone marrow, male gametes
What regulates normal progression through cell cycle
Checkpoints
When does cancer occur in cell cycle
When mutations accrue in the DNA of cells that allow progression of the cell cycle without regulations at checkpoints and are passed on to daughter cells
What are the two classes of genes where mutation causes deregulation of cell cycle
Tumor suppressor genes and (proto)oncogenes
What are tumor suppressor genes
Genes that produce proteins that inhibit progression through cell cycle
Includes DNA repair enzymes and signaling proteins that block cell cycle
Are tumor suppressor gene mutations dominant or recessive
Recessive
What mutation is the most common cause of cancer
Tumor suppressor gene mutations
What are (proto)oncogenes
Genes that produce proteins that promote progression through the cell cycle (ex: respond to environmental factors like injuries)
What is the result of mutations in (proto) oncogenes
Cause constitutive activation of signaling proteins in growth pathways—> oncogenes
Are (proto)oncogene mutations dominant or recessive
Dominant
Are cancer viruses like FeLV cause tumor suppressor mutations or (proto) oncogenes
(Proto)oncogenes
Describe the timeline of mutations
- Mutation inactivates suppressor gene
- Cells proliferate
- Mutations inactive DNA repair mechanism
- proto-oncogenes mutate to oncogenes
- More mutations, more genetic instability, metastatic disease
Are mutated tumor suppressor genes and oncogenes driver or passenger mutations
Driver mutations
What are mutations that don’t deregulate the cell cycle
Passenger mutations
What mutations endow the cancer with other physiological changes that give them growth advantages
Passenger mutations
What mutations can be caused by continued exposure to carcinogens or radiation or arise spontaneously due to defective DNA repair enzymes
Passenger mutations
Mutations there avoid immune destruction, tumor promoting inflammation, and genome instability and mutation are examples of what kind of mutation
Passenger mutations
Does accumulation of mutations increase or decrease antigenicity of cancer cells
Increase
What are the two ways tumor antigens can be categorized as
- Tumor specific antigens (TSA’s) or mutation associated neoantigens (MANA’s)
- Tumor associated antigens (TAA’s)
What are TSA’s or MANA’s
Unique to tumor cells, result from mutations in the exons of any gene or incorporation of oncogenic viruses
What are TAA’s
Normal proteins that are inappropriately expressed by tumors, may be overexpression of a protein or expression of embryonic or other immune privileged protein, results form mutation in gene regulatory elements
What is immune surveillance
Capacity of immune system to recognize and destroy transformed cells before they grow into tumors and to kill tumors after they are formed
