Cancer 1 Flashcards
What is cancer?
disease in which an individual mutant clone of cells begin by prospering at the expense of its neighbor cells
What are some properties of cancer cells?
cells growing out of control
do not need signals to grow
release autocrine growth factor
ignore apoptosis signals
What are two heritable properties of cancer cells?
- reproduce in defiance of normal restraints on cell division and cell growth
- invade area normally reserved for other cells
How do cancer cells kill?
as a tumor grows and spreads, it squeezes or destroys blood vessels, nerves until an organ can no longer do its job
What are carcinomas?
from epithelial cells
What are sarcomas?
from connective tissue and muscle tissue
What are leukemias and lymphomas?
from white blood cells and their precursors
What are benign tumors?
adenoma- benign epithelial tumor with glandular organization
A malignant tumor of same type is _______
adenocarcinoma
What is basal cell carcinoma?
keratinocyte stem cell in skin
What is melanoma?
pigment cells in skin
What is the difference between basal cell carcinoma and melanoma?
basal cell carcinoma rarely metastasize whereas malignant melanomas metastasize widely
what mutation occurs to cause colon cancer?
mutation in APC gene (which is a tumor suppressor)
Most cancer derive from ______
single abnormal cell
What is the evidence that cancer comes from a single cell?
The Philadelphia chromosome
translocation with Chr 9 and 22
all cancer cells have same chromosomal aberration
What are the two types of carcinogens?
chemical and radiation
What is the best weapon against cancer?
early detection
How can obesity be related to more incidence of cancer?
more cells/ more chance of mutation
What is angiogenesis
formation of new blood vessels from pre existing blood vessels
What is neovascularization?
formation of new blood vessels from scratch
what does the Ames test do?
bacteria needs histidine, and salmonella will not grow without it
if cells are mutagenic, they can produce colonies of bacteria that grow without histidine
______ is the most important environmental cause of cancer
tobacco
What are the two genetic causes of cancers?
tumor supressor genes
oncogenes
What happens in a tumor suppressor gene mutation?
under activity mutation–loss of function
tumors can no longer be suppressed
What happens in a oncogene mutation?
overactivity mutation-gain of function
involves single mutation event and activation of gene causing proliferation
What are DNA maintenance genes?
subset of tumor suppressor genes, mutations involve inactivation of caretaker genes that create genomic stability
What was the first human oncogene?
Ras
What is Ras?
monomeric GTPase for signal transduction
Ras oncogenes _____ shut off by hydrolyzing GTP to GDP
cannot
What are the four mechanisms of oncogene activation?
- Deletion or point mutation
- regulatory mutation
- gene amplification
- chromosomal rearrangement
Describe deletion or point mutation for mechanism of oncogene
makes hyperactive protein
can keep protein in active state
Describe regulatory mutation for mechanism of oncogene
produce more normal protein-promotor mutation
Describe gene amplification for mechanism of oncogene
several copies instead of 1 copy-normal protein overproduced
Describe chromosomal rearrangement for mechanism of oncogene
brings new regulatory sequence that causes overproduction OR creates overreaction fusion protein
How can ligands cause cancer?
if ligands produced constitutively they cause proliferation and growth all the time (cancer cells produce own ligand–autocrine signaling)
How can receptors cause cancer?
tyrosine kinase receptors–when RTKs constitutively produced don’t even need a ligand
What does Bcl2 do?
promotes cell survival despite DNA damage
