Chapter 21a Flashcards
all forms of cancer share one characteristic
uncontrollable cell division
tumor or neoplasm
abnormal growth of cells can form a mass of tissue
benign tumor
an abnormal mass of tissue that usually remains at the site where it forms
a benign tumor can be harmful when
they interfere with the functioning of nearby tissues or inoperable (as may occur in the brain)
malignant tumor
those that can invade surrounding tissue and spread to multiple locations throughout the body; cancerous
metastasis
the spread of cancer cells from one part of the body to another
dysplasia
term used to describe the changes in shape, nuclei, and organization within tissues of precancerous cells (large irregularly shaped nuclei that contain increased amount of DNA)
carcinoma in situ
“cancer in place”
once cancer cells have left the original tumor they usually enter the __________ or _________ system
cardiovascular; lymphatic
cells of malignant tumor:
- attract a blood supply
- gain the ability to leave the other cells
- spread to distant sites (metastasize)
cancer cells:
- are greedy
- they deprive normal cells of nutrients weakening them
- can prevent cells from performing their usual functions
- can block blood vessels or air passageways
- can press on vital nerve pathways in the brain
tumor suppressor genes
- detect damage
- manage cell repair
- cell death
oncogenes
cancer-promoting genes
Cancer can also result if _____-_________ ____ are turned off or if ________ are turned on
tumor- suppressor genes; oncogenes
two types of genes usually regulate cell division:
proto-oncogenes; tumor suppressor genes
proto-oncogenes stimulate
cell division
tumor-suppressor genes ______ cell division
inhibit
p53
the tumor-suppressor gene that produces a protein that regulates another gene whose job it is to make a protein that keeps cells in a nondividing state
mutant p53
an important factor in more than half of all cancers; fails to halt cell division and initiate cell death
BRCA1 and BRCA2 proteins
Initiate DNA repair. Two tumor-suppressor gene products that play a role in breast cancer.
ras gene
product normally signals the presence of a growth factor, which stimulates cell division.
contact inhibition
if healthy cells contact a neighbor they stop dividing
apoptosis
programmed cell death; when DNA damage is too extensive to repair
cancer cells often fail to trigger ______
apoptosis
senescence
nondividing state
telomeres
pieces of DNA at the tips of chromosomes that serve as counting mechanisms that limit the number of times a cell can divide
telomerase
the enzyme that constructs telomeres
when a tumor reaches the size of about a million cells its growth will stop unless it can attract a _____ ______ to deliver the ________ it needs and to remove ______.
blood supply; nutrients; waste
cells produce a protein that prevents new blood vessels from forming in tissues
p53
normal cells are “glued” in place by special molecules on their surfaces called
cellular adhesion molecules CAMs
unanchored cancer cells can continue dividing and evade self-destruction because…
their oncogenes send a false message to the nucleus saying that the cell is properly attached.
body defense cells
natural killer cells and cytotoxic T cells
can recognize changes to identification proteins on cell membrane when they become cancerous
multiple ________ must occur and accumulate in a cell before the cells becomes cancerous
mutations
epigenome
network of chemical tags that bind to DNA and turn specific genes on or off without altering the sequence of nucleotides
mutations
changes in the sequence of nucleotides
Gene ________ and _________ interact to cause cancer
mutations and epigenetics
cancer risk factors
- viruses -tobacco use
- chemicals -carcinogens
- radiation -genetics
- age -hormones, synthetic hormones
- poor diet -lack of physical activity
- sunlight
