Ch6: Cancer Flashcards
how prevalent is cancer mortality?
2nd leading cause of death in US
what is the prognosis of cancer?
depends on:
- natural hx of type of cancer
- extent of spread at time of dx
- efficacy of existing therapy for that type
*colon cancer= >50% cured surgically
*breast &uterine cancers if detected early can cure w/ surgery/radiation but still large amounts of deaths
what is the survival rate of cancer?
overall 50%
what are variables relating to cancer frequency and significance?
- site of development
- age
- gender
epithelial cancers outnumber non-epithelial cell cancers:
6:1
epithelial (carcinomas)
non-epithelial (sarcoma, leukemia, lymphoma)
basal and squamous cell carcinomas of the skin account for:
40% of all cancers
99% of skin cancers
high frequency but rarely fatal bc easily detected, grow slowly, metastasize rarely and can be removed
malignant melanoma in 1% but 20% fatal
most common cancers
lung
colon
breast
prostate
uterus
skin
what is the basis for development of cancer?
genetic alterations
initiation
a cell must undergo an alteration or series of alterations to acquire autonomous growth potential
an initiated cell divides to form a discrete population of altered cells (a clone)-reversible at this point
carcinogens
agents that initiate cells to develop cancer
- physical- trauma, radiation
- chemical- cigs
- biologic agents- microorganisms/viruses
promotion
selective growth of the initiated cells
does not involve new mutations
promoter agents can affect only cells that have already been initiated
progression
acquisition of additional DNA mutations resulting in multiple clones that constitute the neoplasm
the more a cell deviates in character from analogous normal cells, the more rapidl it grows
oncogenes
code for cell growth and is what is altered in cancers
tumor suppression genes
keep oncogenes in check
transformation
process by which cells first lose important checks to their growth
regression
spontaneous disappearance of rapidly growing
preneoplastic
not firmly established; hyperplasias, metaplasias, dysplasias
three general initiating factors
chemical carcinogens
radiation
oncogenenic viruses
aflatoxin
potent chemical carcinogen in peanuts and corn due to fungi
carcinogens must be metabolized by cells to…
become an active metabolite that can interact with DNA, RNA or cell proteins
the establishment of carcinogenic effect depends on failure to repair…
DNA
retroviruses
tumor producing RNA viruses
epstein barr virus is associated with what cancer?
Burkitt lymphoma
genetic mutation
defective tumor suppressing gene;
retinoblastoma in children, types of BRCA1 and BRCA2 breast and ovarian cancers
