61. Neoplasia part 2 Flashcards
Describe carcinoma in situ
very severe dysplasia, potential to become malignant and invasive, has not yet breached basement membrane
what is an environmental factor that causes cancer
carcinogen
how is carcinogenesis identified
epidemiological studies, occupational risk, direct evidence (eg chornobyl), and experimental testing
Carcinogenic risk cannot be determined by …….. alone
structural formula
what is the difference between Direct and Indirect carcinogens
direct is a carcinogen entering your body as it is (e.g. smoking)
indirect is Procarcinogens undergoing metabolic conversion into active carcinogens (nitrate into nitrosamine)
name some carcinogen requirements
resisting cell death
insensitivity to growth inhibitors
sustained angiogenesis
metastasize
invasion
how are neoplastic cells immortal (3 reasons)
Autocrine growth simulation
reduced apoptosis
telomerase activity
describe Autocrine growth simulation
abnormal expression of oncogenes and inactivation of tumor suppressors
describe reduced apoptosis
abnormal gene expression leads to inhibition of apoptosis
describe telomerase activity
in normal cells the telomeres shorten with each division. this means a cell only divides a certain amount. Telomerase prevents this
which gene encodes a protein that regulating apoptosis so when its inhibited reduced apoptosis happens
BCL-2 is a gene that encodes a protein playing a crucial role in regulating apoptosis
what gene inhibits neoplastic growth
Tp53 that encodes for p53
p53 is known as what type of gene
tumor suppressor gene
what do caretaker genes do
repair dna
what do gatekeeper genes do
stop damaged cells dividing (inhibit proliferation or induce apoptosis)
describe p53
has gatekeeper and caretaker function
“guardian of the genome”
most frequent mutated gene in cancer
what mutations can p53 go through
missense and nonsense
what does p53 binding to oncoproteins (encoded by DNA viruses) lead to
HPV
what are oncogenes
genes which drive neoplastic behavior in cells
what do oncogenes produce
oncoproteins
what are the 5 groups of onco(genes/protiens)
- growth factors
- receptors for growth factors
- DNA binding transcription factors
- signaling mediator with tyrosine Kinase activity
- signaling mediator with nucleotide binding activity
what are the 2 signaling mediators involved as oncogenes
signaling mediator with tyrosine Kinase activity
signaling mediator with nucleotide binding activity
Diploid
normal amount of DNA (2N)
Polyploidy
Exact multiples of diploid state (4N or 8N)
Aneuploidy
Inexact multiples