Pathology of Neoplasia (22)
List 3 broad carcinogenic agents.
What type of carcinogens require metabolic conversion by cytochrome P450 in the liver?
Review some chemical carcinogens.
Review some major chemical carcinogens.
What are the 2 players in chemical carcinogenesis?
initiator: causes mutation in cell
promotor: causes clonal expansion of initiated cells through enzyme activation or by mutation
Name 2 types of radiation that can be carcinogenic.
What 2 factors determine the degree of damage due to UV radiation?
intensit of exposure and quantity
What type of radiation causes DNA damage due to formation of pyrimidine dimers?
What is the normal mechanism of repair of pyrimidine dimers?
nucleotide excision repair (NER)
List 3 cancers caused by UV radiation.
squamous cell carcinoma
basal cell carcinoma
List 3 ways in which ionizing radiation is carcinogenic.
ionization of macromolecules and generation of free radicals
Most oncogenic viruses have what type of nucleic acid?
Name 3 major DNA oncogenic viruses.
Virus that causes cervical cancer.
Virus that causes nasopharyngeal carcinoma.
Virus that causes hepatocellular carcinoma.
What type of genes are affected by oncogenic viruses?
tumor suppressor genes
Review EBV and Burkitt's lymphoma.
Name the most important RNA oncogenic virus.
How does HTLV-1 cause tumor formation?
Tax causes instability and mutation in host cell genes leading to T-cell proliferation
What bacteria is associated with B-cell lymphoma in MALT?
List 4 classes of genes affected by carcinogens.
tumor suppressor genes
apoptosis regulating genes
mutator (caretaker) genes
Normal genes that play key roles in controlling cell proliferation and differentiation.
Deregulated or altered proto-oncogenes that lead to development of cancer.
List 3 changes in gene structure that can cause activation of oncogenes.
What is the most common point mutation in human cancers?
Name the 2 chromosomes involved in translocation for chronic myelogenous leukemia.
What enzyme activity is increased in chronic myelogenous leukemia?
Amplification of which gene is involved in neuroblastoma?
Amplification of which gene is involved in breast cancer?
What type of proteins are encoded by oncogenes?
List 5 classes of oncoproteins.
growth factor receptors
signal transduction proteins
nuclear (transcription) regulatory factors
cyclin and cyclin-dependent kinases (cell cycle)
Review cell membrane diagram.
What is the most commonly mutated tumor suppressor gene?
Name a tumor suppressor gene that acts on the cell cycle (G1-S).
How many alleles must be mutated to disrupt the function of tumor suppressor genes?
both (homozygous mutation)
Tumor suppressor gene associated with hereditary neurofibromatosis.
Tumor suppressor genes associated with breast carcinoma.
BRCA 1 & 2
Tumor suppressor gene associated with adenomatous polyposis cell carcinoma.
Tumor suppressor gene associated with colon cancer.
Tumor suppressor gene associated with Wilm's tumor.
What happens to telomeres with age?
telomeres shortened with age
Gene associated with colon and pancreatic cancers.
Gene associated with B-cell lymphomas.
Review multistep carcinogenesis.