Neoplasia (Henry) Flashcards
a genetic disease, involving mutations and epigenetic alterations, primarily of somatic cells
cancer
what two heritable properties define cancer cells?
- they reproduce in defiance of normal restraints of cell division
- they invade and colonize other tissues
Which of these is a characteristic of malignant tumor cells? A. slow growing B. homogenous C. aneuploidy D. mitotic bodies are present E. high cytoplasmic to nucleus ratio
D
Which of these is not a risk factor for cancer? A. Low BMI B. Bad luck C. Age D. Environmental exposures E. Genetics
A
____ lesions irreversibly affect DNA sequence and karyotype.
genetic
____ changes affect gene expression and may be reversible
epigenetic
two inactivating mutations functionally eliminate these genes, promoting cell transformation
tumor suppressor genes
gene that may become active after only a single mutation event, leading to either gain or loss of function in the protein
oncogene
why is there a high level of variation in melanoma?
uv exposure causes pyrimidine dimers in DNA that are not repaired
activated fibroblasts, macrophages, and endothelial cells all contribute to the ____ microenvironment
tumor
Loss of CDK inhibitors, overexpression of Cyclin D1/CDK4 and constitutively active Ras are all ways that a cancer cell may exhibit which 'hallmark of cancer'? A. Limitless replicative potential B. Evading apoptosis C. Insensitivity to anti-growth signals D. Self-suficiency in growth signals E. Sustained angiogenesis
D
a classical tumor suppressor gene that, when hypophosphorylated, controls entry into the cell cycle via its regulation of the E2F transcription factor; it is inactivated in many tumor types
Rb
what does it mean that retinoblastoma follows a 2-hit model?
it takes the knockout of both Rb genes for a tumor to form.
the ‘guardian of the genome’ that induces cell cycle arrest to allow for DNA repair and is involved in Li-Fraumeni syndrome
P53
The Rb and P53 pathways are targets for what type of oncoproteins?
viral (HPV, Epstein Barr)
Which of these is a way that cancer cells evade death?
A. Upregulatation of CD95 B. Upregulation of Bax C. Decreased expression of APAF-1 D. Downregulation of Bcl-2 E. Downregulation of inhibitors of apoptosis
C. APAF-1 (stands for apoptotic protease activating factor 1)
Bax is a pro-apoptotic protein and Bcl-2 is anti-apoptotic. CD95 is the Fas receptor and is important for death receptor signalling.
enzyme that is often overexpressed in cancer cells that gives the cell limitless replicative potential
telomerase
why do cancers cause bleeding?
tumor blood vessels are poorly formed and leaky compared to normal blood vessels
when a tumor cell gets too far away from a blood source, upregulation of ____ is triggered, which drives the expression of ____, which causes endothelial cells to proliferate that will later become new blood vessels
HIF1α (hypoxia inducing factor); VEGF
____ metastasis occurs when cancer cells travel to other parts of the body via the blood vessels
hematogenous
loss of this protein in tumor cells is one factor that gives them an ability to invade and metastasize
e-cadherin
enzymes that degrade the basement membrane/ECM of cells, facilitating tumor cell invasion
matrix metalloproteases
cancer cells avoid ____, which is an induction of death for a cell that becomes detached from the matrix
anoikis
what is meant by the term “metastatic inefficiency”?
only a small fraction of the tumor cells shed into circulation produce a clinically detectable metastasis. this is because cells are subject to immune system exposure, anoikis and hemodynamic stress.
