Flashcards in Neoplasia 3- evasion of apoptosis Deck (57):
_______ is the prototypic anti-apoptosis gene
how can the BCL2 gene be activated?
Can be activated by translocation from chromosome 18 to the Ig heavy chain locus on chromosome 14
(shift from chromosome 18 to 14)
what is the result of BCL2 over-expression? where is this situation usually seen?
Results in steady accumulation of cells (prevents apoptosis)
– often seen in “low-grade” lymphomas
p53 will upregulate ____, which triggers apoptosis
upregulates BAX gene
(its a balancing game between BLC2 and BAX)
Tumors cannot grow larger than 1 or 2 mm in diameter unless what occurs?
they are vascularized
how does Angiogenesis facilitates metastases ?
it provides the neoplastic cells access to the vasculature
what are the 2 major steps in invasion/metastasis?
1) invasion of the extracellular matrix
2) vascular dissemination and adhesion/homing of tumor cells
how do tumor cells invade the extracellular matrix?
1. Detachment of tumor cells from one another
2. Attachment of tumor cells to matrix components
3. Degradation of extracellular matrix
4. Migration of tumor cells
how can the distribution of tumor metastasis be predicted?
can generally be predicted by the location of the primary tumor and its vascular or lymphatic drainage
lung cancer spreading to adrenal glands, but almost never to skeletal muscle, is an example of what?
what 2 ways can organ tropism occur?
A) Adhesion molecules:
-Organ-specific endothelial adhesion molecules bind tumor cell ligands
B) receptor mediated homing:
-Chemokine receptors on tumor cells home to sites where specific ligands are readily produced
what is Hereditary nonpolyposis colon cancer syndrome? what causes it?
- familial cancers of the colon
- resulting from defective genes involved in DNA mismatch repair
- and evidence of microsatellite instability (MSI).
microsatellite instability (MSI) is seen in ____% of colon cancers
what is Xeroderma pigmentosum? what causes it?
- defective nucleotide excision repair system
- Sunlight (UV light) causes pyrimidine cross-linking in DNA, halting replication
****inability to repair UV damage
what (4) disorders are associated with characterized by hypersensitivity to DNA damage (AKA "fragile DNA" diseases)
familial breast cancers (BRCA1 & 2)