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23 terms

Metastasis

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Checklist for metastasis
1) generates own growth signals
2) insensitive to antigrowth signals (loss of Rb, p21, p16)
3) able to evade apoptosis
4) immortalization
5) sustained angiogenesis
6) ability to invade basement membrane
E cadherin inactivation
loosens site of attachment; aids in metastasis
Protease expression
cuts through basement membrane
Metastasis
when tumor cells leave their organs of origin and spread elsewhere
Invasion
capability to transgress epithelial basement membrane; lesion now considered cancer; invasion does not equal metastasis
Size for angiogenesis
2mm beyond their site of origin - need O2 and nutrients
Ways for neovascularization
1) tumor cells, macrophages, stromal cells
2) production of NF-kB
Neoplastic vessels
1) disorganized
2) bleed easily, even without trauma
3) dilated and highly permeable
4) premature lack of mural cells
5) sluggish blood flow
Carcinoma-associated fibroblasts (CAF)
help to degrade basement membrane and interstitial tissues
How to get through basement membrane
1) loosen up cell junction
2) degrade BM and interstitial tissues
3) expression of receptors for stromal elements
4) get the cells moving
Stromal fibroblasts
aid in carcinogenesis; promote desmoplasia
Desmoplasia
dense fibrosis of stroma of a tumor; so much so that FNA cannot be performed
Tumor Spread Methods
1) direct invasion into adjacent tissue
2) invade lymphatics
3) seeding of body cavities
4) intravascular dissemination (hematogenous)
Seed and soil hypothesis
means tumor has metastasize and a tissue has to the right receptors/conditions/fertile ground for the tumor cells to take up residence
Benign neoplasm characteristics
1) usually well-circumscribed
2) push, don't infiltrate
3) may have capsule/pseudocapsule
4) respect borders
5) sometime hang out (leiomyoma)
Intraepithelial neoplasia
transformed epithelium with some cytologic features of malignancy but lacking the biological ability to invade and metastasize
Hypervascular neoplasms
1) hepatocellular carcinoma
2) renal cell carcinoma
3) carcinoid tumors
4) paragangliomas
Basal cell carcinoma of skin
Invades locally and can destroy large parts of the area it evolves in if it isn't treated, but rarely metastasizes
Papillary carcinoma of the thyroid
cancer tends to do nothing or spread locally to the nodes of the neck. one of the more benign cancers
Ductal carcinoma of the breast
highly aggressive
Renal cell carcinoma
usually invades renal veins
Hepatocellular carcinoma
invades portal and hepatic veins
Hematogenous spread
typically appear circumscribed as apposed to the appearance of the primary malignancy; can be a number of metastases in the same area (lung slide); look at cell type to confirm it is from another organ