Topic 10: Cancer 1 Flashcards
what are major features that define cancer
cells that have uncontrollable proliferation and are able to invade and colonize other tissue
how can uncontrollable proliferation occur?
it happens when the balance of cell division and apoptosis is off rather
- increased cell division with normal apoptosis
- decreased apoptosis with normal cell division
- increased in both cell division and apoptosis
definition of oncogenesis
the microevoultionary process that usually takes years r decades for cancer to form and is generally an accumulation of mutations
what is a begin tumour?
is when cell profileration occurs but the cells stay in its appropriate tissue
- the size of the mass may cause issue which leads to removals
what is a malignant tumour?
it is when the proliferated cells leave their appropriate tissue and evade other sections by traveling through the bloodstream
what are all the hallmarks of cancer? (8) (tumourgenosis)
- self sufficient growth signals
- insensitivity to antigrowth signals
- apoptosis inability
- unlimited replication potential
- tissue invasion (metastasis)
- sustained angiogenesis
- alluding immune destruction
- increased mutation rate
carcinoma
cancer in the epithelial cell
sarcoma
cancer in the connective or muscle tissue
leukemia/lymhoma
cancer on the hematopoietic stem cells
adenoma
type of carcinoma; benign epithelial tumour in a duct of a gland
chondroma
benign tumour of cartilage
how can tumorigenesis start?
by a single mutation in a chromosome that slowly builds up with multiple mutations
- philadelphia chromosome: a translation in chronic myelogenous leukemia
other mutation can be
- deletion
- translocaion
- addtion
- point muation
what is the most common cancer of old age?
colon cancer
describe the process of the multi-hit model
(what leads to metastasis) basically an acclimation of undetected mutations
- a single mutation occurs and is not fixed then its descendants get mutated as well causing more profiltation and those descendants divide uncontrollably as well then tumour is growing
how do benign grow?
(carinoma example)
- a polyp forms on the wall of organ
- a benign cancerous tumor starts to grow
- class 2 (adenoma) benign
- class 3 (adenoma) benign
- malignant carcinoma
what SPECIFIC of mutations cause cancer to grow?
- loss of APC tumor suppressor
- loss of K-ras oncogene
- loss of tumor supressor gene in region of chomosome 18q
- loss of p53 (tumour supressor)
describe the process of metastasis
after growing in its section of tissue for awhile
- it loses its adherens & desomomes (cell-cell adhesion)
- penetrates through the basel lamina ( hemidesmosomes and actin linked cell matrixes break)
- intravasation: enters the blood vessel
- extravasation: exits the bloodstream into another tissue
- proliferates in the new tissue
what do tumours do to survive in their mircoenvironment
- have altered sugar metabolism
- induce angiogenesis
explain the altered sugar metabolism of cancer cells
they have a very high glucose uptake and they need to produce building blocks from glycolysisis. The increased glycolysis causes an increase in lactate which they use for energy
what is angiogenesis
the extension of a capillary to the cancer site to fuel it
it occurs do the secretion of these growth factors
- basic FGF
- transforming growth factor alpha (TGF alpha)
- vascular endothelial growth factor (VEGF)
explain how tumour cells VEGF expression
since the O2 levels are down in the cancer cells, they release hypoxia inducible factor occurs (HIF). This stimulates the production of VEGF so the a capillary network can grow towards it.
what is replicative senescence (not die)
the cell division mechanism that counts how many times the cell has replicated and alerts it to stop dividing when telomere is too short
how do they avoid replicative senescence
all somatic cells stop dividing when their telomere gets too short however, cancer cells can escape the built in limit of cell proliferation
- they maintain telomere expression (just like stem cells)
- they make another way based on homologous recombination for elongating their chromosome ends
what is the difference between normal and cancer cells in culture
normal cells
- grow flat
- have finite divisions
- require growth fators
- respond to inhibitory growth factors
maglinant cells do the opposite
