tumour biology Flashcards
differentiation invloves…
- the inactivation of proliferation genes
- the activation of specific function genes
de-differentiation involves…
reversion to primitive, embryonic and proliferative phenotypes as occurs in neoplasia
(involved in cancer)
disorders of growth refers to…
the regulation of proliferation or differentiation
agenesis
the total absence of structure or organ
hypoplasia
congenital reduction in size
atrophy
acquired reduction in size
hyperplasia
increased number of cells
hypertrophy
- can refer to both cells or whole organs
- is an increase in size
premalignant
a statistical concept relating to an increased probability of developing into cancer
causes of hyperplasia
- chronic irritant e.g. ulcer
- endocrine stimulation
- “functional” physiological
effects of hyperplasia
increased function
risk of malignancy (for some types)
metaplasia
change from one mature tissue type to another
- some are premalignant
- caused by change in environment or irritation
dysplasia
- only seen under the microscope (histological abnormality)
- all are premalignant
- is the partial malignant transformation
- various grades
- cells are clonal
opportunity to remove tissues, prevent invasive cancer
neoplasia
new growth
another name for dysplasia
intraepithelial neoplasia
reactive atypia
after injury cells carry out regeneration and proliferate. As a result of increased rates of turnover, cells are at risk of genetic abnormalities and cells can look like dysplasia
the difference between benign and malignant neoplasms
benign:
- do not metastasize
- cells are differentiated
- expansile growth
- rarely fatal
malignant
- most types metastasize
- cells less differentiated
- infiltrative growth, rapid
- fatal if untreated
components of solid tumours seen under microscope
- new blood vessels forming
- immune response
- production of fibrosis tissue
tumour stroma
everyting in the tumour apart from the cells
- fibroblast, collagen, matrix
- new blood vessels
- inflammatory cells
tumour cell hypoxia
uncoordinated growth of cells causes new vessels to form uncontrollably. As a result not all cells are insufficiently supplied with oxygen causing necrotic tissue to occur
- illustrated high grade tumour if large number of necrotic tissue
- hypoxic cells are resistant to radiation
what is the pathological diagnosis when you know a cell is malignanat
- stage
- grade
- type
microscopic diagnosis of malignancy
- architecture
e. g. disorganised, invasion of normal tissue - cell features
e. g. increased nuclear size, variation in shape, mitoses, decreased cell cohesion
how does stroma cells prevent growth of tumours
- apoptosis
- DNA repair damage
- immunosurveillance
anaplasia
lack of differentiation
define heterogeneity
the difference in cell genes
- consequently means resistance can occur
how could mutations in DNA mismatch repair genes promote the formation of tumours
as DNA is being replicated DNA repair genes are being cycled to detect any errors intoduced. However a mutation in DNA mismatch repair genes means there is greater risk for cells to acquire mutations causing cancer
how do cancer cells avoid immune effectors
- decrease in HLA class 1 expression
- resistance to immune attack
- release immune inhibitors
- amino acid depletion (deplete environment)
- activate inhibitory T cells
- poor immunogenicity
