Neoplasia 1 + 2 Flashcards
(40 cards)
what is meant by the term neoplasm?
an abnormal growth of cells that persists after the initial stimulus is removed
what is oncology?
the study of tumours and neoplasms
what are the differnt types of neoplastic tumours?
- Benign
- Malignant:
* primary site (from where it originates)
* secondary (to where it has spread)
what is a benign neoplasm?
when gross and microscopic appearances are innocent
wont spread
what is a malignant neoplasm?
abnormal growth of cells that persist after initial stimulus is removed
invades sorrounding tissue + potential to spread to distant sites
what is meant by the term cancer?
malignant neoplasm
what is meant by the term metastisis?
malignant neoplasms have the ability to spread from primary site to a secondary site
what is dysplasia?
- pre-neoplastic alteration in cells
- reversible
- have large hyperchromatic nuclei
- high nuclear to cytoplasmic ratio
what are the main differences between benigns vs malignant neoplasm?
Benign:
* benign neoplasms remain confined to site of origin
* usually harmless (but dependent on location)
* pushing outer margin + grow within a capsule
* resembles the parent tissue - well differntiated
Malignant:
* malignant neoplasms have the potential to metastasise + infiltrate other tissues
* have an irregular outer margin
* may have ulcerations and necrosis
* how much it resembles parent tissue depends on how well it differentiates
what are malignant neoplasm cells which dont resemble parent tissue called?
anaplastic
what is meant by the term differntiation and what are the different types ?
process of becoming different by growth or development
benign neoplasms are well differentiated - uniform cells
malignant neoplasms can vary from well differentiated to poorly differentiated - fewer uniform cells
clinicians use grade as a synonym for differntiation:
1. grade 1 = well differentiated
2. grade 2 = moderately differntiated
3. grade 3 = poorly differentiated
what are the classic features of poorly differntiated malignant neoplasms?
- increasing nuclear size
- increasing nuclear : cytoplasm
- increased nuclear staining
- increased num of mitotic figures
- abnormal mitotic figures (mercedes benz symbol)
- variation in size and shape of cells and nuclei
what is the difference between dysplasia and neoplasm?
dysplasia refers to any changes within epithelial layer
once basement membrane is infiltrated then it is a malignant neoplasm
what are the different stages of dysplasia?
no.1 Dysplasia: reversible
* increased nuclear size
* loss of maturation towards surface of epithelia
* loss of keratin
no.2 Carcinoma in situ: irreversible
* full thickness dysplasia - all epithelia affected
* hasnt infilitrated basement membrane
no.3 Invasive carcinoma: irreversible
* infiltrates basement membrane
* malignant tumour
what is the CIN scale?
scale used to show how poorly differentiated epithelial surface is in cervix:
* CIN 1 = only the lower 1/3 of epithelia is showing classical features of poor differentiation
* CIN 2 = lower 2/3 of epithelial is showing classical features of poor differentiation
* CIN 3 = entire epithelia is showing classical features of poor differentiation
why do we get neoplasia?
- carcinogenesis
- non-lethal genetic damage
- accumulated mutations in somatic cells
- mutations are caused by initiators - mutagenic agents
- promoters that cause cell proliferation
- tumour forms by clonal expansion of a single precursor cell that has incurred genetic damage
what are the different initiators?
Chemicals:
* smoking
* alcohol
Infections agents:
* HPV
Radiation
Inherited disorders
what happens in the process of “progression”?
- start of with one cell which has a mutation
- this cell divides forming new monoclonal cells with the same mutation (if all cells originate from one single cell they are known as monoclonal)
- as time progresses these cells pick up new mutations which make them better adapted to survive
which genes are affected in neoplasms?
- growth promoting proto-oncogenes
- growth inhibiting tumour supressor genes
- genes that regulate programmed cell death (apoptosis)
- genes involved in DNA repair
to cause a neoplasm you likely need more than one affected gene
what are the impacts of mutations in proto-oncogenes?
- growth promoting genes - cause cell proliferation
- mutations can affect the normal function of these genes or give them a new function - this is known as a “gain of function” mutation
- mutations can permanently turn these proto-oncogenes on so it results in uncontrolled growth
- only need 1 allele to be affected
what are the impacts of mutations in tumour supressor genes (TSG)?
- normal function is to stop cell proliferation
- mutations cause loss of function
- cells continue to grow and no longer undergo apoptosis
- most common mutation occurs in the TB 53 gene
what are the impacts of mutations in apoptosis regulating genes?
abnormalities in apoptosis so cells dont undergo apoptosis and enhanced survival of cells
what are the impacts of mutations in DNA repair genes?
- loss of function mutations
- genetic damage to cells isnt detected so cant be repaired
- affected cells acquire mutations at an accelerated rate - this is AKA “state of mutator phenotype”
how can you name benign neoplasms?
benign tumours generally end in -oma
