MoD Session 8 Flashcards
What does cell growth become in neoplasm?
Autonomous
What is neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed
How is neoplasm distinguished from inflammation clinically?
Neoplasm is cold to touch
When would neoplasm not cause a lump?
In leukaemia
What is malignant neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed and which invades surrounding tissue w/potential to spread to distant sites
What must be present in cells to cause neoplasia?
Genetic alterations
What is a tumour?
Any clinically detectable lump or swelling
What two types of tumour can form?
Non-neoplastic
Neoplastic
What two types of neoplastic tumour are there?
Benign
Malignant
What is metastasis?
Malignant neoplasm that has spread from its original location to a new non-contiguous site
Why might removal of a primary malignant neoplasm not prevent spread of cancer?
Each secondary tumour has the potential to spread
Is tumour formation reversible?
Nope
What is dysplasia?
Pre-neoplastic alteration in which cells show disordered tissue organisation
Is dysplasia reversible?
Yes
How are benign neoplasms characterised?
Remain confined to site of origin
Do not produce metastases
Create a pseudocapsule
What does the danger of a benign neoplasm depend on?
What tissue it is pressing on
What characteristics do malignant neoplasms display?
Irregular outer margin and shape
Can show ulceration in centre due to inadequate blood supply formation
Have the potential to metastasise
What do the cells of a benign neoplasm closely resemble?
Parent tissue
How can the cells in a malignant neoplasm vary?
From well to poorly differentiated
What term is used to describe cells with no resemblance to any tissue?
Anaplastic
What examines tissue cells ex situ so there is no architecture surrounding them?
Cytology
How do poorly differentiated cells compare to sell differentiated cells?
Increased: Nuclear size Nucleus:cytoplasm ratio Pleomorphism Hyperchromasia Mitotic figures
What is pleomorphism?
Variance in cell and nuclei size and shape
How may mitotic figures appear in poorly differentiated cells?
May be abnormal
How is the grading of neoplasm determined?
Grade 1-3 with decreased differentiation with each stage
What happens to mortality with each increase in neoplasm grade?
It increases by 40%
What indicates worsening differentiation?
Mild –> moderate –> severe dysplasia
At what point does dysplasia become neoplasia?
When the worsening differentiation becomes irreversible
How long can the development of dysplasia into neoplasia take?
Years
What three aspects does the Modified Bloom Richardson grading for breast cancer examine?
Tubules
Mitoses
Nuclear pleomorphism
What percentage of cancer risk is extrinsic?
~85%
What change is seen in skin which has undergone reversible dysplasia?
Decreased specialisation causing loss of keratin
What change is seen in skin which has undergone irreversible dysplasia?
Tripolar mitosis
Invasive carcinoma
What causes neoplasia?
Accumulated mutations in somatic cells
How are the 10 million opportunities for somatic cell mutation per second dealt with to prevent neoplasia?
Apoptosis
Cell senescence
What causes a cell to enter G0?
Oncogene
What two things are needed to cause neoplasia?
Initiators
Consistent promoters
What are the main initiatiors of neoplasm which can also act as promoters?
Chemicals
Infection
Radiation
What causes early onset of cancer by skipping the initiator/promoter step of neoplasm?
Inheritance of a germline mutation
What is progression?
Formation of a neoplasm by accumulating more mutations by subclonal expansion
What causes heterogenous cells to be present within a neoplasm?
Progression
Is a neoplasm formed from progression monoclonal?
Yes, from same founding cells
What is a monoclonal tumour?
Tumour which originates from a single founding cell
What can be studied to identify monoclonal tumours?
X-linked G6PD
How are different alleles of G6PD gene switched off during female embryogenesis?
Randomly by lyonisation
What expression of G6PD izoenzyme is seen in normal tissue?
Patchwork of cells expressing both heat stable and heat labile isoenzymes
What isoenzyme expression of G6PD is seen in neoplastic tissue?
Either only maternal or paternal isoenzyme expressed
What genetic alteration occurs in proto-oncogenes which favours neoplasm formation?
Abnormally activated oncogenes
Why does abnormal activation of a proto-oncogene only need activation of one allele?
It is positively acting
What is the effect of abnormal activation of proto-oncogenes?
Abnormally pushes cell through cell cycle
What happens to tumour suppressor genes to favour neoplasm formation?
Inactivation of growth factor
Cyclin inactivators
Inactivation of receptors
Why is deletion of both alleles of tumour suppressor genes needed to cause neoplasia formation?
Alleles have an inhibitory function
What words with the suffix -oma are not neoplasms?
Granuloma
Atheroma
Haematoma
What suffix do neoplastic blood disorders have?
-aemia
What are the two types of benign epithelial tumour?
Papilloma
Adenoma
What are papillomas?
Benign non-glandular/non-secretory epithelial tumours