Neoplasia Flashcards
Tumour definition
Mass or swelling
Neoplasm
Abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues and persists in the same excessive manner after cessation of the stimuli which evoked the change
Define benign
Neoplasm which is localised and cannot spread
Define malignant
Neoplasm which can invade and destroy adjacent structures and spread to distant sites
Define cancer
Malignant neoplasm
Define metastasis
Spread of a cancer to a distant site
What is the normal cell turnover and healing and repair
The cells proliferate to replace damaged or apoptotic cells
And once the tissue has regained its normal structure proliferation ceases - no mutations have occurred
What is a clinically irrelevant mutation
By chance a cell may develop a mutation which does not confer a survival advantage
So proliferated but the irrelevant mutation does not dominate since they have no survival advantage over the normal cells
What happens in a benign neoplasia
A neoplasm is formed by the clinal expansion of a single precursor cell that has a survival advantage over its neighbours
In the pretumoural stageneoplastic mutations are present in the tissue, but have not yet given rise to a tumour. These are typically clinically silent
Over time the neoplastic clone dominates the tissue and forms a mass. Cells do not have malignant capacity so is a benign tumour
Where do benign tumour go
Nowhere they are limited to the site of origin, but show expansive growth and do not metastasise Often clinically irrelevant but Can cause Compression Obstruction Bleeding Hormone secretion Cosmetic effect Progression to malignancy
What is in situ neoplasia
Some mutations (arising either de novo or in benign neoplasm) give cells malignant capacity The malignant phenotype comes to dominate the tissue , but so far the cells have not actually invaded the basement membranes So is in situ malignancy
Where does in situ neoplasia go
Biologically has malignant potential , but has not yet invaded beyond the confines of the normal tissue e.g. Basement membrane
Can be considered pre cancerous
Complete excision is curative
Often asymptomatic as does not form a mass
Important for screening programmes
Cancer is
Cells with a malignant phenotype that invade local structures and spread through tissues
Invasive malignancy
What is cancer
Malignant neoplasm
Has the ability to invade and destroy
Capacity to invade and destroy adjacent tissues
Has the capacity to metastasise
Metastasis invade and destroy adjacent tissue
Hallmarks of cancer
Sustaining proliferative potential Evading growth suppressors Avoiding immune destruction Enabling replicative immortality Tumour promoting inflammation Activating invasion and metastasis Inducing angiogenesis Genome instability and mutation Resisting cell death Deregulating cellular energetics Sustaining proliferative signalling
