Normal Vs cancer tissue Flashcards
In which cell type do most cancers arise? Why?
Epithelia - Rapidly proliferating, interface between body and the environment. (Take all mutagenic hits)
Which form of cancer is most rare?
Sarcomas - Normal stromal tissue (Muscle, fat etc) which don’t proliferate much after childhood.
What is Metaplasia?
The transformation of one cell type into another
What normally causes metaplasia
Chronic inflammation/ irritation
What does metaplasia increase the risk of>
Dysplasia and carcinoma formation.
Is metaplasia due to epigenetic or genetic changes
Potentially either.
What causes gastric metaplasia?
Excess acid in the proximal duodenum. Gastric metaplasia causes the transformation of duodenal epithelia to gastric epithelia, which are better at dealing with acid conditions.
What type of epithelium are present in a normal oesophagus
Squamous epithelium for strength
What can cause Barrett’s Oesophagus
Overweight, old, smokers may begin to get reflux of stomach acid and bile into the oesophagus. Long term effect of this is to turn squamous epithelium into glandular epithelium which is better at dealing with acids and bile.
What is dysplasia
cells are abnormal in form, usually meaning they are pre-malignant (in adults, not children)
What cellular features are identified in dysplasia?
Increase in nuclear/cytoplasmic ratio
Nuclear pleomorphism (Variation in its size and shape)
Nuclear hyperchromatism
Increased numbers and abnormal mitotic figures.
What are some architectural features of dysplasia
Loss of nuclear polarity
Failure of cellular maturation
Tissue disorganisation
- Irregular glands
- Back to back glands
- Villiform change
How do each stage of cervical intraepithelial neoplasia differ?
Normal - Clear purple base layer, where the stem cells can be found. As they mature and differentiate they move up toward the lumen. Some epithelium develop some glycogen causing white holes histologically.
CIN1 - Lower third shows expansion of the basal cells and a little atypia
CIN2 - Big chunky cells halfway up the epithelium
CIN3 - No maturation of epithelia, all of the cells are highly atypical.
When does a tumour become malignant?
Only once it has become invasive. Dysplasia is therefore considered benign even though it likely has a very similar mutational profile to the eventual neoplasm.
What is meant by benign
Encompasses all neoplasia that is yet to invade beyond the basement membrane or metastesised.
