Neoplasia Flashcards
What is neoplasia?
Abnormal growth of uncoordinated tissue mass.
Once the stimulus is removed the mass keeps growing.
Can be benign and malignant.
Describe the growth of a benign tumour?
Slow.
The whole mass grows at the same rate.
Under the microscope, how do benign masses appear?
Similar to the tissue of origin.
Why do benign tumours not invade surrounding tissues?
Have a connective tissue capsule.
Both benign and malignant tumours of the endocrine glands are life-threatening; why is this?
Can release hormones in excessive amounts/when not necessary.
What is metastasis?
The malignant tumour can travel around the body and invade distant tissues.
What does a malignant tumour look like under the microscope?
Can look like the tissue of origin or be totally unrecognisable.
Pleomorphism: cell size varies and so too does the size of the nucleus.
Name both a benign and malignant tumour of the salivary gland.
Benign: Pleomorphic adenoma.
Malignant: Squamous cell carcinoma.
What is a sarcoma?
Malignancy of the connective tissue.
What is a carcinoma?
Malignancy of the epithelial tissue.
What causes carcinogenesis?
Chemical agents.
Physical agents.
Oncotic viruses.
Name the 3 stages of carcinogenesis.
Initiation: Permanent DNA damaged by mutations.
Promotion: Mutating agent acts of the initiated cell.
REVERSIBLE UP UNTIL THIS POINT.
Progression: Passenger mutations occur along the way. IRREVERSIBLE.
What cells are most effected by ionising radiation (physical carcinogenesis)?
Labile cells.
The human papilloma virus is an example of an oncotic virus; what types cause cervical and oropharyngeal carcinomas?
HPV 16 and 18
Name an example of a potentially malignant disorder?
Leukoplakia: White lesion.
What histological appearance means the cell has the potential to become malignant?
Dysplasia.
Name the 4 genes that are important in carcinogenesis.
Oncogenes.
Tumour suppressor genes.
DNA repair genes.
MicroRNA.
What are porto-oncogenes? What are they called when they start to mutate?
Genes that regulate cell division.
Once they start to mutate they’re called oncogenes.
How many mutations do oncogenes require before they become malignant?
1
What are tumour suppressor genes?
Inhibits cell division and suppresses growth.
What is the hypothesis associated with tumour suppressor genes?
Knudson’s two hit hypothesis: 2 genes must mutate before the cell becomes malignant.
Name an example of a gene that applies to the Kudson’s hypothesis.
Retinoblastoma gene.
What can p53 be inactivated by?
Oncotic viruses.
This means there is no repair/apoptosis of damaged cells.
What are the 6 hallmarks of cancer?
Be able to produce its own growth factors.
Be insensitive to anti-growth signals.
Have the ability to metastasise.
Have a long life.
Have a supply of blood vessels.
Be able to evade apoptosis.
