Neoplasia 1 Flashcards
Define a Tumour
Define a Neoplasm
Define Cancer
Define a Metastasis
Tumour: A clinically detectable lump or swelling
Neoplasm: An abnormal growth of cells that persists after the initial stimulus is removed
Cancer: A malignant neoplasm
Metastasis: A malignant neoplasm that has spread from its original site to a new non-contiguous site
Compare Primary and Secondary Sites of a malignant neoplasm
Primary site: Original location of the malignant neoplasm
Secondary site: Place to which a malignant neoplasm has spread (Metastasis)
Compare the Behaviour of a Benin and Malignant Neoplasm
Benign Neoplasms:
- Remain confined to their site of origin and do not produce metastases
Malignant Neoplasms:
- Invade distant sites and can metastasise
Compare the Apperance to the Naked Eyes (Macroscopic features) of Benign and Malignant Neoplasms
Benign Neoplasm;
- Grow in a confined local area
- Have a pushing outer margin
- Rarely dangerous (due to location)
Malignant Neoplasm;
- Irregular outer margin and shape
- May have ulcerations and necrosis
- Infiltrative
Compare the Microscopic appearances of Benign and Malignant neoplasms
What are Anaplastic cells
Benign:
- Closely resemble the parent tissue( are well differentiated)
Malignant:
- Range from well to poorly differentiated
Cells with no resemblance to any tissue
How do the following change with worsening differentiation;
- Nuclear size
- Nuclear to cytoplasmic size
- Nuclear staining
- Mitotic figures (Lacking a nuclear membrane, hairy projections of chromosomes)
- Size and shape of cells and nuclei
- Increase
- Increase
- Increase (Hyperchromasia)
- More + Abnormal
- Increased variation (Pleomorphism)
What term do clinicians use to indicate differentiation of a tumour
What does Mild, Moderate and Severe dysplasia indicate
Grade (High grade= poorly differentiated)
Indicates worsening differentiation
Compare Invasive and In-Situ malignancy
Invasive: Breach of basement membrane
In-situ: Basement membrane not breached
What causes Neoplasia
What 2 things cause these? What do they do?
Accumulated mutations in somatic cells
Initiators: Cause mutations
Promotors: Cause cell proliferation
What is the result of a combination of Initiators and Promotors
By what process does this lead to a Neoplasm forming?
What characterises this process?
An expanded monoclonal population of mutant cells
Progression, characterised by accumulation of more mutations
Name the 3 main initiators/ promoters that cause a neoplasm
What is another way cells can be mutated
- Chemicals (Smoking/ Alcohol/ Diet and Obesity)
- Infections (HPV)
- Radiation
- Inherited mutations
What 4 types of genes are affected by genetic alterations, leading to mutations.
- Proto-oncogenes (Growth promoting)
- Tumour suppressor genes (Growth inhibiting)
- Genes that regulate apoptosis
- Genes involved in DNA repair
How do mutations generally affect proto-oncogenes to activate them?
How do Oncogenes cause growth of the cell
Are oncogenes dominant over (normal) proto-oncogenes
Generally cause in excessive increase in 1/ more normal functions (Gain of function mutations)
Produce Oncoproteins that can promote cell growth in the absence of normal growth promoting signals
Yes
How do mutations affect Tumour Suppressor genes to lead to cancer?
How do mutations generally Apoptosis Regulating genes to cause cancer?
Loss of function mutations, leading to failure of growth inhibition
Apoptosis regulating genes may acquire abnormalities that result in less cell death, and enhanced cell survival
How do mutations affect DNA Repair genes to lead to cancer in 2 ways?
(Loss of function mutations)
- Impair the ability of the cell to recognise and repair non-lethal genetic damage in other genes
- Leads to cells acquiring mutations at an accelerated rate (Mutator Phenotype, marked by genomic instability)
