MoD 8 Neoplasm I Flashcards
Define the term ‘dysplasia’
A reversible change in which the tissue becomes disorganised. This is a pre-neoplastic change. It is not neoplastic itself but it can become neoplastic.
Define the term ‘tumour’
A clinically detectable mass or swelling.
A neoplasm is a type of tumour.
Define the term ‘Cancer’
A malignant neoplasm.
Define the term ‘metastasis’
A malignant neoplasm that has spread to a non-contiguous secondary site. The site from which it spread from is the primary site.
Define the term ‘anaplasia’
Cells which have no resemblance to any tissues. These are called anaplastic.
Define the term ‘pleomorphism’
These are cells in which their size and shape is variable and there is increased mitotic figures present.
Describe the differences in the macroscopic features of benign and malignant neoplasms.
Benign neoplasms grow in a confined area and so they have a ‘pushing’ outer boundary. This is why they are rarely dangerous.
Malignant neoplasms have an irregular outer margin that may show signs of ulceration if on a surface.
Benign neoplasms remain at their site of origin.
Malignant neoplasms remain after the stimulus has been removed and invade local tissue, with the potential to metastasise.
Describe the microscopic features of malignant and benign neoplasms.
The appearance under the microscope is the basis for grading tumours.
Benign tumours that resemble the parent tissue are called well differentiated.
Malignant neoplasms can be well differentiated to poorly differentiated. A poorly differentiated neoplasm is almost never benign.
Remember that cells that don’t resemble any tissue are termed anaplastic.
How are tumours graded?
Based on their differentiation. The poorer the differentiation, the worse the tumour is.
Eg a high grade tumour is poorly differentiated.
A low grade tumour is well differentiated but could still be malignant.
Describe the changes seen with worsening differentiation.
Increased nuclear:cytoplasmic size ratio
Increased mitotic figures.
Increased nuclear staining - HYPERCHROMASIA.
Increased variation in size and shape of the nucleus- PLEOMORPHISM
These changes correlate to the level of differentiation. The poorer the differentiation, the more of the above changes will be seen.
In terms of 5 year survival, what is the change seen with a grade 3 breast cancer compared to that of a grade 1 Cancer.
G3- 50% 5 year survival
G1- 90% 5 year survival.
What factors are responsible for mutations and what factors are responsible for proliferation of cells ?
Initiators cause mutations
Promotors cause cell proliferation.
What is senescence?
This is the process of putting a cell into G0 forever.
Senescence and apoptosis (p53) prevent DNA mutations from occurring on a daily basis. ~85% of cancers are caused by extrinsic factors.
Through what process do neoplasms emerge from the monoclonal population?
Progression.
Which types of genes are involved in neoplasia?
Abnormal activation of proto oncogenes. These code for growth factors. Once abnormally activated, they are known as oncogenes. These oncogenes favour neoplasia.
Tumour suppressor genes inhibit neoplasm formation. These must become suppressed.
