Flashcards in MOD 8 Deck (91):
What is a neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed.
What is a malignant neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed AND invades surrounding tissue with potential to spread to distant sites.
Define a tumour:
Any clinically detectable lump or swelling (cancer is just one type of tumour).
Any malignant neoplasm.
A malignant neoplasm that has spread from its original site (primary site) to a non-contiguous site (secondary site).
What is dysplasia?
A pre-neoplastic alteration in which the cells show disordered tissue organisation. It is not neoplastic because change is reversible.
How does the gross morphology of benign and malignant neoplasms differ?
Benign neoplasms grow in a confined area and so have a pushing outer margin (this is why they are so rarely dangerous). This results in them pushing and squashing surrounding tissue into a pseudocapsule of compressed tissue. Malignant tumours have an irregular outer margin and shape and may show areas of necrosis and ulceration (if on a surface). They are attached to the surrounding tissue and therefore are not mobile.
What are 'initiators' of neoplasms? Give some examples of 'initiators':
Mutagenic agents that cause mutations that lead to neoplasms e.g. chemicals, infections and radiation.
What are 'promoters' of neoplasms? Give some examples of 'promoters':
A substance, though not mutagenic itself, aids in neoplasm formation by causing cell proliferation. Though some substances act as both initiators and promoters.
What is the result of the action of initiators and promoters combined? How does this ultimately result in a neoplasm?
They produce an expanded monoclonal population of mutant cells. Neoplasms emerge from this population through a process called 'progression', characterised by the accumulation of yet more mutations.
Are mutagens the only cause of mutations that cause neoplasm?
No, some neoplasm mutations are caused by inherited rather than external mutagenic agents.
What does a monoclonal population of cells mean?
That that population of cells all originated from a single founding cell.
Describe some evidence that neoplasms consist of a monoclonal cell population.
In female embryogenesis, one of their X chromsomes is randomly inactivated in each cell (Lyonisation). On the X chromosome is a gene for G6PD which has various isoforms. In heterogenous woman with a heat stable and heat labile isoform of this gene, normal tissues will have a patchwork of each type of gene whereas neoplastic tissue only expresses one genotype.
Mutation of which types of genes leads to the formation of a neoplasm?
Proto-oncogenes (abnormal activation) and tumour suppresser genes (inactivation).
What are abnormally activated proto=oncogenes called?
What is the suffix that tends to be used for benign neoplasms?
What is the suffix that tends to be used for malignant neoplasms?
1. -carcinoma (if it is an epithelial malignant neoplasm)
2. -sarcoma (if it is a stomal malignant neoplasm)
How many malignant tumours are carcinomas?
What is the difference between in-situ and invasive carcinomas?
In-situ carcinomas have not invaded through the epithelial basement membrane whereas invasive have.
What is leukaemia?
A malignant neoplasm of blood-forming cells arising in the bone marrow.
What are lymphomas?
Malignant neoplasms of lymphocytes that mainly affect lymph nodes.
What is myeloma?
A malignant neoplasm of plasma cells.
What type of cell do germ cell neoplasms arise from? Where are they mainly found?
From pluripotent cells, mainly in the testis or ovary.
Where do neuroendocrine tumours arise from?
Cells distributed throughout the body.
What does the suffix -blastoma mean?
It is used to describe neoplasms which mainly occur in children and are formed from immature precursor cells e.g. nephroblastoma.
What is the difference between hyperplasia and neoplasia?
They both can consist of an abnormal growth of cells, however neoplasia PERSISTS after the initial stimulus is removed, whereas hyperplasia is reversible.
Give some examples of non-neoplastic tumours:
What behvioural changes can be seen with a frontal brain tumour?
Heightened sexualised behaviour.
Cells with no resemblance to any tissue. There has been loss of differentiation of these cells and their orientation to each other.
What variation in degrees of differentiation of cells in benign neoplasms can be seen under the microscope?
They are well differentiated and therefore closely resemble their parent tissue.
What variation in degrees of differentiation of cells in malignant neoplasms can be seen under the microscope?
They vary from well differentiated to poorly differentiated to anaplastic.
What is hyperchromasia?
Increased nuclear staining of cells.
What is pleomorphism?
Increasing variation in size and shape of cells and nuclei.
What features of cells in a neoplasm correlate with reduced differentiation?
1. Increased nuclear size
2. Increased nuclear to cytoplasmic ratio
3. Increased nucleus staining (hyperchromasia)
4. More mitotic figures
5. Increasing variation in size and shape of cells and nuclei (pleomorphism)
What does a low grade neoplasm mean? What does a high grade neoplasm mean?
Low grade it well differentiated and high grade is poorly differentiated cells in a neoplasm.
What is the association between grade of neoplasm and breast cancer 5 year survival?
As the grade of neoplasm increases (neoplastic cells show decreasing differentiation) the prognosis/ chance of 5 year survival becomes worse.
When does dysplasia become neoplasia? How can you tell down the microscope?
It is not possible to distinguish the borderline between dysplasia and carcinoma down the microscope, but it is easy to detect when a carcinoma becomes invasive and penetrates the basement membrane.
What features are used to track the progression of worsening differentiation of epidermis from normal -> dysplasia -> carcinoma in-situ -> invasive carcinoma?
Loss of keratin is seen as reduction of specialisation (differentiation) of cells occurs. Invasion is seen by penetration through the basement membrane. Invasive carinomas show tripolar mitosis (produces three daughter cells).
How much cancer risk is associated with environmental/ extrinsic factors?
What characteristics of an initiator also make it a promoter?
If it causes cell damage it will also cause proliferation.
Why do families with germline mutations of proto-oncogenes or tumour supressor genes often develop neoplasm earlier than non-inherited forms?
The neoplastic cells get a "head start" as all cells in the body already have one mutation that increases the risk of neoplasm development.
What types of cellular pathways do proto-oncogenes and tumour supressor genes work on?
Any pathway involved in growth e.g. angiogenesis.
What is the difference in dominance of mutations that affect proto-oncogenes versus tumour supressor genes?
Only one proto-oncogene need to be switched on inside for it to have an effect (therefore mutations are dominant). Wherease both genes of tumour supressor genes would need to be inactivated by mutations.
What is a squamous papilloma? Where does it occur?
Any stratified squamous benign epithelial tumour with finger-like projections. These can occur on skin or buccal mucose.
What is transitional cell papilloma? Where does it occur?
A benign transitional epithelial tumour which protrudes from the surface. They can occur in bladder mucosa.
What is an adenoma?
Benign tumour formed from glandular epithelia.
Where do stratified squamous carcinomas occur?
Skin, larynx, oesophagus, lungs, others.
Where do transitional cell carinomas occur?
Bladder and ureters.
Where do adenocarcinomas occur?
Stomach, colon, lung, prostate, breast, pancreas, oesophagus and others.
Where does basal cell carinoma occur?
What is a leiomyoma?
Benign smooth muscle (connective tissue) benign neoplasm.
What is a fibroma?
A fibrous tissue benign neoplasm.
What is an osteoma?
A bone benign neoplasm.
What is a chondroma?
A cartilage benign neoplasm.
What is a lipoma?
A fat benign neoplasm.
What is a neuroma?
A nerve benign neoplasm.
What is a neurofibroma?
A nerve sheath benign neoplasm.
What is a glioma?
A glial cell benign neoplasm.
What is a leiomyosarcoma?
A malignant smooth muscle cell neoplasm.
What is a osteosarcoma?
A malignant bone neoplasm.
What is a fibrosarcoma?
A malignant fibrous tissue neoplasm.
What is a chondrosarcoma?
A malignant cartilage neoplasm.
What is a liposarcoma?
A malignant fat neoplasm.
What is a malignant glioma?
A malignant glial cell neoplasm.
What do lymphoid and haematopoetic neoplasms have in common?
They are all regarded as malignant.
Name two germ cell neoplasms that can occur in testis:
Malignant teratoma and seminoma (malignant).
What is the difference between malignant teratoma and siminoma (malignant) of the testis?
Teratomas differentiate into lots of different tissues whereas seminomas remain like germ cells.
What teratoma can occur in the ovaries? Is it benign or malignant?
Dermoid cyst (skin, hair etc... inside) = benign teratoma.
List some neuroendocrine tumours. Where do they occur?
1. Carcinoid tumours (various organs)
2. Phaeochromocytoma (adrenal -Chromafin cells)
3. Small cell carinoma of bronchus.
The study and treatment of tumours.
A colony of cells derived from a single progenitor cell by mitosis. Therefore they all have identical DNA.
Hard and fibrous, especially of certain malignant neoplasms which contain dense fibrous tissue.
What is a cystadenoma?
A cystic adenoma: benign tumour of epithelial tissue with glandular origin which creates a liquid-filled cavity.
What is a polyp?
An abnormal growth of tissue projecting from a mucous membrane.
What is a rhabdomyosarcoma?
A sarcoma that is believed to have skeletal muscle origin.
What is a haemangioma?
Benign tumour of blood vessels.
What is an angiosarcoma?
A malignant neoplasm of endothelial-type cells that line vessel walls (blood or lymph vessels).
What is a mesothelioma? What is the most common cause of it?
Neoplasm of mesothelial lining of body cavities, most commonly the lungs (almost always malignant). More than 80% of it is caused by exposure to asbestos.
What is rhabdomyoma?
A benign tumour of striated muscle (skeletal or cardiac).
What is basal cell carcinoma?
A type of malignant skin cancer of the basal cells of the epidermis.
What is hepatocellular carcinoma?
The most common type of liver cancer. It is malignant and mainly caused by viruses (hepatitis B,C) or cirrhosis (alcohol-related the main cause).
What is a naevus?
A mole: benign melanocyte neoplasm.
What is malignant melanoma?
A malignant neoplasm of melanocytes that is typically in the skin but can also occur in the eyes, mouth and intestines.
What is hamartoma?
A benign focal malformation that resembles a neoplasm in the tissue of its origin. This is not a malignant tumor, and it grows at the same rate as the surrounding tissues. It is composed of tissue elements normally found at that site, but which are growing in a disorganized mass. They occur in many different parts of the body and are most often asymptomatic and undetected.
What is the difference between a benign neoplasm and a hamartoma?
It is unclear, since both lesion can be monoclonal.
Differentiation is a process that determines which genes are expressed in a cell and hence the specialisations of a cell so that it can perform a specific function.
What is a choriocarcinoma?
It is a malignant trophoblastic neoplasm, usually of the placenta, but can arise in testis or ovaries too. It is characterised by early haematogenous spread to the lungs.
What is a teratoma?
A teratoma is a tumor with tissue or organ components resembling normal derivatives of more than one germ layer. Although the teratoma may be monodermal or polydermal (originating from one or more germ layers), its cells may differentiate in ways suggesting other germ layers.
What is astrocytoma?
These are mainly malignant neoplasms of astrocytes and therefore are a type of glioma.
What is papilloma?
A benign epithelial tumour that grows outwards in nipple-like and often finger-like projections.