T5: Characteristics of Tumours Flashcards
Define tumour.
A swelling or a mass of any kind.
Define neoplasia.
New, uncontrolled growth of cells that is not under physiological control. This usually forms a tumour but not all. It can either be benign or malignant.
Define cancer.
Cancer - can be used synonymously with malignant neoplasm. It is a generic term for a large group of diseases characterised by the growth of abnormal cells beyond their usually boundaries that can then invade adjoining parts of the body and/or spread to other organs.
What are the hallmarks of cancer?
Hallmarks of cancer: - Sustaining proliferative signalling - Evading growth suppressors - Avoiding immune destruction - Enabling replicative immortality - Activating invasion and metastasis - Inducing angiogenesis - Resisting cell death Deregulating cellular energetics
What is embryological histogenesis?
Embryological histogenesis The formation of differentiated tissues from undifferenced endoderm, ectoderm and mesoderm cells
What is tumour histogenesis?
Tumour histogenesis The tumours are names according to the tissues form which they arise.
Where cancer arises from squamous cells e.g. in the GIT is called a squamous cell carcinoma. In places of glandular cells become malignant this is called a adenocarcinoma.
If a muscle cell develops a tumour this is called a sarcoma. In smooth muscle this is called leiomyosarcoma and in a skeletal cell this is called rhabdmyocarcinoma. Named according to the tissue or origin.
In pigment cells this is called a melanoma.
Define differentiation.
Differentiation The extent to which the neoplasm resembles its tissue or origin not only in appearance but also in function.
What are the different types of differentiation?
Well-differentiated = neoplasm closely resembles tissue of origin Moderately-differentiated= neoplasm shows some resemblance to tissue of origin Poorly-differentiated= neoplasm does not resembletissue of origin
Define anaplasia.
Anaplasia a neoplasm that is poorly differentiated and highly pleomorphic (lots of cells that show a large amount of variability in cell size and shape).
Which cancer has the highest mortality and incidence in women in the UK?
Highest Incidence - Breast cancer at 31% - followed by Lung (13%) and Bowel (10%)
Highest Mortality - Lung at 21% - followed by Breast (15%) and Bowel (10%)
Which cancer has the highest mortality and incidence in men in the UK?
Highest Incidence - Prostate at 26% - followed by Lung (14%) and Bowel (13%)
Highest Mortality - Lung at 21% - followed by Prostate (14%) and Bowel (10%)
Why are non-melanoma skin cancers not included in the most cancer statistics?
Melanoma pigmented cancer. Relatively rare in comparison to SCC and BCC. SCC and BCC are very common. Since they only represent less than 1 percent of cancer deaths, they tend to be excluded as they behave much more benign the other malignant tumours.
Give differences between benign and malignant tumours.
- Benign neoplasm do not invade surrounding tissue but malignant neoplasms do invade surrounding tissue. In carcinomas the line by which they cross is the basal lamina. Benign tissue therefore have a smooth edge compared to malignant neoplasms which has an irregular invasive edge.
- Benign tumours have a slow rate of growth generally and malignant is fast rate so fast it exceeds cell death
- Generally benign tumours are well differentiated. Malignant tumours tend to show more variation, they show well, moderate, poorly differentiation and can be anaplastic.
- Benign tumours are rarely fatal (except CNS as any tumour leads to compression - of brain tissue) and malignant tumours are often fatal.
What are primary effects of tumours?
- Effects of the primary tumour;
- Invasion into and replacement for normal tissues - > failure of that organ to function such as in the bone marrow and the liver;
- Pressure on normal tissues and so failure of that organ to function especially in the brain;
- Invasion into blood vessels and can cause bleeding;
- Pressure on blood vessels causing ischaemia as you are depriving the organ of blood;
- It can also cause problems by putting pressure or invading into nerves this leads to loss of function or pain
It can also grow into a lumen causing obstruction such as in the colon.
What are effects of distant metastases?
When cancer spreads to different parts of the body forming new secondary tumours. These can then have the potential to cause other problems - Invasion of tissues/pressure/invasion into blood vessels etc.
