Cancer
Cancer represents the abnormal growth and division of a
population of abnormal cells
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Introduction
Normal cells undergo repetitive cycles of growth and division. In so
doing, they allow for the expansion and maintenance of existing cell
populations within the human body. This is balanced by the orderly
death of older or damaged cells, a process called apoptosis. These
competing forces allow for the regulation of a fairly stable cell count in
the body.
What is Cancer?
Cancer in contrast, can be viewed as the abnormal expansion of a
population of abnormal cells. This can be due to excessive proliferation
or reduced loss of cells. The net result is an accumulation of cells over
time. This leads to the formation of an abnormal mass in the affected
tissue known as a tumour, or an abnormal population of cells in the
blood. Cancer therefore represents a deviation from the normal
regulatory processes within a cell.
These abnormal populations exhibiting excessive growth often occur due
to mutations that block apoptosis or enhance cell proliferation. In
addition, these cells are often genetically unstable and therefore prone
to further mutations, which make them increasingly abnormal and
unstable. For example, further mutations may confer additional loss of
growth control, immortalization or an enhanced ability to invade local
tissues or to metastasize to distant sites.
It should be remembered that not all tumours are cancerous. Benign
tumours lack the ability to spread by invasion into adjacent areas or by
metastasizing to distant parts of the body. As a result they are often not
life threatening. In contrast, a malignant tumour can spread by both
invasion and metastasis. It is these latter tumors that are correctly called
cancer. Their ability to spread often poses significant health
consequences as they disrupt not only local structures but also distant
tissues and organs, often leading to impaired function.
Conclusion
Cancer cells possess certain characteristics, which represent various
disturbances of cellular processes. These include the following:
- Accumulated mutations that lead to genetic instability.
- Uncontrolled proliferation
- Impaired cell death
- Ability to replicate indefinitely
- Ability to spread locally or to distant sites
Summary
Cancer is the abnormal expansion of a population of abnormal
cells. These abnormal populations often occur due to mutations
that block cell death or enhance cell growth.
The information above is to be used for general information only.
All personal and health care decisions are to be made in
consultation with the appropriate personnel.
Last Updated 07.8.20
© Dr Simons
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