Slide 1
Growth has rules
Cancer develops when cells acquire changes that let them grow and survive outside normal controls. It is a group of diseases, not one uniform condition.
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Healthy tissues regulate when cells divide, repair damage or die. Cancer can disrupt several of these controls, so uncontrolled growth is an outcome of altered regulation rather than a single switch.
Slide 2
Different genes play different roles
Some changes increase growth signals; others weaken restraints or DNA repair. Several kinds of genetic disruption can contribute to cancer.
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An inherited variant can increase susceptibility, but many cancer-related changes arise during life. Calling cancer genetic does not mean every cancer was inherited from a parent.
Slide 3
A tumour is not automatically malignant
A tumour is an abnormal mass of tissue. Benign tumours do not invade and spread in the same way as malignant ones.
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Some cancers, including many blood cancers, do not form a single solid mass. The presence or absence of a lump therefore cannot define the whole category.
Slide 4
Spreading requires further steps
Metastasis occurs when cancer cells establish growth away from the original site. Traveling cells must survive several barriers along the way.
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A cancer that spreads to another organ retains the identity of its origin in clinical naming. Breast cancer in the lung is not thereby transformed into a new primary lung cancer.
Slide 5
One tumour can contain variation
Cancer cells within the same tumour can differ genetically. This variation can influence how a disease behaves and responds to treatment.
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The surrounding blood vessels, immune cells and connective tissue also matter. Researchers study this microenvironment because cancer develops within a tissue system rather than in isolation.
Sources
- What Is Cancer?
National Cancer Institute
- The Genetics of Cancer
National Cancer Institute