Cancer

Our bodies are made up of millions of tiny cells. Most of our cells divide and multiply from time to time - when an old cell is worn out or damaged, a new cell is formed to replace it. Each cell contains genes (made up from our DNA). The proteins inside the gene control when the cell should divide and multiply. If the gene is damaged or altered (maybe because too much or too little protein is being made) the cell becomes ‘abnormal’. This abnormal cell can then divide and multiply, without knowing when to stop. When a group of abnormal cells clump together and grow a ‘tumour’ forms.

There are two types of tumour: benign and malignant. Benign tumours are not cancerous, and won’t invade or spread to other parts of the body. Whereas malignant tumours are the real cancers. They can grow very quickly, invade nearby tissues and organs, and cause damage. They may even spread to other parts of the body and cause secondary tumours (metastases). But not all cancers form solid tumours - cancers of the blood, like leukaemia, develop from abnormal blood cells, which then attack other areas of the body by circulating in the bloodstream.

There are two broad categories of cancers. Cancers that develop in the surface linings of organs are called ‘carcinomas’. Cancers that appear in the cells of solid tissues, such as muscles, bones and blood vessels are called ‘sarcomas’. Carcinomas are the most common.

There are about 200 different types of cancer. Some types are more serious than others, some are more easily treated, and others have better survival rates. Sadly, many of us will be affected by cancer at some point in our lives. If you are diagnosed with cancer, the doctors will need to find out what type you have, and if it has spread. That way they can decide on the best course of treatment for you.

 

More

http://dir.yahoo.com/Health/Diseases_and_Conditions/Cancers/

http://www.apha.org/public_health/cancer.htm

http://www.lib.uiowa.edu/hardin/md/oncol.html