Cancer occurs when cells divide uncontrollably. These abnormal cells can invade nearby tissues or travel to distant sites by entering the bloodstream or lymphatic system.

For the human body to function normally, each organ must have a certain number of cells. The cells in most organs however have a short lifespan, and to continue functioning the body needs to replace these lost cells by the process of cell division.

Cell division is controlled by genes that are located in the cell nucleus. They function like an instruction manual telling the cell what proteins to make, how it will divide and how long it will live for. This genetic code can get damaged by a number of factors resulting in errors occurring within the instruction manual. These errors can dramatically alter how the cell functions. Instead of resting the cell may continue dividing, instead of dying the cell may stay alive.

A number of mechanisms are in place to prevent genetic errors from occurring and to eliminate genetically abnormal cells from the body. Yet in some people these defences are not enough and an abnormal population of cells that has escaped the bodies control develops. These cancer cells crowd out and destroy normal tissues.

Cancer cells require nutrients to survive and grow. Many types of cancer can stimulate blood vessel growth to provide them with the food they need. In fact the word cancer is derived from the latin word Cancri which means crab. It was thought by the ancients that the large blood vessels surrounding a tumour mass looked like a crabs claws and feet.



Cancer is one of the leading causes of death around the world and accounted for 7.6 million of all deaths in 2008. The main types of cancer leading to overall cancer mortality are:


1.3 million deaths per year


736,000 deaths per year


695,000 deaths per year


608,000 deaths per year


458,000 deaths per year


More than 70% of all cancer deaths in 2008 occurred in low and middle income countries. Deaths from cancer continue to rise, with an estimated 13.1 million dying in 2030.

The most frequent cancer types world wide are:

Among Men

(in order of number of global deaths):

01 Lung
02 Liver
03 Stomach
04 Colorectal
05 Oesophagus
06 Prostate

Among Women

(in order of number of global deaths):

01 Breast
02 Lung
03 Colorectum
04 Cervical
05 Stomach
06 Liver

One-fifth of cancers worldwide can be attributed to chronic infections, mainly from Hepatitis B Viruses HBV (causing liver), Human Papilloma Viruses HPV (causing cervix), Helicobacter Pylori (causing stomach), Schistosomes (causing bladder), The Liver Fluke (bile duct) and Human Immunodeficiency Virus HIV (Kaposi sarcoma and lymphomas).


What Causes Cancer? →

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