Cancer

 What is cancer?

Definition:  

Cancer is a disease in which some of the body cells grow in uncontrolled fashion and spread to other other parts of body resulting in tumor.

Cancer can start  almost anywhere in the human body which is made of trillions of cells. Normally, the cells of human body grow and multiply, by a process called cell division, to form new cells. When the cells of body are worn out they die and are replaced by new one.

sometimes this orderly process of cell division breaks down and abnormal cells are produce. When the cycle break the cells start dividing in an uncontrolled fashion and form bulk of abnormal cells called tumor. Tumors can be cancerous or non-cancerous(benign).(For all types of cancer click here).

Cancerous tumors can spread and invade into near by body tissues and form tumors in other parts of body (a process called metastasis).Cancerous cells are also called malignant tumors. Many cancer form solid tumors but some type of tumors like leukemias(blood cancer),generally do not.

On the other hand benign tumors do not invade into other body tissues. When removed, benign tumors usually do not grow back. Benign tumors can sometimes be quite large. Some benign tumors are also life threatening, such as benign tumor in brain.