What is Cancer?

The human body is made up of over 3 trillion cells. Periodically, under the control of cell cycle regulators, these cells divide to form new cells, replacing the old or damaged cells.

Under rare instances, one of these cells might overcome the cell cycle regulation and divide uncontrollably which can disrupt the body's normal functioning.

Such abnormal cell growth may result in several related diseases, collectively known as cancer. If the spread of cancer cells is not contained, it will result in the organism’s death.

So, how does a normal cell turn cancerous? Almost every cell in a human body experiences genetic mutations. Although most of these nucleotide changes are repaired by the DNA repair enzymes, some mutations remain unchecked.

In rare instances, such unrepaired mutations may allow a cell to divide faster and survive longer than the surrounding cells.

Overtime, these mutant cells proliferate, prosper and form a visible mass of cells called tumors that are broadly categorized into two types.

Benign tumors are confined to the tissue of origin. They are usually harmless and can be surgically removed.

On the other hand, malignant tumors can break off from the primary site, invade far away tissues and form another tumor, by a process called Metastasis - a hallmark of a cancerous tumor. This entire process of transformation of a normal cell into a cancerous cell is called oncogenesis.

Cancer can arise in almost any part of the body. For example, the uncontrolled proliferation of white blood cells causes leukemia, the unhindered growth of cells from the large intestine results in colon cancer, and the abnormal cell division of soft tissues like tendons, cartilage, or muscles is referred to as sarcoma.