In our daily life, we come across the word 'cancer' quite often. It is the unspoken fear of every one of us. Once a rare disease, cancer is spreading fast in the modern world.But what is cancer? What does this actually mean? The human body is made up of small bricks called 'cells'. There are trillions of microscopic cells in our body. These are the basic unit of life. Cells die, and are born on daily basis. Cancer is the abnormal production of these cells. As a result of abnormal cells, functions in the human body are disturbed leading to death if not caught early.Cancer can be of two types. it can be 'malignant' i.e. spreading to other body parts; or it can be 'benign' i.e. localized to only one particular body part. The latter one is less feared and is easy to treat. If the cancer is malignant, it requires more aggressive and in time treatment.