Caner is a disease affecting the cells that make up the tissues of the body.  For a normal individual, the cells in the body divide in a controlled fashion.  But if the cell reproduction process goes out of control, the cell will divide constantly, growing into a lump called tumor.

      Tumors can be classified as either benign or malignant. Benign tumors do not spread to other parts of the body and so they are not considered cancerous. Malignant tumors can spread to other organs and tissue of the body.  Therefore they are cancerous.  Left untreated, malignant tumors destroy surrounding cells and tissues.  When malignant tumor cells reach a new body site and starts dividing,  it is referred to as metastasis.

     Often, a biopsy if performed to determine if a tumor is benign or malignant.  It is done by examining a sample of target cells under a microscope.