Tumors are made up of lumps or growth of defective cells. These may attach themselves to organ tissues, bone or even muscles. The lump is referred to as a cancerous tumor. Tumors may either be classified as benign or malignant based on the progressive growth. A benign tumor is non cancerous while a malignant one is. The malignant tumors through a process called metastasis are capable of travelling to different parts of the body and attaching themselves there. They then commence their growth process. The benign tumors are dormant and really do not present much threat.
The precision targeting and destruction of the malignant tumors is the major headache in our desire to cure cancer. The malignant cells attach themselves to sensitive tissues and organs e.g the brain, lungs, colon, breast etc. An attack on these tissues may lead to other undesirable damages to these organs and hence hindering their optimal function. Its like dropping a nuclear bomb in a small village to kill a fly! The fly may be killed but the destruction on the village may be even worse.