Since long time there is a search for a most promising therapy such as chemotherapy, radiation therapy and surgery for the treatment and prevention of cancers. Nowadays antibodies are also gaining importance in the treatment of most types of diseases including cancers. Antibodies are found to be important and most promising and target specific therapeutic agents for cancer due to their epitope specific interaction. Monoclonal antibodies are very specific only one type of epitope. Recently, it has become clear that antibodies possess several clinically relevant mechanisms of action. Many clinically useful antibodies can manipulate tumour-related signaling. In addition, antibodies exhibit various immunomodulatory properties and, by directly activating or inhibiting molecules of the immune system, antibodies can promote the induction of antitumour immune responses. These immunomodulatory properties can form the basis for new cancer treatment strategies.