Over the period of last decade, many new and non-conventional (i.e. different from chemotherapy) approaches for cancer therapeutics have been emerged as alternative anti-cancer treatment and would have been successful also. However, there are few limitations with these newer approaches like presence of soluble form of antigen in serum, which effectively interfered with the interaction antibody with tumor cell, modulation and loss of the antibody-antigen complexes from the tumor cell surface before antibody mediated killing occur and outgrowth of tumor cells not expressing the antigen. Monoclonal antibodies make an important contribution to the therapeutic treatment of non-Hodgkin lymphoma, acute myeloid leukemia, breast cancer, and now colorectal cancer and prostate cancer.