Cancer is characterized by uncontrolled growth and spread of cancer cells into normal tissues, causing their dysfunction [1]. 

More than 200 different cancers have been identified so far [2]. While some cancers have links with infectious agents, such as cervical cancer linked to human papilloma virus infections, other have no known infectious agents associated with them. Nevertheless, a hallmark feature of all cancer is the ability of cancer cells to evade immune recognition and immune-mediated destruction. Both, innate and adaptive immune responses have potential for anti-tumor responses yet cytotoxic T cells (CTLs) and natural killer (NK) cells are considered the most potent anti tumor effector cells. Specific augmentation of immune response towards cancer cells by cancer immunotherapy has shown great success in treatment of cancer and remains a focus for oncologists, immunologists and drug developers.