Cancer Chemotherapy and Immune Regulation

Problem statement: Chemotherapeutic drugs have been used to treat malignancy for over 50 years, but the potential of cytotoxic agents to suppress immunity and interfere with Immunosurveillance (IS) of cancer has been largely ignored. Assuming that the immune control of the cancer had a priori already failed, the effect was not considered to have a major impact on treatment outcome. Approach: We reviewed the literature of what is known about the effect of anti-cancer on immune function and their effects. Results: Increasing evidence suggested a role for tumor specific lymphocytes, as evidenced by the Graft-versus-Leukemia effect after allogeneic stem cell transplantation and infiltrating tumor-specific lymphocytes. A strong relationship between robust lymphocyte recovery after chemotherapy and favorable outcome, further suggested that cell mediated immunity played an important role in preventing disease recurrence after bulk reduction of the tumor by cytotoxic agents. Conclusion: We were beginning to discover mechanisms whereby cancer treatments favorably affect interactions between the immune system and the malignancy. However, at present our ability to use cancer chemotherapy to reboot the immune system in a controlled fashion was limited. Future strategies may allow us to more efficiently link cancer treatments with immune function, not only restoring but further enhancing IS by boosting T lymphocyte and Natural Killer (NK) cell recovery, increasing tumor susceptibility to T cell or NK cell attack and inducing Tumor-Specific Antigen (TSA) specific T cell responded with vaccines.