The role of immunotherapy in urologic malignancies

Immunotherapy of malignant brain tumors

Despite aggressive multi-modality therapy including surgery, radiation, and chemotherapy, the prognosis for patients with malignant primary brain tumors remains very poor. Moreover, the non-specific nature of conventional therapy for brain tumors often results in incapacitating damage to surrounding normal brain and systemic tissues. Thus, there is an urgent need for the development of therapeutic strategies that precisely target tumor cells while minimizing collateral damage to neighboring eloquent cerebral cortex. The rationale for using the immune system to target brain tumors is based on the premise that the inherent specificity of immunologic reactivity could meet the clear need for more specific and precise therapy. The success of this modality is dependent on our ability to understand the mechanisms of immune regulation within the central nervous system (CNS), as well as counter the broad defects in host cell-mediated immunity that malignant gliomas are known to elicit. Recent advances in our understanding of tumor-induced and host-mediated immunosuppressive mechanisms, the development of effective strategies to combat these suppressive effects, and a better understanding of how to deliver immunologic effector molecules more efficiently to CNS tumors have all facilitated significant progress toward the realization of true clinical benefit from immunotherapeutic treatment of malignant gliomas.

Adoptive immunotherapy for malignant glioma

Despite remarkable advancements in imaging modalities and treatment options available to patients diagnosed with malignant brain tumors, the prognosis for those with high-grade lesions remains poor. The imprecise mechanisms of currently available treatments to manage these tumors do not spare damage to the normal surrounding brain and often result in major cognitive and motor deficits. Immunotherapy holds the promise of offering a potent, yet targeted, treatment to patients with brain tumors, with the potential to eradicate the malignant tumor cells without damaging normal tissues. The T cells of the immune system are uniquely capable of recognizing the altered protein expression patterns within tumor cells and mediating their destruction through a variety of effector mechanisms. Adoptive T-cell therapy is an attempt to harness and amplify the tumor-eradicating capacity of a patients' own T cells and then return these effectors to the patient in such a state that they effectively eliminate residual tumor. Although this approach is not new to the field of tumor immunology, new advancements in our understanding of T-cell activation and function and breakthroughs in tumor antigen discovery hold great promise for the translation of this modality into a clinical success.