Fig. 3

Modalities of immunotherapy in bladder cancer. BCG is a weakened strain of Mycobacterium bovis and was the first of immunotherapy approved for BC. NMIBC patients with high risk of recurrence are subjected to BCG therapy. The administration of BCG leads to a stimulation of both adaptative and innate immune response by recruiting lymphocytes, macrophages, NK cells and neutrophils, leading to the elimination of the remaining tumor cells. On the other hand, BC patients with MIBC are candidates for immune checkpoint blockage. Tumor cells express repression signals that lead to the inhibition of the immune response, namely by expressing PD-L1/PD-L2 and B7-1/B7-2, that will bind to PD-1 and CTLA-4 present in T lymphocytes, respectively. Nevertheless, with the administration of antibodies against PD-1, PD-L1 or CTL4-A, this process is reverted, leading to the activation of T cells and the start of an immune response against tumor cells, leading ultimately to their death