Immune and inflammatory profiling in bladder cancer: Insights into biomarkers and therapeutic strategies.

861 Background: This study aimed to characterize and compare the profiles of inflammatory and immune responses (IFN-γ, CX3CR1, iNOS, PD-L1, CTLA-4, CD163, FOXP3), monoamine oxidases (MAO-A and MAO-B), and the expression of HABP4 (hyaluronan-binding protein 4) and SERBP1 (Serpine1 mRNA-binding protein 1) in bladder tissue samples from patients with initial non-muscle-invasive bladder cancer (NMIBC), BCG-unresponsive NMIBC, and muscle-invasive bladder cancer (MIBC). Additionally, we aimed to provide an overview of the involvement of these factors and their signaling pathways in the tumor microenvironment (TME) of bladder cancer (BC). Methods: A total of 60 formalin-fixed, paraffin-embedded bladder cancer samples were obtained from patients diagnosed with BC at the Paulínia Municipal Hospital and São Vicente de Paulo Charity Hospital, Brazil. The samples were classified into three groups (n= 20 samples per group): Group 1 – initial NMIBC, Group 2 – BCG-unresponsive NMIBC, and Group 3 – MIBC. Immunohistochemical analysis was performed to evaluate the expression of target markers. Results: MAO-A immunoreactivity was significantly elevated (p<0.05) in Groups 1 and 2 compared to Group 3. In contrast, MAO-B expression was significantly higher (p<0.05) in Groups 2 and 3 compared to Group 1. These findings suggest that MAO-A serves as a potential biomarker for superficial disease, whereas MAO-B may be associated with disease progression. Elevated levels of CTLA-4 and PD-L1 were observed in Group 1 relative to Groups 2 and 3 (p<0.05), indicating that BCG treatment reduces their immunoreactivity in both BCG-unresponsive NMIBC and MIBC phenotypes, thereby modulating the TME. Additionally, immunoreactivities of CD163 and FOXP3 were significantly increased (p<0.05) in Group 2, followed by Group 3, implying that FOXP3 + regulatory T cells and CD163 + M2 macrophages contribute to BCG treatment failure and tumor progression. Conversely, IFN-γ, CX3CR1, and iNOS expression were significantly elevated (p<0.05) in Group 1, indicating that a heightened infiltration of CX3CR1 + cells and iNOS + M1 macrophages creates a cytotoxic microenvironment more responsive to immunotherapeutic interventions. This study represents the first report of HABP4 and SERBP1 immunoreactivities in BC. SERBP1 expression was significantly higher (p<0.05) in Groups 2 and 3, linking its overexpression to tumor progression. In contrast, HABP4 expression was significantly elevated (p<0.05) in Group 1 compared to Groups 2 and 3, supporting its role in inhibiting cell proliferation. Conclusions: These findings suggest that analyzing markers such as MAO-A, MAO-B, HABP4, and SERBP1 can improve risk stratification, prognosis, and personalized therapies for BC patients, particularly in the context of immunotherapies. Identifying specific profiles in the TME can guide more effective, tailored treatments and enhance clinical outcomes.