Background: Tumor-infiltrating lymphocytes influence the prognosis of solid tumors, including ovarian cancer (OC). The immunoregulatory transcription factor (IRF4) is mainly expressed in plasma cells and regulates immunoglobulin class switch recombination as well as plasma cell differentiation. Therefore, we analyzed the impact of IRF4 expression in a consecutive cohort of OC patients.
Methods: IRF4 expression was evaluated by immunostaining. Differences in IRF4 expression among the subgroups of the established clinical-pathological features like age, histological subtype, tumor stage, histological grading, postoperative tumor burden, and completeness of chemotherapy were determined by χ2 test. The impact of IRF4 expression on progression-free survival (PFS) and overall survival (OS) was examined by univariate and multivariate Cox analysis adjusted for established clinical-pathological factors and Kaplan-Meier survival analysis.
Results: 114 patients entered this study. IRF4 was expressed in 51.7% of the entire cohort. 72.3% patients with high-grade serous OC showed IRF4 expression compared to 37.3% patients with a non-high-grade serous OC (p < 0.001). Univariate Cox-regression analysis revealed no prognostic impact of IRF4 expression in terms of PFS (p = 0.35) and OS (p = 0.98). Kaplan-Meier plots failed to show any prognostic impact for PFS (p = 0.35) and OS (p = 0.98), too. Established clinical-pathological factors retained their prognostic impact as tumor stage in terms of PFS (< 0.001) and as postoperative residual tumor burden (p = 0.04), tumor stage (< 0.001), histological grade (p = 0.02), and completeness of chemotherapy (p < 0.001) in terms of OS, respectively.
Conclusion: Immunohistochemically determined IRF4 expression correlated with high-grade serous OC. However, it failed to show any prognostic impact in this cohort of 114 patients.
Keywords: Antitumor immunity; IRF4; Ovarian cancer; TILs.