Prognostic role of CD74, CD10 and Ki-67 immunohistochemical expression in patients with diffuse malignant peritoneal mesothelioma: a retrospective study

BACKGROUND: Diagnosis and treatment of diffuse malignant peritoneal mesothelioma (DMPM) are still challenging. The aim of the present study was to explore the correlation between CD74, CD10, Ki-67 and clinicopathological parameters, and identify independent prognostic factors of DMPM. METHODS: Seventy patients with pathologically proven DMPM were retrospectively reviewed. The expression of CD74, CD10 and Ki-67 in peritoneal tissues was detected by immunohistochemical analysis using standard avidin biotin complex (ABC) immunostaining technique. Kaplan-Meier survival analysis and multivariate Cox regression analyses were performed to assess prognostic factors. The nomogram based on the Cox hazards regression model was established. C-index and calibration curve were performed to evaluate the accuracy of nomogram models. RESULTS: The median age of DMPM was 62.34 years, and the male-to-female ratio was 1: 1.80. CD74 expression was identified in 52 (74.29%) of 70 specimens, CD10 in 34 (48.57%) specimens, and higher Ki-67 in 33(47.14%) specimens. CD74 was negatively associated with asbestos exposure(r = -0.278), Ki-67(r = -0.251) and TNM stage(r = -0.313). All patients were effectively followed up in the survival analysis. Univariate analysis revealed that PCI, TNM stage, treatment, Ki-67, CD74 and ECOG PS were associated with DMPM prognosis. CD74 (HR = 0.65, 95%Cl:0.46–0.91, P = 0.014), Ki-67(HR = 2.09, 95%Cl:1.18–3.73, P = 0.012),TNM stage (HR = 1.89, 95%Cl:1.16–3.09, P = 0.011), ECOG PS(HR = 2.12, 95%Cl:1.06–4.25, P = 0.034), systemic chemotherapy (HR = 0.41, 95%Cl:0.21–0.82, P = 0.011) and intraperitoneal chemotherapy (HR = 0.34, 95%Cl:0.16–0.71, P = 0.004) were independent predictors by multivariate Cox analysis. The C‑index of the nomogram for predicting overall survival (OS) was 0.81. The OS calibration curve showed good agreement between nomogram-predicted and observed survival. CONCLUSIONS: CD74, Ki-67, TNM stage, ECOG PS and treatment were independent factors affecting prognosis of DMPM. Reasonable chemotherapy treatment might improve the prognosis of patients. The proposed nomogram was a visual tool to effectively predict the OS of DMPM patients.