Comparative evaluation of leucine-rich repeat kinase 2 and isthmin-1 immunoreactivity in malignant mesothelioma and reactive mesothelial hyperplasia

Abstract

Aims: This study was designed to investigate the immunohistochemical expression Leucine-Rich Repeat Kinase 2 (Dardarin, LRRK2) and Isthmin-1 (ISM-1) in tumor tissues from patients with MM, alongside a comparison to reactive mesothelial hyperplasia (RMH). Methods: A total of 60 MM and 60 RMH cases who had not received preoperative adjuvant therapy were included in the study. Immunohistochemical staining for LRRK2 and ISM-1 were conducted on 4-6 μm thick sections prepared from formalin-fixed, paraffin-embedded blocks. Results: Histopathological examination of MM cases revealed neoplastic formations with tubulopapillary architecture lined by mesothelial cells exhibiting moderate nuclear atypia and eosinophilic cytoplasm. In RMH cases, proliferating mesothelial cells lining an inflamed, edematous, and congested pleural surface were observed. Immunohistochemical analysis demonstrated that ISM-1 and LRRK2 expression levels were markedly elevated in MM tumor samples compared with RMH samples (p<0.001). Conclusion: Both LRRK2 and ISM-1 immunoreactivity were increased in malignant mesothelioma compared with RMH. However, the potential regulatory effects of these molecules on each other’s expression remain unclear. These results indicate that LRRK2 and ISM-1 could be clinically useful biomarkers for distinguishing MM from RMH and may also have potential prognostic value, highlighting the need for further research.