A real-world study on the expression and clinical application of IMP3 immunohistochemistry in bone tumors

Previous studies have confirmed that insulin-like growth factor 2 mRNA-binding protein 3 (IMP3) is widely expressed in various malignant tumors. However, no systematic study has assessed the expression of IMP3 in bone tumors. We immunohistochemically examined 1381 bone tumor specimens for IMP3 expression, analyzed its differential expression among various types of bone tumors, and evaluated its potential application in surgical pathology. Our results demonstrated that IMP3 positivity was observed in 7.5 % (55/732) of benign bone tumors and 55.2 % (358/649) of malignant bone tumors, with statistically significant differences (P < 0.0001). Notably, higher levels of IMP3 expression were observed in high-grade malignant bone tumors than in their low-grade counterparts. The incidence of IMP3 positivity exceeds 80 % in diffuse large B-cell lymphoma, high-grade osteosarcoma, lymphoblastic lymphoma, and undifferentiated pleomorphic sarcoma. Additionally, we detected IMP3 positivity in 63.5 % (80/126) of metastatic bone cancers, specifically in 83.6 % (46/55) of lung cancers, 70 % (7/10) of liver cancers, and 87.5 % (7/8) of colorectal cancers. We also observed high levels of IMP3 expression in three benign bone tumor types: chondroblastoma, epithelioid hemangioma, and Langerhans cell histiocytosis. In conclusion, IMP3 immunostaining may serve as a diagnostic biomarker for malignant bone tumors, especially osteosarcoma and lymphoma. The high expression of IMP3 observed in bone metastases of lung cancer, liver cancer, and colorectal cancer indicates that IMP3 could be associated with bone metastasis in these malignancies. Future research should focus on elucidating the relationship between IMP3 expression and various clinicopathological parameters as well as prognostic outcomes in malignant bone tumors.