(P 18) IMMUNOHISTOCHEMICAL ANALYSIS OF NUCLEAR β-CATENIN IN BONE AND SOFT TISSUE TUMOR MICROARRAYS

Objective: We have previously reported the efficacy of a novel agent targeting Wnt signaling in osteosarcoma and synovial sarcoma cell lines and mouse models. In this study, our aim was to assess the frequency of Wnt signaling activity in bone and soft tissue tumors to facilitate the development of therapies targeting Wnt signaling.

Methods: Tissue microarrays containing human bone and soft tissue tumors, as well as normal bone tissue adjacent to the cancer, were utilized to analyze nuclear β-catenin staining, an indicator of Wnt signaling activation, in a total of 432 cases through immunostaining. Desmoid tumors were excluded from this study as they are known to exhibit positive for β-catenin staining. The study encompassed the examination of 58 benign, 50 intermediate (giant cell tumor of bone), 294 malignant tumors, and 30 normal bone tissue cases.

Results: None of the benign bone and soft tissue tumors (0/58), chordoma (0/30), and liposarcoma (0/24) were positive for nuclear β-catenin. Approximately 10% of intermediate or malignant bone and soft tissue tumors, including fibrosarcoma (8/22), osteosarcoma (4/66), giant cell tumor of bone (4/50), and leiomyosarcoma (3/32), were positive for nuclear β-catenin.

Conclusion: Our study suggests that Wnt signaling may be activated in approximately 10% of bone and soft tissue sarcomas.