High Immunohistochemical Expression of SETD5 as a Candidate Pathological Factor for Dedifferentiation and Prognosis in Liposarcoma

SET domain containing 5 (SETD5), a chromatin regulator involved in adipocytic differentiation, has been identified in various cancers, but its immunohistochemical expression and prognostic significance in liposarcoma remain unclear. This study examined the immunohistochemical expression and prognostic significance of SETD5 in liposarcomas. SETD5 expression was analyzed in 100 adipocytic tumors using immunohistochemistry; these 100 tumors consisted of 24 dedifferentiated liposarcomas (DDLPS), 24 atypical lipomatous tumors/well differentiated liposarcomas (WDLPS), 12 myxoid liposarcomas, 5 pleomorphic liposarcomas, and 35 benign adipocytic tumors. SETD5 expression was assessed using the immunoreactivity score and its prognostic significance was investigated. SETD5 expression was absent in normal adipose tissue and minimal in lipomas. SETD5 expression was significantly higher in WDLPS than in lipomas (p = 0.01). Moreover, SETD5 expression was markedly elevated in the dedifferentiated component of DDLPS compared to the well-differentiated component (p < 0.001). Pleomorphic liposarcoma showed the highest SETD5 expression levels. In DDLPS, high SETD5 expression in the dedifferentiated component correlated with worse overall survival (p < 0.001) but was not correlated with disease-free survival (p = 0.086). Immunohistochemical expression of SETD5 significantly correlates with prognosis in DDLPS and may serve as a candidate pathological factor for dedifferentiation and prognosis.