Application of adipocyte-related antibodies in undifferentiated sarcomas to identify dedifferentiated liposarcomas based on histological and clinical analysis.

BACKGROUND: Due to morphologic similarities between undifferentiated sarcoma (US) and dedifferentiated liposarcoma (DDLPS), some portions of US could be identified as DDLPS. In this study, we applied adipocyte-related antibodies in order to discriminate possible cases of DDLPS from US. MATERIALS AND METHODS: A total of 46 cases, previously diagnosed as US, were examined. Immunohistochemistry for MDM2, CDK4, calreticulin, FABP4, and stathmin were performed. Histological findings were reviewed and clinical data was analyzed retrospectively. RESULTS: MDM2, CDK4, calreticulin, FABP4, and stathmin were positive in 17 (37.0%), 14 (30.4%), 3 (6.5%), 1 (2.2%), and 12 (26.1%) of the total 46 cases, respectively. MDM2/CDK4 positive cases showed more frequent positivity for calreticulin/FABP4/stathmin. Survival analysis, based on staining pattern, revealed a significantly better survival in the group where either MDM2 and CDK4 were positive and at least one of calreticulin, FABP4, or stathmin staining were positive. CONCLUSIONS: We conclude that when either MDM2-positive or CDK4-positive cases show any other positive results for calreticulin, FABP4, or stathmin, they have a significantly better survival and the possibility of DDLPS should be considered. Additional use of calreticulin, FABP4, or stathmin immunohistochemistry helps us to narrow the pool for further studies such as molecular analysis for a definite diagnosis.