Mdm2 and p53 expressions and Ki-67 proliferative index in fibrohistiocytic tumors

Objective: Various genetic alterations including inactivation of tumor suppressor genes and activation of oncogenes, are described in different types of neoplasms as well as soft-tissue tumors. The purpose of the present study is to evaluate the expressions of mdm2 and p53, and Ki-67 proliferative activity and to investigate their interrelations with the clinicopathologic parameters in fibrohistiocytic soft tissue tumors. Study design: Of the 43 patients diagnosed as fibrohistiocytic tumors including 30 fibroblastic neoplasms and 13 undifferentiated pleomorphic sarcomas were studied. All slides were stained with mdm2, p53 antibodies and Ki-67 by using the standard biotin immunoperoxidase method. Nuclear staining was scored semiquantitatively for all of the cases. Results: p53 and mdm2 expressions were observed in 47.5% and 20% of the whole tumors, respectively. No association was found between p53 and mdm2 expressions and the clinicopathologic parameters; whereas, there was statistically significant difference between fibroblastic neoplasms and undifferentiated pleomorphic sarcomas in terms of p53 and mdm2 expressions. Ki-67 index showed a statistically significant relation with tumor grade and expression of p53 protein. Ki-67 values were also significantly different between fibroblastic neoplasms and undifferentiated pleomorphic sarcomas. Conclusions: Our results support the idea that mdm2 and p53 expressions indicate tumorigenic potential in soft tissue tumors. The expressions of p53 and mdm2 proteins and Ki-67 proliferative index in fibrohistiocytic tumors seem to be useful markers for differential diagnosis.