of the Well-differentiated Component

Alteration of the p53/mdm2 pathway has been reported in the well-differentiated ii-posarcoma (WDLS)/dedifferentiated liposarcoma (DDLS) group. We investigated the immunoreactivity of p53, mdm2, and p2IWAF1, along with the MIB-I-labeling index (MIB- 1-LI) in 21 WDLS and 21 DDLS cases, to clarify the association of these mark-ers with the morphologic changes and the biological factors responsible for the ag-gressiveness of DDLS. Within DDLS, p53 and p21WAF1 expression and mdm2 overex-pression were significantly more prevalent in the dedifferentiated (DD) components than in the well-differentiated (WD) components. The mdm2 overexpression and p2lWAFi expression was significantly associated with sclerosing liposarcomas in both WDLS and the WD components of DDLS. There was no significant difference in the immunoreactivity of p53, mdm2, or p21WAF1 or MIB-1-LI between WDLS and the WD components of DDLS. An association was found between p53 expression and mdm2 overexpression in the WD group (comprising WDLS and WD components of DDLS) and in the DD group, significantly so in the WD group. Notably, this correla-tion was found in the subtype of sclerosing liposarcoma but not in that of lipoma-like liposarcoma. Within DDLS, the clinical outcome of the nonaccessible soft tissue (non-AST: comprising retroperitoneum and mediastinum) group was significantly worse than that of the accessible soft tissue (AST: comprising extremities, buttocks, axilla, and scrotum) group; however, the immunophenotypes of p53, mdm2, and p21WAF1 and the MIB- 1-LI showed no correlation with survival in the AST group alone, in the non-AST group alone, or in the 2 together. This study suggests that the immunore-activity of p53, mdm2, and p2iWAFi is associated with the morphologic changes, but not with the biological factors responsible for the aggressiveness of DDLS. Int J Sur