Markers of apoptosis and angiogenesis indicate that carcinomatous components play an important role in the malignant behavior of uterine carcinosarcoma.

Carcinosarcoma of the uterine body is a relatively uncommon neoplasm that contains carcinoma components (CCs) and sarcoma components (SCs). Which component is responsible for the aggressive biologic behavior of this tumor has been a matter of discussion. Recently, many studies have indicated that angiogenesis and apoptosis play an important role in the biologic behavior of tumors. The aim of this study was to clarify, through the exploration of angiogenesis and apoptosis, which compartment is more important for the biologic behavior of carcinosarcoma. Paraffin sections from 10 uterine carcinosarcomas were stained by using anti-CD34 monoclonal antibodies for quantifying tumor vascularization. DNA nick was labeled immunostained by using an Apop Tag in situ apoptosis detection kit for exploring apoptosis. In addition, immunohistochemical staining for Ki-67 labeling index (LI) was conducted for evaluating cell proliferation. Although there was no significant difference in Ki-67 LI between SCs and CCs (P = .06), the microvessel density (MVD) in CCs was significantly higher than in SCs (P = .003), and the apoptotic index (AI) was significantly higher in SCs than in CCs (P = .002). Accordingly, CCs may play an important role in aggressive biologic behavior in carcinosarcoma. HUM PATHOL 31:1448-1454.