Immunohistochemical evaluation of the c-kit proto-oncogene in sarcomas of the uterus: a case series.

OBJECTIVE: To evaluate the incidence of c-kit expression in uterine sarcomas. STUDY DESIGN: Immunohistochemical evaluation for expression of c-kit was performed on specimens from 11 patients with pathologically documented uterine sarcomas. Histologic subtypes included 5 carcinosarcomas, 3 leiomyosarcomas and 3 endometrial stromal sarcomas. Histologic sections of formalin-fixed, paraffin-embedded hysterectomy specimens from patients with uterine sarcomas were immunostained with c-kit (CD117) antibody. Overall staining intensity was graded as strong, intermediate or weak. RESULTS: In all 11 patients with uterine sarcoma, c-kit immunostaining was positive. Four specimens demonstrated stronger staining intensity than did the gastrointestinal stromal tumor control. Five specimens demonstrated intermediate staining intensity. Two specimens demonstrated weak staining intensity. Furthermore, in the carcinosarcoma specimens both the epithelial and sarcomatous elements were positive for c-kit staining. CONCLUSION: In this case series, c-kit expression was demonstrated in all sarcomas of the uterus regardless of histologic type. These results suggest that such drugs as imatinib mesylate, which inhibit the c-kit tyrosine kinase, should be investigated for these mesenchymal neoplasms.