Expression of c-kit (CD117) in benign and malignant human endometrial epithelium.

BACKGROUND: The proto-oncogene c-kit encodes a tyrosine kinase receptor (CD117) with a molecular weight of 145 kd. Previous studies, predominantly utilizing immunohistochemistry, have led to contradictory findings regarding the expression of CD117 in the endometrium. To help resolve this issue, we analyzed a series of benign and malignant endometrial tissues using both immunohistochemistry and Western blot analysis. OBJECTIVE: To examine the expression of CD117 in benign and malignant human endometrial tissues. METHODS: The expression of CD117 in 35 benign endometrial tissues (7 hyperplastic, 14 proliferative, 14 secretory) and 10 endometrioid carcinomas was investigated by immunohistochemistry (clone K45 monoclonal antibody). Immunoprecipitation (clone K69 monoclonal antibody) followed by Western blotting (clone K45 monoclonal antibody and clone 1.D9.3D6 monoclonal antibody) was performed to confirm CD117 expression. RESULTS: Fifty-seven percent of the hyperplasias, 93% of proliferative endometria, and 79% of secretory endometria immunostained positively for CD117. In benign endometria, epithelial staining tended to be more intense in the hyperplastic and proliferative endometria as compared to the secretory endometria, whereas endometrial stromal cells were not immunoreactive. Of the 10 frozen endometrial tissues analyzed by immunohistochemistry, 4 of 9 endometrioid carcinomas and a single case of an endometrioid polyp developing in association with a carcinoma expressed CD117. Immunoprecipitation followed by Western blot analysis confirmed expression of full-length CD117 in an endometrial polyp and carcinoma, and revealed a correlation between levels of immunoprecipitated CD117 and immunohistochemical staining intensity. CONCLUSIONS: Benign and malignant endometrial tissues express CD117. Our data suggest (a) a possible relationship between estrogen and CD117 expression in benign endometrium and (b) potential involvement of this growth factor receptor in endometrial carcinogenesis.

Aspiration and imprint cytopathology of salivary duct carcinoma.

BACKGROUND: Salivary duct carcinoma (SDC) is a highly malignant primary epithelial neoplasm of the salivary glands. The histology of this lesion resembles that of cribriform and comedo-type intraductal carcinoma of the breast, yet the cytopathology of salivary duct carcinoma has been described in only a few instances in the past. METHODS: The authors report two cases of SDC diagnosed by fine-needle aspiration biopsy and one case imprinted after resection. The cytologic features that may permit diagnosis of this entity are described. RESULTS: Cytologic features include variably cellular smears containing loose clusters of cribriform and glandlike aggregates; monomorphic polygonal cells with round-to-oval nuclei; abundant, finely granular cytoplasm; indistinct nucleoli; and variable necrosis. CONCLUSIONS: The cytologic findings for SDC are relatively unique and may allow for its specific diagnosis on aspiration cytopathology.