C-KIT expression in columnar cell lesions of the breast accompanied by benign and malignant breast diseases

Columnar cell lesions (CCLs) of the breast are reported with increasing frequency. However, the significance of these lesions and the treatment approach to these lesions are still unknown. The aim of the present study was to evaluate c-KIT expression in CCLs accompanying benign and malignant breast diseases. A total of 65 patients (18 benign breast diseases, 8 ductal carcinomas in situ (DCI), and 39 invasive carcinomas) were included in the study. c-KIT was strongly expressed in normal breast epithelium (staining intensity; SI: 3 +/- 0.0), whereas a heterogeneous and cytoplasmic staining pattern was observed in CCLs accompanying both benign and malignant diseases. c-KIT expression was decreased, with increasing atypia in CCLs (SI in CCLs with/ without atypia; 1.45 +/- 0.52/no case, 1.25 +/- 0.50/1.38 +/- 0.52, 0.77 +/- 0.73/1.21 +/- 0.42 accompanying benign breast disease, DCI and invasive carcinoma, respectively). c-KIT expression was detected in 10.4% of invasive carcinomas. No significant association between c-KIT expression and the histologic grade and nodal status of tumor was noted. As there is a reduction in c-KIT expression with malignant transformation of breast epithelium, c-KIT is believed to play a role in breast carcinogenesis. Furthermore, similar c-KIT expression patterns in CCLs accompanying malignant breast diseases suggest that at least some CCLs could reflect a premalignant status of breast carcinoma. However, the significance of c-KIT expression in CCLs and its relationship to breast carcinogenesis should be evaluated in follow up studies investigating larger series. (C) 2007 Elsevier GmbH. All rights reserved.