Although KIT and EGFR overexpressions are reported to occur in breast cancer, their pathological significance is still unclear. We examined KIT, EGFR, and c-erbB-2 overexpressions immunohistochemically in 150 cases of surgically resected breast cancer and their correlation with the histological type and grade and mesenchymal and/or myoepithelial immunophenotype of primary tumors. To facilitate the analysis, we constructed a tissue microarray comprising 2-mm diameter tissues cored from the representative tissue block of each tumor. KIT, EGFR, and c-erbB-2 overexpressions were detected in 15 (10%), 12 (8%), and 23 (15%), respectively. The KIT was more frequent in the group comprising comedo-type ductal carcinoma in situ and invasive ductal carcinomas (IDCs) of the solid-tubular subtype than in the group of other histological types (P = 0.027), and the EGFR was more frequent in IDCs of solid-tubular type than in other histological types (P < 0.05). KIT and EGFR overexpressions were correlated with nuclear grade 3 (P = 0.0095 and 0.0005) and tended to be concurrent (P = 0.005). KIT overexpression was correlated with vimentin and S-100 expression (P = 0.003 and P = 0.005), and EGFR overexpression was correlated with S100 expression (P = 0.0001). These correlations with grade and mesenchymal/ myoepithelial markers were not observed for c-erbB-2 overexpression. KIT and EGFR appeared to be indicators of high-grade breast carcinoma groups that often contain the carcinomas with mesenchymal and/ or myoepithelial differentiation, which are distinct from the group with c-erbB-2 overexpression. (Cancer Sci 2005; 96: 48-53)

p53 protein has been frequently detected at high levels in the nuclei of human breast cancer cells. We analyzed inununohistochemically the association between nuclear localization of p53 protein and clinical and histological parameters of breast cancer patients. Surgically resected tissues of 73 primary breast cancers were processed by acetone fixation and paraffin embedding and examined using an anti‐p53 monoclonal antibody, Pabl801. p53 immunoreactivity was detected in the nuclei of cancer cells in 17 cases (23%). The nuclear p53 immunoreaction was closely associated with overexpression of c‐erbB‐2 protein (P<0.05), high histologic grade (P<0.01), advanced clinical stage (P<0.05), and negative estrogen receptor status (P< 0.01). When 31 cases which had been followed up for more than 50 months were examined, a positive nuclear p53 immunoreaction was found to he significantly associated with shorter overall survival of patients (P<0.01). These results suggest that inununohistochemical examination of nuclear p53 protein is clinically useful as an indicator of breast cancer aggressiveness.

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Department of Surgery I, National Defense Medical College, Tokorozawa, Japan Abstract Endocrine therapies that profoundly decrease estrogen levels potentially have a detrimental effect on the cardiovascular system. This study evaluated the effect on lipid metabolism of one such agent, the new generation aromatase inhibitor anastrozole, compared with tamoxifen, when used as adjuvant treatment in postmenopausal Japanese women with early breast cancer. All patients had completed primary surgery and were randomized to anastrozole 1 mg once daily (n 0/22) or tamoxifen 20 mg once daily (n0/22). Anastrozole significantly reduced levels of triglycerides and remnant-like particle cholesterol, whereas tamoxifen significantly increased these. Activity of lipoprotein lipase and levels of high-density lipoprotein cholesterol significantly increased after anastrozole treatment. In contrast, activity of hepatic triglyceride lipase, also a key enzyme of triglyceride metabolism, significantly decreased following treatment with tamoxifen. We thus conclude that in our study anastrozole had a beneficial effect on lipid profiles of postmenopausal women with early breast cancer after 12 weeks of treatment.

A case of primary small cell (oat cell) carcinoma of the breast in a 41-year-old woman is presented. The patient was alive and well without disease 16 months after modified radical mastectomy and subsequent chemotherapy. The tumor cells revealed morphologic similarity to oat cell carcinoma of the lung and immunohistochemical expression of neuroendocrine markers. In ultrastructural examination, the tumor cells had neurosecretory granules. Review of nine previously reported cases and this case of primary small cell carcinoma of the breast has revealed that this type of tumor shows prominent vascular invasion, frequent lymph node metastasis, infrequent expression of estrogen receptor, and also very poor prognosis. Immunohistochemical study for the c-kit proto-oncogene product, which has been reported to be a specific marker for pulmonary small cell carcinoma, demonstrated positive reactivity in approximately 80% of the tumor cells of this case, which is the first report according to our knowledge. The expression of c-kit might be some aid to the diagnosis of primary small cell carcinoma of the breast.