Cyclin E deregulation is an early event in the development of breast cancer
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- Shaye, A., Sahin, A., Hao, Q. et al. Breast Cancer Res Treat (2009) 115: 651. doi:10.1007/s10549-008-0266-0
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Cyclin E has been shown to be overexpressed in some human breast cancers, however, data to support deregulation of cyclin E as an early event in human mammary tumor development is lacking. We analyzed surgical specimens from 183 patients with breast carcinomas and evaluated cyclin E expression in areas of invasive carcinoma, adjacent carcinoma in situ (CIS), and non-neoplastic breast parenchyma. Overexpression of cyclin E was seen in one-third of invasive carcinoma samples, one-third of the CIS component and nearly half of the non-neoplastic breast epithelial cells adjacent to carcinoma (44% vs. 33%, P ≤ 0.05). Nuclear labeling for cyclin E was highly concordant between areas of in invasive carcinoma, CIS and non-neoplastic breast epithelial cells from the same patient (P < 0.0001). Localization of cyclin E to the cytoplasm was seen in a small proportion of tumor samples. Our findings suggest that cyclin E deregulation is an early event in the progression from histologically benign mammary epithelial cells to invasive carcinoma and occurs through both overexpression and altered cellular localization.