ABSTRACT
AIM AND BACKGROUND: It has been recently demonstrated that the detection of stem cell niches in triple-negative (TN) breast cancer may provide good prognostic clues for this tumor. METHODS AND STUDY DESIGN: We investigated the subcellular expression and localization of the cancer stem cell marker CD133 in a TN breast cancer biopsy from a 42-year-old Caucasian woman with a histological diagnosis of high-grade invasive ductal breast carcinoma by immunohistochemistry, flow cytometry and quantitative real-time PCR (qRT-PCR). RESULTS: We describe for the first time in a TN breast cancer the nuclear mislocalization of CD133, which normally shows membrane localization and more sporadically cytoplasmic localization. We also found this aberrant expression with qRT-PCR analysis but not flow cytometry. CONCLUSIONS: Nuclear localization of CD133 may be an indicator of poor prognosis in TN breast cancer, as it is known that surface molecules, when moving into the nucleus, can act as transcriptional regulators by interfering with molecular pathways directly connected to the proliferation and differentiation of tumor cells.
