Aberrant Expression of Cancer Stem Cells Marker Prominin-1 in Low-Grade Tubulobular Breast Carcinoma: A Correlative Study between qRT-PCR, Flow-Cytometric and Immunohistochemistry Analysis

PURPOSE: Prominin1/CD133 has become the ideal marker for cancer stem cells (CSCs) detection in human tumors. In this study we examined the expression of this marker in several breast cancer specimens to associate CSCs percentage with risk factor for this neoplasia. METHODS: We examined specimens from 12 patients using CD133 and CD44 antibodies for CSCs immunohistochemistry detection and for flow cytometry analysis. For each patient, we also performed the immunohistochemical staining to evaluate the expression of estrogen receptor, progesterone receptor, c-erbB-2, Ki67, and E-cadherin markers. A Taqman probe for CD133 was used for mRNA quantification by real-time polymerase chain reaction. RESULTS: Prominin-1 expression was heterogeneous in different carcinomas but was strikingly hyperexpressed in a tubulolobular variant of breast cancer. The results were confirmed by all three methods. CONCLUSION: Our data, although produced on a limited number of samples, showed an particularly high expression of stem cell marker CD133 in a breast cancer variant, generally with a good prognosis. Since CSCs detection by CD133 has been described as an important prognostic factor for several human cancers, we suggest the importance of detecting stem cell compartiments in all histotypes of breast carcinomas.