Open Access Highly Accessed Research article

Molecular and cellular characterization of ABCG2 in the prostate

Laura E Pascal12*, Asa J Oudes12, Timothy W Petersen2, Young Ah Goo12, Laura S Walashek12, Lawrence D True3 and Alvin Y Liu12

Author Affiliations

1 Department of Urology, and the Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle WA 98195, USA

2 Institute for Systems Biology, Seattle WA 98103, USA

3 Department of Pathology, University of Washington, Seattle, WA 98195, USA

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BMC Urology 2007, 7:6  doi:10.1186/1471-2490-7-6

Published: 10 April 2007



Identification and characterization of the prostate stem cell is important for understanding normal prostate development and carcinogenesis. The flow cytometry-based side population (SP) technique has been developed to isolate putative adult stem cells in several human tissue types including the prostate. This phenotype is mainly mediated by the ATP-binding cassette membrane transporter ABCG2.


Immunolocalization of ABCG2 was performed on normal prostate tissue obtained from radical prostatectomies. Normal human prostate SP cells and ABCG2+ cells were isolated and gene expression was determined with DNA array analysis and RT-PCR. Endothelial cells were removed by pre-sorting with CD31.


ABCG2 positive cells were localized to the prostate basal epithelium and endothelium. ABCG2+ cells in the basal epithelium constituted less than 1% of the total basal cell population. SP cells constituted 0.5–3% of the total epithelial fraction. The SP transcriptome was essentially the same as ABCG2+ and both populations expressed genes indicative of a stem cell phenotype, however, the cells also expressed many genes in common with endothelial cells.


These results provide gene expression profiles for the prostate SP and ABCG2+ cells that will be critical for studying normal development and carcinogenesis, in particular as related to the cancer stem cell concept.