PT  - JOURNAL ARTICLE
AU  - Scheffer, George L.
AU  - Maliepaard, Marc
AU  - Pijnenborg, Adriana C. L. M.
AU  - van Gastelen, Margôt A.
AU  - de Jong, Mariska C.
AU  - Schroeijers, Anouk B.
AU  - van der Kolk, Dorina M.
AU  - Allen, John D.
AU  - Ross, Douglas D.
AU  - van der Valk, Paul
AU  - Dalton, William S.
AU  - Schellens, Jan H. M.
AU  - Scheper, Rik J.
TI  - Breast Cancer Resistance Protein Is Localized at the Plasma Membrane in Mitoxantrone- and Topotecan-resistant Cell Lines
DP  - 2000 May 15
TA  - Cancer Research
PG  - 2589--2593
VI  - 60
IP  - 10
4099  - http://cancerres.aacrjournals.org/content/60/10/2589.short
4100  - http://cancerres.aacrjournals.org/content/60/10/2589.full
SO  - Cancer Res2000 May 15; 60
AB  - Tumor cells may display a multidrug resistant phenotype by overexpression of ATP-binding cassette transporters such as multidrug resistance (MDR1) P-glycoprotein, multidrug resistance protein 1 (MRP1), and breast cancer resistance protein (BCRP). The presence of BCRP has thus far been reported solely using mRNA data. In this study, we describe a BCRP-specific monoclonal antibody, BXP-34, obtained from mice, immunized with mitoxantrone-resistant, BCRP mRNA-positive MCF-7 MR human breast cancer cells. BCRP was detected in BCRP-transfected cells and in several mitoxantrone- and topotecan-selected tumor cell sublines. Pronounced staining of the cell membranes showed that the transporter is mainly present at the plasma membrane. In a panel of human tumors, including primary tumors as well as drug-treated breast cancer and acute myeloid leukemia samples, BCRP was low or undetectable. Extended studies will be required to analyze the possible contribution of BCRP to clinical multidrug resistance.