High prevalence of side population in human cancer cell lines

Maximilian Boesch1,2, Alain G. Zeimet3, Heidi Fiegl3, Barbara Wolf3, Julia Huber2, Helmut Klocker4, Guenther Gastl2, Sieghart Sopper2,*, Dominik Wolf5,*

1 Institute of Immunobiology, Kantonsspital St. Gallen, 9007 St. Gallen, Switzerland

2 Internal Medicine V, Medical University of Innsbruck, 6020 Innsbruck, Austria

3 Department of Gynecology and Obstetrics, Medical University of Innsbruck, 6020 Innsbruck, Austria

4 Department of Urology, Medical University of Innsbruck, 6020 Innsbruck, Austria

5 Medical Clinic III, University Clinic Bonn (UKB), 53127 Bonn, Germany

* These authors contributed equally to this work.


Maximilian Boesch, email:

Keywords: side population, cancer cell line, stem cell, drug resistance, drug transporter

Received: March 15, 2016 Accepted: April 01, 2016 Published: April 10, 2016


Cancer cell lines are essential platforms for performing cancer research on human cells. We here demonstrate that, across tumor entities, human cancer cell lines harbor minority populations of putative stem-like cells, molecularly defined by dye extrusion resulting in the side population phenotype. These findings establish a heterogeneous nature of human cancer cell lines and argue for their stem cell origin. This should be considered when interpreting research involving these model systems.

PII: 300