1. What are misidentified cell lines? International Cell Line Authentication Committee ICLAC.org

2. Cell lines are grown in laboratories worldwide to help us understand how normal cells function and how disease happens. 2014 International Cell Line Authentication Committee.

3. HeLa was the first human cell line. Thousands of cell lines, from many different species and tissues, now exist in laboratories worldwide. 2014 International Cell Line Authentication Committee. HeLa cells in culture, magnified and fluorescently stained to highlight different cellular components

4. Every cell line has a story. The donor of that cell line and the scientists who established it are all part of that story. 2014 International Cell Line Authentication Committee.

5. For some cell lines, we lose track of the story. Misidentified cell lines no longer correspond to the original donor and may come from an entirely different species, tissue or disease. 2014 International Cell Line Authentication Committee.

6. Cell lines become misidentified through cross-contamination, mislabelling, or other laboratory errors. The problem was uncovered by Stanley Gartler and Walter Nelson-Rees in the 1960s and 1970s. 2014 International Cell Line Authentication Committee.

7. Chang liver More than 400 misidentified cell lines are now known. Using these cell lines – without knowing their true story – results in chaos and confusion in the scientific literature. HEK HES KB MT-1 BG-1 HEp-2 WiDR ECC-1 2014 International Cell Line Authentication Committee. Source: iclac.org/databases/cross-contaminations/. WISH DAMI MDA-MB-435 Intestine 407 SNB-19 Detroit-6

8. The International Cell Line Authentication Committee (ICLAC) is a voluntary group of scientists that works to increase awareness of misidentified cell lines. 2014 International Cell Line Authentication Committee.

9. ICLAC curates a database of known misidentified cell lines. Scientists should check the database before they start work with a new cell line, to see if that cell line is known to be misidentified. Originally thought to be: Human, normal liver Now known to be: HeLa cell line Human, cervical cancer References: Lavappa et al, 1976; Nelson-Rees et al, 1981 2014 International Cell Line Authentication Committee. Source: iclac.org/databases/cross-contaminations/. Chang liver

10. Misidentified cell lines can be detected by authentication testing. Scientists should test their cell lines using an accepted consensus method, such as short tandem repeat (STR) profiling. Mixed Culture (early cross-contamination) Contaminating cells in culture STR profile shows mixture 2014 International Cell Line Authentication Committee. Images: CellBank Australia, used by permission.

11. Characterization and maintenance of essential characteristics Quality Assurance Recording Reporting Safety Education and Training Ethics 2014 International Cell Line Authentication Committee. Good Cell Culture Practice principles: Hartung T, Zurlo J (2012) ALTEX 29(3): 251-60. Good Cell Culture Practice – including authentication testing – is essential if cell lines are to be good models for health and disease. 2014 International Cell Line Authentication Committee. Good Cell Culture Practice principles: Hartung T, Zurlo J (2012) ALTEX 29: 251-60.

12. Every cell line has a story. That story is important if we are to make research using cell lines more reliable and reproducible. What story does your sample tell? 2014 International Cell Line Authentication Committee.

13. International Cell Line Authentication Committee To reduce the impact of misidentified cell lines: 1.Check our list of misidentified cell lines before you start work http://iclac.org/databases/cross-contaminations/ http://iclac.org/databases/cross-contaminations/

14. International Cell Line Authentication Committee To reduce the impact of misidentified cell lines: 1.Check our list of misidentified cell lines before you start work http://iclac.org/databases/cross-contaminations/ http://iclac.org/databases/cross-contaminations/ 2.Incorporate authentication testing into everyday culture practice http://iclac.org/resources/advice-scientists/ http://iclac.org/resources/advice-scientists/

15. International Cell Line Authentication Committee To reduce the impact of misidentified cell lines: 1.Check our list of misidentified cell lines before you start work http://iclac.org/databases/cross-contaminations/ http://iclac.org/databases/cross-contaminations/ 2.Incorporate authentication testing into everyday culture practice http://iclac.org/resources/advice-scientists/ http://iclac.org/resources/advice-scientists/ 3.Report testing as an essential part of publications and grant applications http://iclac.org/resources/cell-line-checklist/ http://iclac.org/resources/cell-line-checklist/