Keith Kerr, MB, ChB, FRCPath, FRCPE from the University of Aberdeen, Aberdeen, Scotland, discusses testing novel biomarkers for treatment at the European Cancer Congress of the European Cancer Organisation (ECCO) 2017 in Amsterdam, Netherlands. He explains that it is the availability of drugs that drives the testing of new biomarkers. However, biomarkers can sometimes take a long time to validate. This can lead to biomarker testing techniques being developed before the drugs have been approved. The disadvantage of doing this, however, is not knowing whether the drug will pass its Phase III trials and be approved.