Karin Jirström is a professor and consultant in pathology. She has longstanding experience in tumour-agnostic cancer biomarker research, and her laboratory harbours a wide range of tissue microarrays with retrospectively collected, clinically well-annotated tumours representing several types of major solid cancers. She is now following up with prospective clinical on-treatment biomarker studies exploring the temporal heterogeneity and clonal evolution of tumours. The goal is to design better individualized and adaptive treatment strategies, thereby improving the outlook for patients with particularly hard-to-treat cancers.