AbstractThe increasing demand for personalized cancer therapy requires a strong, intense, and continuous collaboration between pre-clinical and clinical investigators. As a part of the EORTC Translational Research Divison, the EORTC PathoBiology Group (EORTC PBG), focuses on discovery and validation of cancer biomarkers, providing both scientific evidence as well as quality assurance. The clinically relevant target-identification and validation studies carried out in the last decades within the EORTC PBG represent a paradigm for EORTC studies in which laboratory investigations on human biologic material are used to support the development of drugs directed to defined target molecules. The experience acquired within the EORTC PBG with respect to standardization of cancer biomarker test kits and reagents, quality assessment/assurance of cancer biomarker determinations, development of standard operating procedures for assessment of these markers as well as instruction of methodologies and teaching of ethical issues represent a valuable contribution of the EORTC PBG to the onco-translational strategies of the EORTC.