Ethics can best be thought of as the moral principles that underpin good behavior. However, how this is defined is open to wide interpretation, and depends on factors such as societal norms and religion. Thales of Miletus (624 BC – 546 BC) advised his contemporaries to avoid doing what they would blame others for doing, and similar expressions of this concept abound throughout a range of moral philosophies. In medicine, the concept of non-maleficence (i.e., not harming the patient) is established as a pillar of physician behavior.

Due to the recent developments in the field of molecular diagnosis, it has become evident that there is no such entity as cancer per se, as there are considerable biological differences even within a particular anatomical subtype. Genomic characteristics do not only help to better define tumor subtypes, but frequently they provide the opportunity to target these subtypes as well.

In this special issue related to biomarkers and ethics in oncology trials, international experts have provided their perspectives on the most important elements related to their successful design, conduct and implementation of their results into clinical practice.  Dr. Silvia Novello and myself review how there has been a renewed optimism in achieving major improvements in the clinical care of patients based upon the identification and use of biomarkers that relate to the underlying biology of cancer.