This article explores the ethical challenges following the use of genetic information in experimental cancer treatment. In Danish healthcare, current ethical debates on the wider use of genetic information are highly focused on the heredity of genetic information. This focus accords with the international bioethical literature and the established practices of assessing inherited risks for cancer. Drawing on Pols' (2003. "Enforcing Rights or Improving Care? The Interference of two Modes of Doing Good in Mental Health Care."Sociology of Health & Illness25 (4): 320-347. doi:10.1111/1467-9566.00349) concept ofmodes of doing good, we show that this has led to a certain understanding of the ethical challenges regarding genetic information - an understanding we term thegermline mode. We argue that the germline mode overlooks crucial dilemmas facing healthcare professionals who use genetic information to target treatment directly at patients' somatic mutations, i.e. alterations in the DNA occurring only in the tumor. In this article, we develop the concept of thesomatic modeand explore the ethical challenges that emerge when genetic information takes a somatic turn.