A growing number of clinical trials incorporate invasive procedures like nondiagnostic tumor biopsies for biomarker or pharmacodynamic analysis.1 Such invasive research procedures are ethically contentious. Tumor biopsies involve pain and complication risk,2 and at least one procedure-related death has been reported.3 However, nondiagnostic tumor biopsies obtained in the research context generally have no value for managing the participant’s medical condition. Some commentators therefore argue that research biopsies “take” from participants without “giving in return.”4 Because such procedures are conducted contrary to research participants’ medical interests, an ethical framework for enrolling patients in studies that include a research biopsy rides heavily on informed consent. In particular, study participants should understand that research biopsies are nontherapeutic and burdensome and that participation is discretionary in studies involving them. Yet little is known about whether decisions to enroll in a study that involves a research biopsy, including those that permit participants to opt out of the procedure, meet thresholds of consent validity, in other words, whether individuals sufficiently understand and appreciate the consequences of their decision and whether they are not unduly influenced.5 Some studies about research biopsies suggest that individuals often misconstrue nondiagnostic biopsies as therapeutic; 6 others suggest the contrary.7 Interpreting these findings is further complicated by the fact that because participants were often enrolled in clinical drug trials, they might have legitimately imputed therapeutic value to research biopsies when receiving access to investigational drugs was conditioned on providing a biopsy for research.8 There are at least three reasons that clinical trials that include research biopsies might present challenges for consent validity. First, because procedures are burdensome, individuals who enroll in these trials might do so under the mistaken belief that the biopsies provide a therapeutic benefit to them. Second, biopsies are often conducted proximate to therapeutic encounters, where patients undergoing a biopsy might be focused on a recent diagnosis and on management options, not on their role as a research participant. Last, some argue that because research participants often conflate research with clinical care,9 they might fail to appreciate the nontherapeutic nature of a research biopsy. To investigate these issues, we used semistructured interviews to probe recalled perceptions, motivations, and consent quality for research participants in a cancer biomarker study involving nondiagnostic biopsies
