  The larger concern cases like this raise is whether there is one way to privilege choice of causal basis for classifying diseases like cancer. Different choice of temporal or spatial scale, or more or less fine-grained characterization of causal processes, might yield multiple, overlapping disease classifications.  While some may be willing to bite this bullet, and indeed, endorse pluralism and non-hierarchical classifications (see, e.g., Khalidi 1998, 2013), others might be concerned that this would yield too permissive an array of disease types. More generally, whether and how scientific researchers and clinicians are likely to to converge on a common classification for cancer raises some interesting puzzles about the aims and methods of classification in the biomedical sciences more generally. That genomic features of cancer are unlikely to unproblematically yield a natural taxonomy suggests that a reductive picture of disease classification is more generally implausible.  It seems that classifications of disease like cancer form a kind of ‘hybrid’—they are intended to capture natural regularities and their causes, but also to be of use for a wide array of agents with different purposes. It’s unclear whether all these purposes can be served by one univocal method or set of classificatory criteria.