  What does it mean to explain cancer? The question is ambiguous, and fraught. For, by “cancer” one could have several targets of explanation in mind: the transformation of a cell into a “cancer cell,” the (general) process of carcinogenesis, the process of invasion and metastasis in solid tumors, the emergence and roles of intratumor heterogeneity, differential rates of incidence of different cancer types, patterns of cancer incidence or mortality in different environments, socioeconomic groups, races, ages, or sexes. Each of these explanatory targets arguably calls for quite different kinds of explanation and not only different explanatory information. Cancer scientists make appeals to generalizations of wide scope, for instance, and will also offer detailed, specific mechanistic explanations of specific outcomes. The fact that these explanations are different in kind may (in part) explain why there appears to be such a variety of views amongst philosophers concerning the aim and character of explanation and progress in cancer research. There is, of course, a long history of debate among philosophers of biology concerning norms of explanation. It’s still hotly debated whether, for instance, all explanations in the biological sciences must identify causes, or mechanisms, or whether “mathematical” or “equilibrium” explanations are distinct in kind, and how “network” models or “systems theoretical” explanations are distinct from other kinds of explanation, are all live debates (See the entries on   scientific explanation and   philosophy of systems and synthetic biology).  However, there is also a history of dispute amongst cancer scientists about both competing research agendas and explanatory strategies.