think we are beginning to understand that
the same tumor in two different individuals
may not behave the same way. For certain
JAK2 [Janus kinase 2] mutations, for example,
particular germline polymorphisms
predispose for specific mutations. Then we
see epigenetic heterogeneity. This can be
associated with differentiation states, either
stem cell–like or more differentiated properties,
but also it might not necessarily be
differentiation‑related—for example, in cells
that acquire the ability to be drug resistant.
And then there is a phenotypic heterogeneity.
And that’s all just within one tumor. If
you’re talking about heterogeneity within
a patient, then you can add the metastatic
lesions as well.