A number of authoritative reviews devoted to the role of the tumor microenvironment have been published in recent years [1], [2]. It is evident that the tumor stroma can modulate many tumor characteristics including the response to therapy. We need to keep this in mind, especially now that there is an increasing tendency to base intervention strategies on the driver mutations present in the tumor cells. This diagnostic mutation analysis receives attention for a good reason: it allows stratification of patients on the basis of molecular parameters with predictive power. Furthermore, the complexity of tumor cell populations is already challenging enough given the presence of a multitude of different cell types and their genetic heterogeneity. The contribution of stromal cells to a tumor tissue, including deposited matrices [3], can greatly vary, sometimes making up more than 90% of the tumor mass, for example as …