In 2010, we published a seminal study in The New England Journal of Medicine about the role of tumor-associated microphages in classical Hodgkin lymphoma. In this study, we have found for the first time a significant correlation of CD68+ cells with progression-free and overall survival. In subsequent studies including the EA2496 Intergroup trial, we have reproduced these results and could show that specifically a subset of tumor-associated macrophages, CD163+ macrophages, are correlated with progression-free and overall survival. Other groups have also validated the prognostic impact of macrophages in general and specific subsets. Again, in our NanoString study, we see a very prominent macrophage signature in the 23 genes that have been selected for the model, validating the previous findings of our group and others.