Levels of IL-9, IL-10, IL-17a, HGF, soluble IL-2R, and soluble CD30 collectively create a distinct cytokine profile specific to ALK+ ALCL, distinguishing them from both remission samples and samples from children of similar age with low-stage B-cell non-Hodgkin lymphoma, serving as special control groups. This evidence concerns the gene IL9 and anaplastic large cell lymphoma.