Next, we sought to characterize ALK protein expression in 55 human neuroblastoma tumors and in 43 normal pediatric tissues using immunohistochemistry (IHC) staining on tissue microarrays (TMAs) with the clinically validated and FDA approved D5F3 anti-ALK antibody, known to bind to the cytoplasmic kinase domain of ALK31,36. Here, ALK is linked to neuroblastoma.