To comprehensively assess the expression of ALK in a representative cohort of primary prostate cancers, we performed IHC staining for ALK on TMAs of radical prostatectomy specimens from two academic centers (The Johns Hopkins School of Medicine and University of Washington) using a clinical grade and extensively validated ALK antibody (clone D5F3; ref. 28; Supplementary Fig. S1A). Here, ALK is linked to prostate cancer.