The NPM-ALK transgene can transform normal human CD4⁺peripheral T-cells into ALCL. (A) NPM-ALK–transduced normal CD4⁺ peripheral T cells become immortalized and acquire morphology and surface phenotype of ALCL, including expression of CD30, PD-L1, and IL-10, at least partial loss of the TCR, CD2, CD5, and CD5, and maintenance of CD4. (B) Histologic examination of the tumors formed by the NPM-ALK–transformed CD4⁺ T cells xenotransplanted into nonobese diabetic/severe combined immunodeficient γ mice reveals their striking and immunophenotypic resemblance to the primary, patient-derived ALK+ ALCL. H&E, hematoxylin and eosin.