ALCL is defined by expression of the CD30 marker of activated B and T cells and, in some cases, T cell markers such as CD4 or CD8, as well as production of cytotoxic molecules such as perforin, which together with the presence of clonal T-cell receptor (TCR) rearrangements, suggests an activated T-cell origin2, 3, 4, 5, 6. The gene discussed is PRF1; the disease is anaplastic large cell lymphoma.