Comment on Parrilla Castellar et al, page 1473 What is a true ALCL?

In this issue of Blood, Parrilla Castellar et al present a large cohort of anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) in which they try to understand the diagnostic and the prognostic role of DUSP22 and TP63 in ALK-negative ALCL.1 ALCL is a mature aggressive T-celllymphoma. The definition of this disease has changed over the last decades. It was initially defined by the histomorphology of the lymphoma cells (anaplastic); the development of the CD30 antibody and its application in immunohistochemistry revealed that the morphological spectrum of the disease is much broader than anticipated.2 The discovery of ALK translocations and ALK expression in a subset of ALCL provided a very specific lymphoma marker. With the detection of AL