Since the detection of ALK fusion protein in lymphocytes correlates perfectly with the presence of the ALK chromosomal fusion, immunohistochemistry (IHC) with specific anti-ALK monoclonal antibodies4,17 has displaced DNA molecular tests for the diagnosis of ALK-positive ALCL (FISH detection of ALK gene translocations is technically possible but labor- and time-consuming, and costly). Here, ALK is linked to anaplastic large cell lymphoma.