NTRK1 and anaplastic large cell lymphoma: Anaplastic large-cell lymphoma is a pleomorphic large cell lymphoma with strong expression of the activation antigen CD30 (Ki1) in virtually every cell and frequent involvement of lymph node sinuses.95 Anaplastic large-cell lymphoma occurs predominantly in children and young adults, but a second peak incidence is seen in 60–80-year-olds.96 In 40–80% of anaplastic large-cell lymphomas, dysregulation of the receptor tyrosine kinase gene ALK97 on chromosome 2p23 is important in its pathogenesis.