By analyzing SMARCB1 RNA and protein expression levels in multiple subtypes of mature T-cell lymphomas, we could exclude T-PLL, MEITL, EATL, MF, AITL and ALK-negative ALCL being the human counterpart of the phenotype observed in Smarcb1-deficient mice. The gene discussed is SMARCB1; the disease is anaplastic large cell lymphoma.