However, the following aggressive B-cell lymphomas are excluded from BCLu-DLBCL/BL: cases with typical DLBCL morphology with a very high proliferation index, typical DLBCL with a MYC translocation, and typical BL in which a MYC rearrangement cannot be demonstrated and those with IG-MYC rearrangement as the only abnormality, since they probably correspond to real BL with atypical morphology. The gene discussed is MYC; the disease is B-cell non-Hodgkin lymphoma.