The N1 subtype (2% of DLBCL) mostly contains ABC DLBCL with Notch activation (NOTCH1 mutations), NF-κB pathway (TNFAIP3 mutations or deletions), and impaired terminal B cell (lesions of IRF4, ID3, and BCOR). The gene discussed is BCOR; the disease is diffuse large B-cell lymphoma.