A high proliferative index represented by Ki67 positivity favored a high-grade B-cell lymphoma with MYC, BCL2, and BCL6 rearrangement, possibly a double-expressor phenotype or a triple hit lymphoma if proven by classic cytogenetics, FISH, or other molecular or genetic tests. The gene discussed is MKI67; the disease is B-cell non-Hodgkin lymphoma.