A biopsy of the right mammary gland tumor was performed, showing CD20 (+), CD21 (-), bcl-2 (+), CD10 (+), CD30(-), bcl-6 (+), MUM-1 (+), C-myc (70%+), CD19 (+), TDT (-), MPO (-), Ki-67 (+90%), MYC, and BLC2 rearrangements; a pathological diagnosis of high-grade, double-hit B-cell lymphoma was made. Here, MKI67 is linked to B-cell non-Hodgkin lymphoma.