Immunostaining of progressively transformed germinal centers for Ki67 and Ki67/CD38.

(A,B) PTGCs of patients 3 and 5 stained for Ki67 using peroxidase to detect binding. (C) Ki67 and CD38 double staining of a PTGC of patient 5. Ki67 was visualized using peroxidase and DAB as substrate (brown) and CD38 with alkaline phosphatase and Fast Red. (D) High-power magnification of panel C (40 ×).