PI9 is expressed in high-grade B-cell NHLs and some cases of Hodgkin lymphoma.

The following tumors were stained for PI9: diffuse large B-cell lymphoma (A), follicular B-cell NHL (B), B-CLL (C), and classical Hodgkin disease, nodular sclerosing subtype (D). Tissue sections were stained with mAb PI9-17 as described in “Patients, materials, and methods” and counterstained with hematoxylin. The arrowheads in panels B and C denote PI9⁺ dendritic cells, which served as a positive internal control for staining. Original magnification × 1000 for panels A and D; × 400 for panels B and C.