C. B220 antibody immunostaining of the tumor section as shown in B. Neoplastic large and small cells uniformly interact with B220 antibody, confirming the B-cell origin of this tumor. D. Consistent with metastasis, RIZ1 mutant animals with the Peyer's patch DLL also commonly had enlarged mesenteric lymph nodes or whitish nodules in the spleen, liver, kidney, or lung. E. High power histopathology of the enlarged lymph node. F. B220 immunostaining of the enlarged lymph node. Normal reactive B cells are weakly stained.
Unstained cells are T cells and macrophages.
It is interesting to note that tumor cells reacted with B220 more strongly than did normal B cells, indicating increased expression of the CD45RB antigen in tumor cells.