Figure 1

Immunoreactivity for neural stem/progenitor cell markers in cases of primary CNS lymphoma (NHL-CNS). A-C) are sections of 3 different cases of NHL-CNS immunostained for Musashi-1. There are rare immunopositive cells within the tumor or at the edges of the tumor in the adjacent gliotic brain. D-F) are sections of the same tumors immunostained for group II beta-tubulin. There is some background immunopositivity in the brain of neural processes, but cytoplasmic immunopositivity is seen in only in relatively rare cells along the edges of the tumors and, less frequently, within the tumors. G) Immunostain for nestin in a section from a case of NHL-CNS. There are some nestin-immunopositive cells along the border between the brain and the lymphoma, transgressing a short distance into the tumor between the lymphoma cells. H and I) Immunostains for CD133 in two cases of NHL-CNS. In (H) there are immunopositive cells in the brain between two portions of tumor; in (I) there are rare immunopositive cells within the tumor cell aggregates. For comparison to all of these, (J) is an immunostain for GFAP in one of these cases, demonstrating maximal gliosis along the border between the tumor and the brain with a few entrapped GFAP-immunopositive astrocytes among the tumor cells deeper into the neoplastic aggregate. All photomicrographs at original magnification of 400x.