Solid lymphoma established in Nod/SCID mouse after iv injection with HBL-6 cells. (A) EBER ISH showing intense localization of signal (black chromagen) in nuclei of tumor cells indicating coinfection by EBV (60× magnification). (B) Polyclonal rabbit antiserum against KSHV vIL-6. A minority of cells express detectable protein (red chromagen), which is restricted to the cytoplasmic compartment (with exclusion of nuclei). (60× magnification; Mayer's hematoxylin counterstain). (C) EMA is strongly expressed in anaplastic tumor cells characterized by large pleomorphic nuclei and abundant mitotic activity (60× magnification; Mayer's hematoxylin counterstain). (D) Leukocyte common antigen (LCA) is not generally expressed in tumor cells consistent with the null immunophenotype association with PEL and derived cell lines (60× magnification; Mayer's hematoxylin counterstain).