We also evaluated our xenografts for evidence of EBV infection by ISH or polymerase chain reaction (PCR) for EBV-encoded RNA (EBER1) and found that the human-derived lymphoid tumors were EBER1 positive; however, no signal could be detected in the CD45− xenografts (Fig. 2A,B). The gene discussed is PTPRC; the disease is lymphoid neoplasm.