Fig. 4

Left: Epstein-Barr virus-encoded small RNA (EBER) in situ hybridization of thyroid Burkitt’s lymphoma. The tumor cells are negative for Epstein-Barr virus (EBV) (×200). Right: EBER in situ hybridization of nasopharyngeal carcinoma, which was used as external positive control. The tumor cells are positive for EBV (× 200)