Epstein-Barr encoding region (EBER) in situ hybridization is the methodology of choice for the detection of the Epstein-Barr virus (EBV) in tissue sections. Because of the large numbers of copies of EBERs present in latently infected cells, non-isotopic methods can be used. Positive studies show staining in the nuclei of the EBV-infected cells, accentuating the chromatin and often excluding the nucleolus. False-negative results are most often the result of RNA degradation in the tissues, a finding that may be detected through the use of a polyT probe as a control for RNA preservation.