Detection of RNA in FFPE tissue. Representative results of RNA detection in FFPE human tissue from an anonymous patient with Epstein-Barr Virus (EBV)-associated Hodgkin's lymphoma. EBER1 RNA should appear in the neoplastic Reed-Sternberg cells and not in the surrounding lymphocytes. The counterstain is DAPI, producing blue cell nuclei. (A) Detection of EBV-encoded early RNA (EBER)1 with a Turtle Probe (TP-EBER1-id33). (B) Detection of the same target on the same material with a Padlock Probe (PP-EBER1-id16). (C) Combined detection of EBER1 and hTR with the probes TP-EBER1-id33 (green) and TPhTR-id16 (red). The two probes were co-hybridized, co-amplified, and co-detected with a mixture of Lin16 (red identifier) and Lin33 (green identifier). (D-F) Negative controls identical to (B), save for the following: (D) pretreatment with RNase, (E) exclusion of the Turtle Probe, or (F) replacement of the correct probe with a non-complementary probe (the EBV1-id16 probe, which does not recognize EBER1, but rather the BamHI repeat of EBV). A 63× objective was used and scale bar is 50 μm.