Fluorescence In Situ Hybridization for MicroRNA Detection in Archived Oral Cancer Tissues
Figure 2
Suppressing endogenous peroxidase is critical for TSA-based in situ hybridization. Residual peroxidase activity from endogenous sources leads to background staining and obscures the truly positive signals. Hydrogen peroxide (H2O2) and hydrochloric acid (HCl) solution were compared for effectiveness in suppression of endogenous peroxidase activity. (a, b) Incubation with high concentration (3%) H2O2 in PBS (instead of more commonly used 0.3% H2O2) for 10 minutes does not suppress endogenous peroxidase. (c, d) The suppression from 0.024 M hydrochloric acid in ethanol for 10 minutes is more extensive. Red: Cy5-tyramide showing existence of peroxidase activity, blue: 4′,6-diamidino-2-phenylindole (DAPI) stained nuclei. Original magnification 200x.
