Although fluorescence in situ hybridization (FISH) technology is adequate, demand exists for additional recycling and long-term storage of FISH slides.
Formalin-fixed paraffin-embedded slides derived from breast cancer cases were used for this study. Each slide was probed, and then procedures for removing probes were performed, such as removing the fluorescent probe and diamidino-2-phenylindole signals. Formamide was used for removing probes, and then slides were stored dry at room temperature (22°C), 4°C, -20°C, or -80°C for 101 days. Following storage, each slide was probed in a similar manner to the initial probing. Evaluation was performed using automatic signal count software. Tiles and spots were counted immediately after the initial probing. Reprobed spots for each slide were then compared with the initial probing.
Slides stored at -20°C and -80°C for 101 days showed the best recovery of probing.
Our approach for probe removal and recycling allows repeated examination of even a limited number of slides.