How should tissue samples be stored prior to performing PETS FISH?
Only tissues preserved in 10% Neutral Buffered Formalin (NBF) and subsequently paraffin embedded or previously paraffin embedded sections are suitable for use. NBF is most commonly used to preserve tissues and should be used for no longer than 3 months and then discarded. Extended formalin fixation time can cause major difficulties in PETS FISH such as reduced probe penetration, high levels of tissue auto-fluorescence, cell overlap or truncated nuclei and low hybridisation efficiency. Specimens should be fixed for between 18-24h in NBF, tissues fixed for longer will require Pepsin digestion times to be increased.
