For both methods, paraffin tissue sections are cut on a microtome at 5 microns and placed onto silanized slides. Slides are allowed to air dry, preferably overnight. Cut sections should not be stored for more than 6 weeks before testing. A minimum of 4 hours drying time is required. Bake all slides overnight at 56°C before staining for FISH.
Unlike the hematoxylin and eosin (H&E) method, slides should be marked for the tumor area of interest on the underside of the slide using a diamond-tipped pen before beginning. This will ensure enough tumor cells are on the slide before the assay.
