Table 3. Advantages and disadvantages of FISH and CISH.

FISH	CISH
Pro	Con
• Possibility of multicolour (HER2 and chromosome 17)	• No multicolour detection
• Is the simplest, without any chromogen detection	• Needs a chromogenic procedure
• Is currently the standard hybridisation procedure for HER2	• Not yet a standard hybridisation procedure for HER2
Con	Pro
• Requires a modern and expensive fluorescence microscope	• An ordinary microscope is effective
• FISH is not routinely used in pathology, and pathologists are not trained to analyse FISH signals	• Pathologists are familiar with IHC signals
• Fluorescence signals can fade within several weeks	• Chromogenic reaction is permanent
• Results have to be recorded with an expensive CCD camera	• Regular slide storage
• Morphology is not always easy to analyse	• Morphology is easier to analyse