The kit uses fluorescence in situ hybridization (FISH) technology, which employs a dual-color HER-2/CSP17 FISH probe with two fluorescent-labeled DNA probes to detect HER-2 gene amplification and over-expression.The tissue specimens were handled with a series of pre-treatment procedures, and the targeted DNA is denatured to single-stranded form and hybridized with the FISH probes.