The BRCA1/CCP17 FISH probe set is designed to detect copy number changes in the region of the human BRCA1 gene located on chromosome band 17q21.31. The kit contains two differentially labeled probes: A Locus Specific Probe (LSP) covers a chromosomal region which includes the entire BRCA1 gene. The other probe, CCP 17, is derived from chromosome 17-specific alpha satellite DNA and is designed to serve as a control to determine the number of chromosome 17 copies per cell.

The probe is labeled with CytoOrange and CytoGreen. CytoOrange is a fluorophore with an excitation peak at 551 nm and emission peak at 575 nm, giving it an orange fluorescent signal with an appropriate filter; CytoGreen has an excitation peak at 495 nm and emission peak at 518 nm, giving it an green fluorescent signal with an appropriate filter.