The TERC FISH probe set is designed to measure the copy number of the human TERC gene located on chromosome band 3q26.2. The kit contains two differentially labeled probes: A Locus Specific Probe (LSP) covers the area of the TERC gene and adjacent chromosomal regions. The other probe, CCP 7, is derived from chromosome 7-specific alpha satellite DNA and is designed to serve as a control to determine the number of chromosome 7 copies per cell.