The ERBB2/Cen17 DNA-FISH Probe is designed to detect the amplification of the ERBB2 gene (also named HER2/neu) on chromosome 17q12 relative to the control Cen17 using fluorescence in situ hybridization (FISH) in formalin-fixed, paraffin-embedded (FFPE) breast cancer tissues.  Overexpression of the ERBB2 gene occurs in 25-30% of human breast carcinomas, and ~90-95% of these cases result directly from gene amplification.^[1]  Patients showing such an amplification are at high-risk for relapse and lower overall survival.^[1-3]  Amplification of the ERBB2 gene predicts a favorable response to certain chemotherapy regimens and selective monoclonal antibody therapy with trastuzumab.^[1-5]  ERBB2 amplification is also seen in other solid tumors such as gastric, esophageal, gynecologic, bladder, and non-small cell lung cancer and correlates with a poor prognosis.^[6]