CercaTestTM ERBB2 Assay is a quantitative real-time PCR assay for accurate measurement of ERBB2 gene expression in breast cancer tissue slices. Contiguous quantitative PCR cycle numbers may be generated from different FFPE tissue samples with the same IHC scores (such as HER2 0 or 1+), allowing delineation of different ERBB2 mRNA expression levels in full spectrum. The assay is run on commonly available PCR platforms, thus obviating the need for pathology readings and scorings and avoiding human subjectivity and errors.