Target Print (TP) is a microarray-based gene expression test which offers a quantitative assessment of the patient'slevel of estrogen receptor (ER), progesterone receptor (PR) and HER2/neu overexpression within her breast cancer. As compared to Immunohistochemistry (IHC), TP delivers an added benefit to the diagnostic process. IHC provide a semi-quantitative positive or negative result, whereas the gene expression result provided by TP allows to integrate the absolute level of ER, PR and HER2 gene expression into treatment planning. It is known that differences in tissue fixation, choice of antibody and interpretation can severely affect IHC accuracy and reproducibility.
