The detection can be achieved by using a combination of ultraView SISH(silver in-situ hybridization) and ultraView Red ISH for deposition of distinct chromgenic precipitates at the site of DNP or DIG labeled probes.The recommended assays are a combination of IHC and FISH, whereby IHC scores of 0 and 1+ are negative (no trastuzumab treatment), scores of 3+ are positive (trastuzumab treatment), and score of 2+ (equivocal case) is referred to FISH for a definitive treatment decision. Industry best practices indicate the use of FDA-cleared Automated Tissue Image Systems by laboratories for automated processing of specimens, thereby reducing process variability, avoiding equivocal cases, and ensuring maximum efficacy of trastuzumab therapy. Resistance
One of the challenges in the treatment of breast cancer patients  by herceptin is our understanding towards herceptin resistance. In the last decade, several assays have been performed to understand the mechanism of Herceptin resistance with/without supplementary drugs. Recently, all this information has been collected and compiled in form of a database HerceptinR. This database HerceptinR is a collection of assays performed to test sensitivity or resistance of Herceptin Antibodies towards breast cancer cell lines. This database provides comprehensive information about experimental data perform to understanding factors behind herceptin resistance as well as assays performed for improving Herceptin sensitivity with the help of supplementary drugs. This is the first database developed to understand herceptin resistance that can be used for designing herceptin sensitive biomarkers.
Consequently, some countries with a taxpayer-funded public health system, such as New Zealand, chose to fund limited adjuvant therapy. However, subsequently New Zealand has revised its policy and now funds trastuzumab treatment for up to 12 months. Adverse effects
Some of the common side effects of trastuzumab are flu-like symptoms (such as fever, chills and mild pain), nausea and diarrhea. Cardiac toxicity
One of the more serious complications of trastuzumab is its effect on the heart, although this is rare. In 2-7% of cases, trastuzumab is associated with cardiac dysfunction, which includes congestive heart failure. As a result, regular cardiac screening with either a MUGA scan or echocardiography is commonly undertaken during the trastuzumab treatment period. The decline in ejection fraction appears to be reversible.Trastuzumab downregulates neuregulin-1 (NRG-1), which is essential for the activation of cell survival pathways in cardiomyocytes and the maintenance of cardiac function. NRG-1 activates the MAPK pathway and the PI3K/AKT pathway as well as focal adhesion kinases (FAK). These are all significant for the function and structure of cardiomyocytes. Trastuzumab can therefore lead to cardiac dysfunction.Approximately 10% of people are unable to tolerate the drug because of pre-existing heart problems; physicians are balancing the risk of recurrent cancer against the higher risk of death due to cardiac disease in this population. The risk of cardiomyopathy is increased when trastuzumab is combined with anthracycline chemotherapy (which itself is associated with cardiac toxicity).