Dual color chromogenic in situ hybridization for determination of HER2 status in breast cancer: a large comparative study to current state of the art fluorescence in situ hybridization

<p>Abstract</p> <p>Background</p> <p>Chromogenic in situ hybridization (CISH) is fast becoming a well established technique for easy and sensitive determination of HER2 gene status in breast cancer. However, for the chromogenic method to achieve status as a safe and reliable technique, the method needs to be validated against already known and validated FISH techniques.</p> <p>Methods</p> <p>Here it is reported from a comparative study where HER2 gene status obtained by <it>HER2 </it>CISH pharmDx™ Kit was compared to HER2 gene status obtained by the FDA approved <it>HER2 </it>FISH pharmDx™ Kit and the PathVysion HER-2 DNA probe Kit. The study included 365 formalin fixed and paraffin-embedded invasive breast cancer tissue specimens collected consecutively at a US reference laboratory.</p> <p>Results</p> <p>The data obtained revealed an overall HER2 status concordance of approximately 98% for comparisons of <it>HER2 </it>CISH pharmDx™ Kit to both <it>HER2 </it>FISH pharmDx™ Kit and PathVysion HER-2 DNA Probe Kit.</p> <p>Conclusions</p> <p>The concordance between results obtained using the recently FDA approved <it>HER2 </it>CISH pharmDx™ Kit with previously FDA approved FISH techniques for HER2 gene status determination indicate that the <it>HER2 </it>CISH pharmDx™ Kit is a reliable chromogenic alternative to fluorescence-based methods.</p