Microfluidic processor allows rapid HER2 immunohistochemistry of breast carcinomas and significantly reduces ambiguous (2+) read-outs

Abstract

Biomarker analysis is playing an essential role in cancer diagnosis, prognosis, and prediction. Quantitative assessment of immunohistochemical biomarker expression on tumor tissues is of clinical relevance when deciding targeted treatments for cancer patients. Here, we report a microfluidic tissue processor that permits accurate quantification of the expression of biomarkers on tissue sections, enabled by the ultra-rapid and uniform fluidic exchange of the device. An important clinical biomarker for invasive breast cancer is human epidermal growth factor receptor 2 [(HER2), also known as neu], a transmembrane tyrosine kinase that connotes adverse prognostic information for the patients concerned and serves as a target for personalized treatment using the humanized antibody trastuzumab. Unfortunately, when using state-of-the-art methods, the intensity of an immunohistochemical signal is not proportional to the extent of biomarker expression, causing ambiguous outcomes. Using our device, we performed tests on 76 invasive breast carcinoma cases expressing various levels of HER2. We eliminated more than 90% of the ambiguous results (n = 27), correctly assigning cases to the amplification status as assessed by in situ hybridization controls, whereas the concordance for HER2-negative (n = 31) and -positive (n = 18) cases was 100%. Our results demonstrate the clinical potential of microfluidics for accurate biomarker expression analysis. We anticipate our technique will be a diagnostic tool that will provide better and more reliable data, onto which future treatment regimes can be based.

Antigen Masking During Fixation and Embedding, Dissected

“…However, a section affixed to a glass slide is very asymmetrical in terms of access and exchange of reagents, as demonstrated by the comparison of staining by free diffusion or forced microfluidic flow. 33 Another difference we noticed is that stressstripping, 15 a 2-hr, 60C FA-fixed frozen section, with or without AR, leads to destruction and loss of the tissue (not shown), while an FFPE is not modified. Thus, the whole process and most likely FA-induced bonds plus dehydration in the whole tissue introduce modifications which are only partially reversed by AR, with the double bonus of AR and tissue stabilization.…”

Lab-on-a-chip devices: How to close and plug the lab?

“…5b) [109], respectively. The bonding technique developed in this work was later used in the fabrication of a high-pressure compatible microfluidic chip for immunohistochemical applications [110].…”

Microfluidics: reframing biological enquiry

“…The precision of microfluidic devices has improved existing single-cell assays (such as immunocytochemistry 23 and immunohistochemistry 24,25 ) and has bolstered the invention of novel assays for quantitative analysis of thousands of cells with single-cell resolution 26 .…”