First comparison of a biomarker analysis by RT-qPCR (MammaTyper®) versus visual or computer-assisted immunohistochemistry (IHC) in subtyping mammary carcinomas
- Significantly more precise prediction of pathologically complete remission in a neoadjuvant setting with MammaTyper® compared to manual or computer-assisted IHC; better therapy stratification and possible avoidance of unnecessary therapies
- MammaTyper® provides reliable quantitative determination of MKI67-mRNA expression
BioNTech Diagnostics GmbH, a subsidiary of BioNTech AG, announces the publication of further study data which again document the superiority of the in-vitro diagnostic MammaTyper® test (CE marked IVD) over immunohistochemical detection methods (IHC) (1). "The special feature of the currently published performance evaluation study is the fact that, for the first time, results of gene expression analysis with MammaTyper® were not only compared with results of manual microscopic analysis of immunohistochemical specimens but also with computer-assisted image analysis", emphasized Dr. Sierk Pötting, Managing Director of BioNTech Diagnostics GmbH. The study used formalin-fixed, paraffin-embedded (FFPE) routine biopsy samples from breast cancer patients who had participated in a randomized neoadjuvant study (2). These samples were analyzed with the three methods prospectively and retrospectively. In the currently published study, as well as in previous publications (3,4), MammaTyper® demonstrated a significant superiority in the quantitative determination of the proliferation marker MKI67 (Ki-67) compared to IHC. Therefore MammaTyper® achieves significantly higher specificity than IHC in the identification of a possible pathological complete remission after neoadjuvant therapy. Prof. Dr. Hans-Peter Sinn, University of Heidelberg and head of the study summarized the results as follows: "The study demonstrates that MammaTyper® is able to reliably prognosticate tumor proliferation activity and the response to neoadjuvant therapy. That means patients may be spared unnecessary treatments".
The classification of tumors in luminal, basal and HER2-amplified subtypes by the immunohistochemical markers estrogen receptor (ER), progesterone receptor (PR), HER2 and the proliferation marker Ki-67 provides the basis of biological subtyping and (neo)adjuvant therapy decisions for mammary carcinomas (5). Moreover, since the 2013 St Gallen Conference, the proliferation marker Ki-67 has also been confirmed for the definition of the intrinsic subtypes Luminal A and Luminal B-like (6). An earlier study in a neoadjuvant setting was able to show that high Ki-67 values are consistently associated with higher rates of pathological complete remission (11). The current standard method for detection of the Ki-67 proliferation marker as well as the biomarkers ER and PR is manual microscopic immunohistochemistry which has, however, been debated for some time due to the great intra- and inter-observer variability (7,8).
Results of the determination of biomarkers ESR1 (ER) and PGR (PR) in the currently published study again confirm the good correlation of MammaTyper® with immunohistochemistry results, showing a slightly higher correlation of MammaTyper® and computer-assisted immunohistochemistry (ER/ESR1: 91.23 %, p<0.0001; PR/PGR: 92.9 %, p < 0.0001). In contrast, MammaTyper® and computer-assisted IHC image analysis achieved , as expected, moderate correlation (Spearman’s r = 0.5; p = 0.0001) in the detection of the proliferation marker MKI67 (Ki-67). However, correlated with clinical progress data, MammaTyper® proved to be significantly superior to IHC – especially in predicting the response to neoadjuvant therapy derived from MKI67 determination.
The current study shows again that MammaTyper® is an interesting and reliable alternative to the currently customary IHC detection methods. Moreover, MammaTyper® offers the possibility for an improved prediction of pathological complete remission after neoadjuvant chemotherapy.
Therefore, MammaTyper® could contribute to a well-founded therapy decision which could spare breast cancer patients unece...
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