The MammaTyper® kit is an in vitro diagnostic test for the quantitative detection of mRNA expression of breast cancer biomarkers. Human epidermal growth factor receptor 2 HER2 (ERBB2), estrogen receptor (ESR1), progesterone receptor (PGR), and marker of proliferation Ki-67 (MKI67) can be measured with this kit. Additionally, the genetic test is intended for molecular subtyping into Luminal A-like, Luminal B-like (HER2 positive), Luminal B-like (HER2 negative), HER2 positive (non-luminal) and Triple negative (ductal) tumors.
The test result is furthermore prognostic for a patient’s risk of developing distant metastases and overall survival.
A therapy decision is based on the tumor subtype. The subtype is defined by presence or absence of over-/expression of certain target genes. Since some therapies are aiming at these specific targets (e.g. hormone receptors, HER2), a prerequisite for therapy response is the presence of these targets in the tumor and precise determination of target expression. MammaTyper® is an in vitro diagnostic test which is very suitable to accomplish that purpose.
In total the RNA expression of four biomarkers is measured via RT-qPCR using hydrolysis probes (FAM, JOE labeled). For the purpose of normalization the expression of two additional genes with non-varying expression, so called reference genes, is measured: The four disease-relevant biomarkers are ERBB2, ESR1, PGR, and MKI67, the two references genes are B2M and CALM2. The kit size allows the analysis of a maximum of 8 patient samples in triplicates together with a positive and a negative control in one run. A maximum of two runs (10 determinations in total) is possible with one kit.
The MammaTyper® test is appropriate for female patients, diagnosed with invasive breast cancer only. The test can be used for primary diagnostics of FFPE core needle biopsies as well as for characterization of resection specimens. It was not validated in men, in pregnant women and in patients with mucinous, papillary, medullary or tubular type of breast cancer, when no metastases are present in the ipsilateral axillary lymph nodes.
The MammaTyper® kit was developed and validated using total RNA extracted from formalin-fixed, paraffin-embedded (FFPE) breast cancer tissue samples. It is recommended to use the RNXtract® RNA extraction kit for pre-analytic processing of the FFPE material although other RNA extraction kits have been validated according to the MammaTyper® instructions for use. Eluates from the RNXtract® kit can directly be used in RNA specific RT-qPCR reactions.
The MammaTyper® kit was validated on the following instruments: Versant® kPCR cycler, LightCycler® 480 Instrument II, cobas z 480 Analyzer and ABI 7500 Fast. As described in the instructions for use, some additional small appliances and a plate centrifuge are necessary to perform the test.
The analysis can be performed in every molecular pathology laboratory. To avoid contamination with PCR products, separated areas for RNA isolation, RT-qPCR preparation and measurement are recommended (pre- and post-PCR). Interpretation of the test results may only be made by a physician in combination with other clinico-pathological factors. The patient’s clinical history and any additional diagnostic test results that have been generated should be included in decision making with regard to therapy.
One 10 µm FFPE tissue section is needed. Tumor cell content of the breast cancer tissue sample has to be at least 20 % as determined by a pathologist.
The MammaTyper® kit is based on one-step reverse transcription quantitative real-time PCR (RT-qPCR), allowing the quantitative and highly reproducible measurement of RNA expression of four biomarker genes: ERBB2, ESR1, PGR, and MKI67. RNA expression is calculated using a relative quantification method (ΔΔCq) using two reference genes (B2M, CALM) for normalization.
RNA isolation and MammaTyper® test can be performed within one day.
MammaTyper® is a precise and reproducible test for the quantitative determination of quantitative RNA expression of the four breast cancer biomarkers ERBB2, ESR1, PGR and MKI67 and overcomes inter-operator/observer variability known from other methods like immunohistochemistry. It can be performed in one day from sample to result. MammaTyper® is applicable for local testing in molecular pathology and/or routine IVD laboratories. It is currently the only test available that gives
With MammaTyper® a reliable and accurate tumor classification into the five subtypes Luminal A-like, Luminal B-like (HER2 positive), Luminal B-like (HER2 negative), HER2 positive (non-luminal) and Triple negative (ductal) is possible.