To identify potential cancers as early as possible specific screening procedures are available and promoted through screening programs such as:
• Breast Physical Examination
• Breast Self-Examination
• CT Scans (Computerized Tomography)
• Chest X-Rays
Further diagnostic testing of tissue biopsies is necessary to establish the pathological stage, the histologic type, the histologic tumor grade and the molecular subtype of the tumor. Biomarkers are used to distinguish different molecular subtypes of breast cancer.
Information on the molecular subtype is used by oncologists to assess individual prognosis of the patient and helps to select the best-suited therapy. The following are the most commonly used tests for determining the status of biomarkers and thus the molecular subtype of the tumor:
• IHC (Immunohistochemistry): Antibody staining of protein in tissue sections shows the expression of biomarkers on protein level. Pathologists visually assess the degree of staining and report a semi-quantitative score which is used to determine whether a biomarker is positive (above threshold) or negative (below threshold value). This approach is semi-quantitative by nature.
• FISH (Fluorescence in situ hybridization) or CISH (Chromogenic in situ hybridization) measure aberrant gene amplification in tumor cells and are typically conducted as a secondary method if the IHC shows intermediate/unclear results for the HER2 biomarker.
• RT-qPCR (reverse transcription quantitative real time PCR), determines actual gene expression of biomarkers on an mRNA level. This new generation of test delivers quantitative results, shows a much higher resolution and a broader dynamic range compared to IHC and eliminates several causes of variability that affect IHC measurements (MammaTyper® is based on RT-qPCR technique).