Wild Type and Mutated BRCA – Differentiation of Breast Cancer using New miRNA Biomarker Panel

Ready-to-Use fully optimized SSNA miRNA In Situ Hybridization (ISH) Kit

Breast cancer represents a heterogeneous group of tumors characterized by a wide range of clinical, pathologic and molecular features. Genetic susceptibility to breast cancer is highly increased with mutations in breast cancer susceptibility genes (BRCA1 and BRCA2). BRCA mutated breast carcinomas are commonly seen in younger patients and have a more aggressive clinical course. Identifying genomic biomarkers for breast cancer prognosis will lead to a better understanding of breast cancer genetics and a more accurate understanding of tumor behavior. Utilizing microRNAs (miRNAs) as a potential biomarker to differentiate BRCA will allow for specialized treatment regimens and increased clinical care.

miRNAs are small, evolutionarily conserved, noncoding RNAs that negatively regulate gene expression and have fundamental roles in cancer growth and metastasis. miRNAs exert their function via base pairing with complementary mRNA molecules, resulting in gene silencing via transcriptional repression or target degradation. Owing to their stability in biological fluids and resistance to various storage conditions, miRNAs are considered as useful biomarkers for cancer diagnosis, prognosis, and prediction of treatment efficacy. Dysregulation of miRNA has been widely reported in many cancer types, including breast cancer. Recent studies have tested miRNAs as predictive biomarkers for determining BRCA mutated patient’s prognosis. Although numerous methods are available for gaining information about miRNA signatures, in situ hybridization (ISH) assay is a powerful tool that allows direct assessment of malignant cells. Unlike PCR based techniques, ISH system has the ability to generate a robust chromogenic signal while preserving the spatial context of the tissue sample thus allowing precise tumor characterization.

Super Sensitive Nucleic Acid (SSNA) miRNA probes:

BioGenex has developed proprietary Super Sensitive Nucleic Acid (SSNA) miRNA probes that enhance signals from intrinsically low populated miRNAs. The SSNA oligos are synthesized using specially designed bases to give super high melting temperatures. The high melting temperatures enable stringent washes at elevated temperatures to remove non-specific binding. BioGenex miRNA probes are dual-end labeled on 3’ and 5’ with five FAM molecules that amplify the signal, giving intense stains. The high-density fluorophore-labeled SSNA probes combined with the BioGenex Super Sensitive ™ Detection System aid in studying the lowly expressed miRNA populations and miRNA expression profiles to assess the physiological function of miRNA.

The miRNA expression profiles are used to assess the cancer type or conditions for the below types:

1. Cancer of unknown primary
2. Undifferentiated and poorly differentiated tumors
3. Classification of cancer subtypes
4. Grading and staging of cancer

BioGenex is pleased to launch two Super Sensitive^TM Nucleic Acid miRNA in situ hybridization (SSNA miRNA ISH) probes and automated systems for differentiation of wild type and BRCA mutated breast cancer. BioGenex unique SSNA miRNA ISH probes enable detection of single nucleotide mismatch thus allowing high sensitivity and specificity with a clean intense staining. BioGenex miRNA ISH Panel Probes are currently one of the best products for complex diagnostic assays. Over 240 ready-to-use (RTU) miRNA probes are now available, and more are being developed. BioGenex SSNA miRNA probes combined with the automated processing using Xmatrx® greatly increases the reliability of the test results through the elimination of error-prone ISH procedure. BioGenex fully-automated molecular pathology workstations are the most advanced system globally.

Using BioGenex ISH miRNA probes, the expression pattern of distinct miRNAs were successfully differentiated in wild type and BRCA mutated breast carcinomas. The miRNA expression profile was evaluated in formalin-fixed paraffin-embedded (FFPE) invasive ductal carcinoma cases containing BRCA mutated and wild type breast carcinomas (1). Differential expression of miRNA was documented using the BioGenex Xmatrx® automated system and miRNA ISH BRCA breast panel probes. The in situ experimental conditions for hybridization were optimized for both manual and automated systems. As compared with wild type breast cancer, expression of miR-17 and miR-21 was downregulated in BRCA mutated breast cancer, suggesting that the miRNA expression pattern may serve as a potential biomarker in predicting BRCA mutation status in invasive breast cancer. miR-17 has been linked to tumorigenesis in a broad range of cancers, including gastric cancer (2), and colon cancer (3). In a recent study, miR-17 has been shown to play a significant role in breast cancer progression (4). Several studies have also reported miR-21 as a potential novel diagnostic biomarker for breast cancer (5, 6). A study by Wang et al suggests that circulating miR-21 could serve as a potential serum-based biomarker for breast cancer detection in the Chinese population, with 80.0% sensitivity and 87.7% specificity (6). Thus, understanding the relationship of the miRNA expression level to the BRCA mutation status can help develop effective targeted interventions and specialized treatment options.

Please click on above links to download Biomarker Panel and Application Note for Differentiation of Wild Type and Breast Cancer Susceptibility Gene (BRCA) Mutated Breast Cancer.

BioGenex also has an extensive catalog of over 240 unique miRNA probes

References:

1. Mohanty SK et al. miRNA Expression Pattern in Predicting BRCA Mutation Status in Invasive Breast Carcinoma. Presented as Poster in Annual Meeting of the United States & Canadian Academy of Pathology (USCAP) 2014.
2. Zhang X et al. F-box protein FBXO31 is down regulated in gastric cancer and negatively regulated by miR-17 and miR-20a. Oncotarget. 2014;5:6178-90.
3. Knudsen KN et al. microRNA-17 is the most up-regulated member of the mir-17-92 cluster during early colon cancer evolution. PLoS One. 2015;10:e0140503.
4. Yang F et al. miR-17 as a diagnostic biomarker regulates cell proliferation in breast cancer. OncoTargets Ther. 2017 ;10:543-50.
5. Gao Y et al. MicroRNA-21 as a potential diagnostic biomarker for breast cancer patients: a pooled analysis of individual studies. Oncotarget. 2016;7:34498-506.
6. Wang B, Zhang Q. The expression and clinical significance of circulating microRNA-21 in serum of five solid tumors. J Cancer Res Clin Oncol. 2012;138:1659-66.