Molecular profiling of breast cancer intra-tumor heterogeneity for the development of novel biomarkers

Abstract

Tumor heterogeneity often challenges cancer diagnosis. In addition, a lack of fresh frozen tissue specimens and nucleic acid degradation in archival tissue can negatively impact cancer diagnostics. However, as tumor heterogeneity is a known mechanism for the development of drug resistance, it is essential to characterize heterogeneous tumor tissue. Moreover, the quantitative measurement of biomarkers in archival material is useful in oncology research with access to libraries of clinically annotated material, in which retrospective studies can validate potential biomarkers and their clinical outcome correlation. In this study, our research team optimized quantification of RNA in archival material. The gene expression assay described in this manuscript is a novel, quick, and multiplex method that can accurately classify breast cancer into the different molecular subtypes. Heterogeneous tumors were subjected to laser microdissection using the MMI CellCut system to separate morphologically different tissue areas for subsequent expression analysis.