Digital spatial profiling application in breast cancer: a user's perspective.

The disciplines of oncology and pathology are at present experiencing a wave of changes as precision medicine becomes embedded as standard-of-care. Consequently, the need to assess increasing numbers of biomarkers simultaneously has become more urgent and recognising the vast intra-tumoural heterogeneity, including within the microenvironment, requires a complex dimensional understanding of the localisation of the biomarker expression. Digital spatial profiling (DSP; nanoString™) technology spatially resolves and digitally quantifies proteins in a highly multiplexed assay, underpinned by the nCounter® barcoding platform. We present the application of this technology to breast cancer samples. Applying the 'off the shelf' cancer panel and a custom-conjugated E-cadherin antibody, we quantify vast intra-tumoural heterogeneity in immunological and tumour markers, and demonstrate a need for focussed selection of target cell populations. The technology offers enormous potential not only for making research advances but also for improving standard operating procedures in diagnostic applications.