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Background: We explored, within the EORTC10994 study, the outcomes for patients with molecular apocrine (MA) breast cancer, and defined immunohistochemistry (IHC) as androgen-receptor (AR) positive, oestrogen (ER) and progesterone (PR) negative. We also assessed the concordance between IHC and gene expression arrays (GEA) in the identification of MA cancers., Methods: Centrally assessed biopsies for AR, ER, PR, HER2 and Ki67 by IHC were classified into six subtypes: MA, triple-negative (TN) basal-like, luminal A, luminal B HER2 negative, luminal B HER2 positive and "other". The two main objectives were the pCR rates and survival outcomes in the overall MA subtype (and further divided by HER2 status) and the remaining five subtypes., Results: IHC subtyping was obtained in 846 eligible patients. Ninety-three (11%) tumours were classified as the MA subtype. Both IHC and GEA data were available for 64 patients. In this subset, IHC concordance was 88.3% in identifying MA tumours compared with GEA. Within the MA subtype, pCR was observed in 33.3% of the patients (95% CI: 29.4-43.9) and the 5-year recurrence-free interval was 59.2% (95% CI: 48.2-68.6). Patients with MA and TN basal-like tumours have lower survival outcomes., Conclusions: Irrespective of their HER2 status, the prognosis for MA tumours remains poor and adjuvant trials evaluating anti-androgens should be considered.

Lipid-based biomarkers for research and diagnosis are rapidly emerging to unpack the basis of person-to-person and population variations in disease susceptibility, drug and nutritional responses, to name but a few. Hence, with the advent of MALDI Mass Spectrometry Imaging, lipids have begun to be investigated intensively. However, lipids are highly mobile during tissue preparation, and are soluble in the solvent used for matrix preparation or in the fixing fluid such as formalin, resulting in substantial delocalization. In the present article, we investigated as another alternative, the possibility of using specific dyes that can absorb UV wavelengths, in order to desorb the lipids specifically from tissue sections, and are known to immobilize them in tissues. Indeed, after lipid insolubilization with chromate solution or chemical fixation with osmium tetroxide, heterocyclic-based dyes can be directly used without matrix. Taking into account the fact that some dyes have this matrix-free capability, we identified particular dyes dedicated to histological staining of lipids that could be used with MALDI mass spectrometry imaging. We stained tissue sections with either Sudan Black B, Nile Blue A, or Oil Red O. An important advantage of this assay relies on its compatibility with usual practices of histopathological investigation of lipids. As a new method, DALDI stands for Dye-Assisted Laser Desorption Ionization and allows for future clinical and histopathological applications using routine histological protocols. Additionally, this novel methodology was validated in human ovarian cancer biopsies to demonstrate its use as a suitable procedure, for histological diagnosis in lipidomics field.

Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) and profiling technology have become the easiest methods for quickly accessing the protein composition of a tissue area. Unfortunately, the demand for the identification of these proteins remains unmet. To overcome this bottleneck, we combined several strategies to identify the proteins detected via MALDI profiling including on-tissue protein extraction using hexafluoroIsopropanol (1,1,1,3,3,3-hexafluoro-2-propanol, HFIP) coupled with two-dimensional cetyl trimethylammonium bromide/sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2D CTAB/SDS-PAGE) for separation followed by trypsin digestion and MALDI-MS analyses for identification. This strategy was compared with an on-tissue bottom-up strategy that we previously developed. The data reflect the complementarity of the approaches. An increase in the number of specific proteins identified has been established. This approach demonstrates the potential of adapted extraction procedures and the combination of parallel identification approaches for personalized medicine applications. The anatomical context provides important insight into identifying biomarkers and may be considered a first step for tissue-based biomarker research, as well as the extemporaneous examination of biopsies during surgery.

MALDI mass spectrometry imaging (MALDI-MSI) is currently used for clinical applications, such as biomarker identification, particularly for the study of solid tumors. The ability to map specific compounds that have been determined to be biomarkers and therapeutic targets is relevant for the evaluation of the efficacy of targeted therapies. This article describes a new method called Spectro-ImmunoHistoChemistry (SIHC), which combines the use of specific antibodies against markers and mass spectrometric imaging in the MS/MS mode. SIHC is based on direct primary antibody-antigen recognition, trypsin digestion of the antibody overlaying the markers of interest in the tissue section, and MALDI-MSI of the tryptic peptides generated from the antibody. This approach has both clinical and pharmacological applications. First, it can be used as a cross-validation method to monitor the presence specifically of a marker in a tissue section. Second, SIHC could potentially be used as a novel technology for tracking specific antibodies after in vivo injection for anti-cancer treatments. Additionally, SIHC could enable novel clinical applications of MSI, such as monitoring the efficacy of cytotoxic antibody treatments.