Imaging secondary ion mass spectrometry (SIMS) has been used on a number of tissues samples, mainly brain sections to successfully identify and localise different chemical components to various areas of the tissue^[1]. Compared to other methods like traditional histology or fluorescence staining, the main advantage of SIMS is the label free detection of a large number of different molecules within one experiment on the same tissue section.

With the J105- 3D Chemical Imager, fitted with a newly developed 40 kV gas cluster ion gun^[2], we are now able to overcome some previous limitations of ToF-SIMS analysis and image large intact molecular species at high spatial and high mass resolution simultaneously. To capitalise on these improved capabilities we performed imaging SIMS on fresh frozen hydrated and freeze dried, ductal mammary breast cancer sections, followed by H&E staining of the analysed sections. We showed that with SIMS it is possible to distinguish between different areas of the diseased tissue.

Multivariate analysis facilitates localizing and grouping the up to 10,000 different signals generated from the tissue to produce comprehensive chemical profiles assigned to different areas in the tissue and reveals underlying structures. This way, we have identified a number of molecules which can be, due to high spatial resolution, clearly assigned to the cancerous regions, characterised by staining, in different breast cancer sections. Our results agree with findings from experiments using different methods, which confirm these molecules to be cancer markers while also elucidating new information form the tissue with cellular resolution.

[1] Brunelle, A., and O. Laprevote. Current Pharmaceutical Design 13, no. 32 (2007): 3335-3343.

[2] Angerer, Tina B., Paul Blenkinsopp, and John S. Fletcher. International Journal of Mass Spectrometry 377, no. 0 (2015): 591-598