Fig. 3

PAT-H-MS coupled with laser microdissection. a Schematic representation of the procedures used to isolate histones from FFPE mouse spleen using the classical PAT-H-MS approach (right) or LMD-PAT-H-MS (left). The appearance of extracted histones using the two procedures is shown for two representative breast cancer samples (LuA1 and TN1). b H&E staining for LuA1 and TN1 sections. The encircled areas show the microdissected tumor cells. Scale bar = 10 mm. c Number of sections and histone octamer yields for six breast cancer luminal A-like (LuA) or triple negative (TN) samples (including the samples LuA1 and TN1 (bold) show in a and b). d Elution profiles of H3-modified (27–40) forms for sample TN1, which was processed using LMD-PAT-H-MS from one section of starting material. Extracted ion chromatograms (XICs) for 14 differentially modified forms are displayed