Figure 4.

Validation of UM data sets by conventional histology. (A) Optical slicing of the cleared KPL-4 tumor sample was performed by UM to receive a stack of single virtual tumor tissue slices. Thereafter, the tumor specimen was paraffin embedded and conventionally cut into serial tissue slices. Different targets of the tumor tissue slices were stained by classic IHC. The virtual slices of the different fluorescence channel were compared to conventional histology to show the validity of UM. (B–D) The direct comparison between tumor tissue information from the virtual autofluorescence UM slice (B) and conventional fluorescence histology (C; DAPI) and classic IHC staining (D; H&E) showed nearly identical tissue structures. (E–G) The virtual UM slice of the lectin-Alexa 647-stained tumor vasculature from E provided also a great morphologic accordance to the conventional fluorescence histology (F; lectin-Alexa 647) and classic IHC vessel staining (G; anti-CD34). (H–J) The penetration and binding behavior of trastuzumab-Alexa 750 in the tumor tissue after 6 hours of incubation showed nearly identical distribution pattern in virtual UM (H) and conventional fluorescence histology (I). (J) The IHC staining of the extracellular HER2 receptor domain (anti-HER2, SP3) provided the expression level of all available HER2 tumor cell receptors. (B–J) Single slice, 5-µm diameter. Scale bar, (A) 500 µm and (B–J) 250 µm.