Validation of DeepQuanTR results. Immunostainings of the lymphoma/normal liver border (scale bars represent 200 μm) and with higher magnification of hepatic lymphoma lesions (scale bars represent 50 μm) using antibodies against 8 candidate antigens found to be up-regulated in the proteomic analyses are presented. Proteins of interest are shown in red, CD31 in green, and nuclei in blue. Lymphoma nodules are easily identified by a higher cellular density. Costaining with CD31 revealed that proteins from different localizations within the bloodstream-accessible tissue compartments (vascular endothelial cells, subendothelial matrix and stroma, perivascular tumor cells) have been modified by in vivo biotinylation and identified using DeepQuanTR. Dotted lines in merged images indicate the tumor/liver border. Slides were viewed with an LSM510 Meta confocal microscope (Carl Zeiss) using 10×/0.45 W and 40×/1.2 W water objectives and Fluorescent Mounting Medium (Dako). Images were acquired with the LSM510 Meta confocal laser scanning microscope and software provided by the manufacturer (Carl Zeiss). Images were manipulated using ImageJ software, Version 1.42q (available at http://rsb.info.nih.gov/ij/).