Owing to the fact that hGluc is secreted by MSCs and to its diluted and limited signal under whole animal imaging conditions with IVIS Lumina [40] (data not shown), we used MSCs engineered with intracellular Fluc-tdT [41] for real-time imaging and localization of MSCs in tumors in situ. Fluc-tdT-MSCs were simultaneously labeled with red fluorescent protein (RFP) to assess Fluc transduction efficiency and to image any co-localized MSCs and tumor cells in subsequent ex vivo immunohistochemistry. Here, DNTT is linked to neoplasm.