IDH1 and neoplasm: However, a few tumor cells existed outside of the margin of the foci-tumor region, and the diffused tumor cells were confirmed in an immunochemistry stained image (isocitrate dehydrogenase 1 [IDH1, 1/80, clone H09, Dianova, Germany] stain, Materials and Methods) and not in a H&E stained image (Fig. 3c–f).