Fig. 2

Immunohistochemistry of ALDH1A3 in GBM. a H&E staining defined the different regions in GBM sections. TC: tumor center; TI: tumor infiltrative area; and TD: tumor distant area. b, c Immunostaining of ALDH1A3 in GBM sections revealed heterogeneous expression of ALDH1A3 in different GBM patient sections (n = 30). The representative photos show the absence of ALDH1A3 expression b and the positive expression of ALDH1A3 c, respectively, in two GBM cases. The positive ALDH1A3 expressing cells were mainly detected in TI, and much less in TC. d-f Images are representative of the expression of ALDH1A3 in the different regions of GBM tissue. g-k Expression of ALDH1A3 in typical tumor cells (arrows in g), in out-layer of glomeruloid tufts (arrows in h), in some vessels (arrows in i), in multi-nuclear cells (arrow in j) and in glial-shaped cells (arrowheads in j). ALDH1A3 immunoreactivity was not detected in the necrosis core (asterisk in k) and the pseudopalisade structure (arrows in k). l ALDH1A3 immunoreactivity was not detected in the non-tumoral control brain section. a-c, original magnification × 100; d-j, original magnification × 400; k-l, original magnification × 200