Expression of ZEB1 in human glial tumors and normal brain.

<p>(A) Biopsy samples of human glial tumors show abundant nuclear expression of ZEB1. Sections from non-neoplastic normal brain show weak cytoplasmic staining of neurons and nuclear expression in astrocytes. (B) Quantification of ZEB1 in full histological sections of gross total resections of human glial tumors. ZEB1 positive cells were quantified using automated image analysis. Dots represent the mean of multiple regions of interest (ROI) per tumor. Box plots show the distribution of the ZEB1 labelling in tumor with indicated integrated diagnosis according the 2016 WHO classification of CNS tumors [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185376#pone.0185376.ref029" target="_blank">29</a>]. (C) <i>ZEB1</i> mRNA expression in public GBM cDNA microarray datasets. Boxplots show distribution in normal brain vs. GBM. Data were retrieved via the GlioVis portal [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185376#pone.0185376.ref030" target="_blank">30</a>].</p

ZEB1 expression in the tumor microenvironment.

<p>(A) Cell type specific expression of ZEB1 in reactive brain tissue. Human brain biopsy samples from cases of seizure-induced reactive gliosis or subacute infarction were co-stained for ZEB1 and Iba1 for microglia, CD45 for leucocytes, CD68 for macrophages and GFAP for astrocytes, respectively. Scale bars 50 μm. (B) Co-labeling of ZEB1 and CD68 or HLA-DR, respectively in human GBM. (C,D) Correlation of microarray-based gene expression levels of <i>ZEB1</i> and myeloid cell markers <i>CD68</i> (C) and <i>AIF1</i> (D), respectively. Processed log₂-transformed intensities from 157 GBM cases studied by Gravendeel et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185376#pone.0185376.ref034" target="_blank">34</a>] were obtained via the GlioVis portal [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185376#pone.0185376.ref030" target="_blank">30</a>].</p

Intratumoral heterogeneity of ZEB1 expression.

<p>(A) Co-labeling of IDH1 R132H and ZEB1 in a case of IDH1 mutant glioblastoma. The image shown has been taken from one out of ten fields of view that were subjected to separate and blinded manual scoring of mutant IDH1 and ZEB1 expression. (B) ZEB1 gradient along the tumor edge of a mesenchymal GBM (BLN-7 parental tumor). ZEB1 IHC, overall cellularity (<i>blue</i>), the relative frequency of ZEB1+ cells (<i>red</i>) and the mean nuclear intensity of ZEB1+ cells (<i>green</i>) at the tumor edge are shown. (C,D) Expression of ZEB1 (<i>pink</i>) and CD68 (<i>brown</i>) in perinecrotic regions with (C) or without (D) pseudopalisades.</p

Intertumoral heterogeneity of ZEB1 expression.

<p>(A) Box plots of ZEB1 labelling index (percent) with respect to EGFR amplification and IDH1 mutation. (B,C) Correlation of ZEB1 expression and Ki67 labelling index or cellularity, respectively, in N = 193 glioblastoma TMA samples. Trend lines indicate linear regression estimates. Note log scale for Ki67 index. (D) Kaplan-Meier estimates of overall survival time (months) with respect to ZEB1 expression. The observed data range of ZEB1⁺ percentages was split into two equally sized bins at the threshold value of 49%.</p