Fig. 1
Seven PTP genes display significantly different expression levels in lower grade gliomas and glioblastomas. a Heat map of qPCR-based PTP expression levels – as determined in 19 WHO grade II, 15 WHO grade III and 49 WHO grade IV glioma samples – separated on malignancy grade and normalized per PTP as Z-scores. PTPs are represented in reverse alphabetical order ranging from TNS3 at the top to ACP1 at the bottom. b Overall PTP expression level difference between grade II, III or IV glioma samples and normal brain control tissue. The mean ΔΔCt value over the 91 PTP primer sets in the grade II, III or IV samples is plotted. Bars indicate SEM; black triangles in grade IV bar represent secondary glioblastoma samples. Significance of mean expression differences between grades was calculated using Kruskal-Wallis one way analysis of variance with post-hoc Dunn’s Multiple Comparison Test (n.s. indicates non significant; * p < 0.05; ***p < 0.001). c Graph showing differential expression between lower grade (WHO grade II-III) and glioblastoma (WHO grade IV) glioma samples for seven PTPs on a 2log scale. PTP mRNA expression levels were determined by qRT-PCR, normalized to β-actin transcript levels, and depicted relative to the levels in histologically normal brain tissue. Values obtained in the first cohort of tumor samples are depicted [see Additional file 2]. Error bars indicate standard error of the mean (SEM). Asterisks indicate significance levels (** p < 0.01; *** p < 0.001) as determined by the two-tailed Student’s t-test