Figure 1
From: Epigenetic modulation of the drug resistance genes MGMT, ABCB1 and ABCG2 in glioblastoma multiforme
Correlation analyses between MGMT, ABCB1 and ABCG2 mRNA expression and mean promoter methylation as well as comparison of MGMT, ABCB1 and ABCG2 promoter methylation between glioblastoma and non-malignant brain samples. Correlation analysis of mRNA expression [2-∆∆CT] and promoter methylation [%] was performed for 20 GBM specimens (A, C, E). Comparison of MGMT promoter methylation [%] between 64 GBM and 7 non-malignant brain specimens (B, D, F) (A) Correlation of MGMT mRNA expression and MGMT promoter methylation (Spearman’s rank correlation coefficient: -0.474; p = 0.035), (C) ABCB1 mRNA expression and ABCB1 promoter methylation (Spearman’s rank correlation coefficient: 0.242, p = 0.304), and (E) ABCG2 mRNA expression and ABCG2 promoter methylation (Spearman’s rank correlation coefficient: -0.170, p = 0.474). (B) Comparison of MGMT promoter methylation between GBM and non-malignant brain specimens (Mann–Whitney U test, p < 0.001), (D) ABCB1 promoter methylation between GBM and non-malignant brain samples (Mann–Whitney U test, p = 0.007), and (F) ABCG2 promoter methylation between GBM and non-malignant brain specimens (Mann–Whitney U test, p = 0.051).