Additional file 9: Figure S1. qRT-PCR analysis of selected genes in TMZ-treated cells. a The relative gene expression ratios (fold-change) of stem cell markers CD133, OCT4, SOX2, and NANOG. b The relative gene expression ratio (fold-change) of MGMT. Gene expression fold-change values were derived by 2-ΔΔCT method (expressed as ratios relative to control values after normalization to the internal control TBP). TBP – TATA-binding protein; CD133 – prominin 1; OCT4 – POU class 5 homeobox 1; SOX2 – SRY (sex determining region Y)-box 2; NANOG – Nanog homeobox; MGMT – O-6-methylguanine-DNA methyltransferase