POU5F1 and glioblastoma: Thus, we measured the messenger RNA (mRNA) expression of the stem cell markers krüppel-like factor 4 (KLF4), octamer binding transcription factor (OCT4), and Nestin in native U251MG and U87MG GBM cells treated with solely TMZ, AT101, or the combination of TMZ plus AT101 in stem-like cell-conditioned media including the different control samples (Figure 5).