To evaluate whether there is an interdependence between the amount of glioma stem cells and the sensitivity of the studied cultures to the virus, we assessed the CD133 and CD44 levels, the most common markers of glioblastoma stem cells [12], in U87 MG, U343 MG, MG1, BR1.20, and BR3.20 cell cultures by flow cytometry (Figure 2). The gene discussed is CD44; the disease is glioblastoma.