The increase in SOX2 levels induced in MCF7 (Figure 4) and MDA-231 (Figure S2) cells (∼2- to 3-fold) were similar to the levels of SOX2 in MCF7 cells engineered to stably overexpress SOX2 [18], as well as the level of SOX2 induction observed in our brain tumor studies presented above. This evidence concerns the gene SOX2 and brain neoplasm.