Because of the complexity of action of sFRP4 and because of our earlier observation of targeted inhibition of glioma and head and neck CSCs by sFRP4 (Warrier et al., 2012, 2014; Bhuvanalakshmi et al., 2015), we decided to investigate further a combination effect of DG with sFRP4. This evidence concerns the gene SFRP4 and central nervous system cancer.