By KLF4-mCpG binding, neuronal guanine nucleotide exchange factor (NGEF), Rho/Rac guanine nucleotide exchange factor 2 (ARHGEF2), and RAB guanine nucleotide exchange factor 1 (RABGEF1) are upregulated, ultimately promote mitochondrial fusion and further provide a metabolic advantage for glioblastoma cells by improving respiratory reserve capacity under nutritional stress (Wang et al., 2018). The gene discussed is ARHGEF2; the disease is glioblastoma.