The results from a colony formation assay showed that ECRG4-overexpressing ECRG4-5 and -7 cells formed significantly less colonies than Control clone cells (P < 0.001 for both cell types) (Figure 3B), suggesting an inhibitory effect of ECRG4 on anchorage-dependent growth of glioma cells. This evidence concerns the gene ECRG4 and central nervous system cancer.