IGFBP5 and central nervous system cancer: Then, cck-8 assay was performed and the results showed that inhibition of IGFBP5 could significantly reduce the cell viability of glioma cell lines U251 (Figure 8D, E) and U87 (Figure 8F, G), whereas IGFBP5 overexpression dramatically promoted cell proliferation (Figure 8H, I) and colony formation (Figure 8J) in U251 cell lines.