In contrast, YKL-40 overexpression significantly shortened the overall survival of nude mice implanted with WZ12 Y+ GSCs, knockdown of YKL-40 prolonged the overall survival of nude mice implanted with WZ27 Y− and WZ31 Y− GSCs (Fig. 2g, right), suggesting a positive role of YKL-40 in tumor initiation or progression in these GSCs (WZ12 vs. WZ05 Y+ P = 0.032; WZ27 vs. WZ27 Y− P = 0.005; WZ31 vs. WZ31 Y− P = 0.011). This evidence concerns the gene CHI3L1 and neoplasm.