SPRY2 and glioblastoma: Due to the genetic heterogeneity of GBM cell lines [54], SPRY2 was overexpressed (SPRY2-OE) in U251 cells with low endogenous SPRY2 levels and downregulated (shSPRY2) in SF126 cells with high endogenous SPRY2 protein (Figure 1A,B).