GPC5 and neoplasm: Furthermore, analysis of glypican 5 protein expression in relation to diagnosis features showed a significant level of positive correlation with tumor grade (rs = 0.43), reflecting the increase in expression in tumors of grade 2 or higher (Figure 9B), as well as with respect to tumor stage (rs = 0.48) since expression increased in tumors of stages 3 and 4 (Figure 9C).