MMP2 and central nervous system cancer: Having established that SmVAL9 was excreted/secreted during the process of miracidium to sporocyst transformation (Figs. 3 and 4A) and a previous study demonstrating that mammalian RTVP-1 (a SmVAL9 homolog) up-regulated gelatinase A/MMP2 expression in glioma cells and influenced the invasion of astocytic tumors (Rosenzweig et al., 2006), we postulated that a conserved function in tissue remodelling was possible for E/S SmVAL9.