GPC1 and metastatic neoplasm: GPC1 was the only isoform that appeared underexpressed in both metastatic and non-metastatic tumors (Fig. 1a and b); in metastatic tumors, its levels were reduced in 80 % of the cases analyzed (p = 0.03), being around 25 % of those determined in healthy tissues (Fig. 1c); meanwhile, in non metastatic tumors, its levels were reduced in all cases analyzed (p < 0.01), and their values were around 18 % of those determined in healthy tissues (Fig. 1c).