GPC3 and neuroendocrine carcinoma: Later studies evaluating GPC3 protein levels in a small cohort of gastric adenocarcinomas (n=8) and neuroendocrine carcinomas (n=8) suggested that low expression of GPC3 did not correlate with tumor size or tumor differentiation [6], therefore implying GPC3 in gastric oncogenesis but not in the regulation of primary tumor growth.