GPC3 and breast cancer: Current studies show that the expression level and the biological role of GPC3 in different cancer species are quite different, for example, it was highly expressed in Wilms tumor (42), yolk sac tumor (43), hepatocellular carcinoma (44) and clear cell ovarian cancer (45); while its expression in mesothelioma (46), lung adenocarcinoma (47), clear cell renal cancer (48), gastric cancer (49), and breast cancer (50) was inhibited.