GPC3 and congenital secretory chloride diarrhea 1: We found that the serum GPC3 level of patients in the HCC group was 6.49 (1.14~28.28) ng/mL, significantly higher than that of the CLD group at 1.71 (0.57~4.16) ng/mL (Z = −4.630, p < 0.001) (Figure 2).