MUC2 and Patent ductus arteriosus: We found that MUC1 protein in MA or SRCC group was significantly lower than that in the HMDA and PDA groups (P < 0.001, Table 2), and MUC2 in MA or SRCC group was significantly higher than that in the PDA groups (P = 0.013, Table 2), but PGC protein had no significant difference in the GC group.