By comparing the 2-DE maps of the four groups (PDA, healthy subjects, other malignancies and chronic pancreatitis patient sera), only nine proteins were recognized by PDA patient antibodies, namely triosephosphateisomerase 1 (TPIS), retinal dehydrogenase 1 (AL1A1), glucose-6-phosphate 1-dehydrogenase (G6PD), elongation Factor Tu (EFTU), isocitrate dehydrogenase (IDHC), keratin 10 (K1C10), cofilin-1 (COF1), transgelin (TAGL) and alpha-enolase (ENO1). The gene discussed is ALDH1A1; the disease is Patent ductus arteriosus.