No significant difference in AUCs was found between SYCN, REG1B and CA19.9 in discriminating PDAC from disease-free controls (p ≥ 0.4) of Sample Set B (Table 2), and between AGR2 and CA19.9 (p = 0.69) in discriminating PDAC from other cancers (Additional file 1: Table S2). The gene discussed is REG1B; the disease is cancer.