One study developed a customized an antibody microarray platform containing 4096 features to interrogate plasma samples spanning pre-invasive and invasive diseases from a mouse model of pancreatic ductal adenocarcinoma (PDA) [18]. They found a protein signature, comprising of the differential expression of three proteins, ERBB2, TNC and ESR1, which could be used to improve the AUC from 0.86 (95% confidence interval [CI] 0.76–0.96) to 0.97 (95% CI 0.92–1.0) when the PDA marker CA19-9 included. This evidence concerns the gene ESR1 and Patent ductus arteriosus.