Altres ajuts: This work was supported by grants from the Spanish Ministerio de Economía y Competitividad/ISCIII-FEDER, the Carmen Delgado/Miguel Pérez-Mateo AESPANC-ACANPAN 2016 grant and the "Generalitat de Catalunya" to P.N., , EU TRANSCAN AC14/00033 and AECC grants to A.C., and grants from Instituto de Salud Carlos III/FEDER and the "Xarxa de Bancs de tumors" sponsored by Pla Director d'Oncologia de Catalunya (XBTC). CAO received funding from the International PhD studies Fellowship "Créditos Beca Francisco José de Caldas" n° 529-2011 Colciencias, Colombia.

Pancreatic ductal adenocarcinoma (PDA) is the most frequent type of pancreatic cancer and one of the deadliest diseases overall. New biomarkers are urgently needed to allow early diagnosis, one of the only factors that currently improves prognosis. Here we analyzed whether the detection of circulating galectin-1 (Gal-1), a soluble carbohydrate-binding protein overexpressed in PDA tissue samples, can be used as a biomarker for PDA. Gal-1 levels were determined by ELISA in plasma from healthy controls and patients diagnosed with PDA, using three independent cohorts. Patients with chronic pancreatitis (CP) were also included in the study to analyze the potential of Gal-1 to discriminate between cancer and inflammatory process. Plasma Gal-1 levels were significantly increased in patients with PDA as compared to controls in all three cohorts. Gal-1 sensitivity and specificity values were similar to that of the CA19-9 biomarker (the only FDA-approved blood test biomarker for PDA), and the combination of Gal-1 and CA19-9 significantly improved their individual discriminatory powers. Moreover, high levels of Gal-1 were associated with lower survival in patients with non-resected tumors. Collectively, our data indicate a strong potential of using circulating Gal-1 levels as a biomarker for detection and prognostics of patients with PDA.