To the Editor: Pancreatic ductal adenocarcinoma (PDAC) is the only one of the five most lethal malignancies (lung, colorectal, breast, pancreatic, and prostate cancer) for which both the incidence rate and death rate have increased in recent years, and with a projected increase in the number of deaths. The lack of early symptoms results in late-stage detection and a near to 100% mortality rate, despite improvements in therapies (1, 2, 3). Therefore, there is an urgent need for novel screening strategies to recognize early cancers or precursor lesions in the general population, and in individuals that are considered at highest risk on the basis of clinical or genetic characteristics. Owing to the vast genetic heterogeneity of this cancer, no single biomarker exists that is strongly correlated with its diagnosis. Efforts for detecting pancreatic adenocarcinoma at early stages are, therefore, focused on the identification of a large panel of appropriate sensitive and specific serum biomarkers, including some already characterized candidates and clearly novel ones (1, 4).

Recently, we reported that the intracellular anti-apoptotic protein BAG3 (5) was expressed in all 346 PDAC tumor samples examined, and not in the surrounding non-neoplastic tissue or in normal pancreas (6). Furthermore, in a cohort of 66 patients who underwent R0 resection, the level of BAG3 expression inversely correlated with patient survival (6). These results prompted us to investigate whether BAG3 protein was also present in patients’ sera and could potentially be used as a biomarker for PDAC.