Circulating Tumor DNA as a Novel Biomarker for Pancreatic Cancer

Despite some therapeutic advances in the past years, pancreatic ductal adenocarcinoma (PDAC) still has a dismal prognosis. One explanation is the lack of reliable biomarkers wherefore screening has been hampered. In turn, early tumor detection is still the exception. The sole clinically established tumor marker is the serum carbohydrate antigen 19-9 (CA19-9), but its use is due to only moderate sensitivity and specificity restricted to patients’ follow-up. The use of biomarkers in basic and clinical research as well as in clinical practice has become common in a variety of tumors, and even study endpoints nowadays operate based on their outcome. However, no clinical used biomarkers exist in the case of PDAC. Circulating tumor DNA (ctDNA) derived either from exosomes or directly from the bloodstream originating from a given cancer might have the capacity to circumvent this hurdle. Eventually ctDNA can in the future provide (i) a diagnostic tool for early diagnosis allowing cure in case of primary disease but also relapse, (ii) the opportunity to monitor and detect the disease progression, (iii) therapeutic decision guide based on the mutational makeup of the primary PDAC, and (iv) guidance to react chemotherapy-driven tumor evolution.