Typically, patients with unresectable PDAC receive chemotherapy, such as FOLFIRINOX (fluorouracil, leucovorin, irinotecan, and oxaliplatin) or gemcitabine/nab-paclitaxel, and the tumor response is evaluated using imaging modalities or tumor markers, such as carbohydrate antigen 19-9 (CA 19-9) and carcinoembryonic antigen (4–6). This evidence concerns the gene CEACAM5 and neoplasm.