Indeed, measurement of cyst fluid carcinoembryonic antigen (CEA) levels has been extensively investigated as a diagnostic tool to differentiate precancerous mucinous cysts — IPMNs and mucinous cystic neoplasm (MCN, another less common PDAC precursor) — from benign cysts such as serous cystadenomas. Here, CEACAM5 is linked to serous cystadenoma.