A PCR blood test outperforms chromogranin A in carcinoid detection and is unaffected by PPIs

A critical requirement in neuroendocrine tumor (NET) management is a blood biomarker test that is sensitive, specific and reproducible. We evaluated a PCR-based 51-transcript signature to detect tumors, compared it with chromogranin A (CgA) and examined the confounding effect of proton pump inhibitors (PPIs), which cause falsely elevated CgA levels. The multigene signature was evaluated in two groups. Group 1: 125 prospectively collected NETs: gastroenteropancreatic NETs (nZ91, including 42 pancreatic and 40 small intestinal), carcinoids of unknown primary(nZ18) and other sites(nZ16). Group2: prospectively collected non-NET patients receiving PPIs (O1 month; dyspepsia, nZ19; GERD, nZ6; and pancreatitis, nZ4)and50controls.