CGA and neoplasm: An analysis of the individual GEP tumor sites (n=91) identified that the PCR test was positive in 95–100% of samples (gastric, 100%; duodenum, 100%; pancreas, 95%; small intestine, 100%; appendix, 100%; and colorectal, 100%); CgA positivity ranged between 0 and 58% (gastric, 0%; duodenum, 0%; pancreas, 29%; small intestine, 58%; appendix, 33%; and colorectal, 33%; Fig. 1B).