CEACAM5 and gastric cancer: Compared with traditional diagnostic biomarkers (CEA, CA724, and CA199), circulating exosomal lncRNA PCSK2–2:1 (proprotein convertase subtilisin/kexin type 2–2:1) and GNAQ-6:1 (G protein subunit alpha q-6:1) have been reported as better biomarkers for distinguishing gastric cancer patients from healthy people.