CEACAM5 and esophageal squamous cell carcinoma: Regarding diagnostic accuracy, the review question was set as “Which serum marker has the highest diagnostic ability for ESCC?” and we performed a meta‐analysis of four studies [25, 35, 36, 37] in which three markers, namely SCC‐Ag, CEA, and CYFRA21‐1, were measured concurrently, and true‐positive (TP), false‐positive (FP), and false‐negative (FN) rates were extracted.