Although our research shows for the first time that the detection of serum SPRR2A can play a complementary role in the diagnosis of GC, especially when combined with the detection of serum CEA, there are still some limitations of this study: First, this prospective study selected a small number of gastric cancer cases and a relatively simple tissue type (only gastric adenocarcinoma). This evidence concerns the gene CEACAM5 and gastric adenocarcinoma.