AFP and gastric cancer: Table 4 shows that the positive levels of AFP (OR = 3.803), CEA (OR = 6.633), CA125, CA199 (OR = 6.234), and CA242 (OR = 6.372) was significantly related to gastric cancer (P < 0.001), After CA125 was stratified by age, patients older than 54 years had an OR of 16.673, the 95% CI was [2.243–123.91], P < 0.001, and the risk of CA125-positive patients being diagnosed with gastric cancer was 16.673 times that of CA125-negative patients.