PPA1 and gastric cancer: In the past decades, proteomic analysis based on two-dimensional polyacrylamide gel electrophoresis and mass spectrometry has revealed that the expression of PPA1 is significantly increased in lung adenocarcinoma (4), primary colorectal carcinoma (5), infiltrating ductal carcinoma of the breast (6), prostate cancer (7), gastric cancer (8), liver cancer (9), large B-cell lymphoma (10), and ovarian cancer (11), compared with that in the corresponding normal or paraneoplastic tissues.