HSP90AA1 and gastric cancer: Analysis by the GEPIA database revealed (tumor = 408, normal = 211) that CA2 and HSP90AA1 were differentially expressed in gastric cancer, CA2 (p < 0.05) was lowly expressed in gastric cancer, and HSP90AA1 (p < 0.05) was highly expressed in gastric cancer (Figures 4C, D).