The authors used helix pomatia agglutinin (HPA) staining to examine 163 primary gastric carcinoma isolates, using the avidin-biotin-peroxidase complex method. The positive HPA staining rate was 59% (96/163) for the primary tumors, and the positive staining correlated well (with statistical significance) with tumor enlargement, penetration, lymphatic invasion, and metastasis (P less than 0.01), and with infiltrative spread (P less than 0.05). Patients with gastric cancer showing positive HPA staining had a lower survival rate (P less than 0.001), particularly when the cancer cells were present on the serosal surface. Careful follow-up and intensive postoperative therapy are required for patients with an HPA-positive advanced gastric carcinoma.