Helix Pomatia (HPA) and carcinoembryonic antigen (CEA) staining were studied in 113 primary breast carcinomas, 63 metastatic lymph nodes and 10 resected local recurrences, using the avidin-biotin-peroxidase complex (ABC) method. Positive percentage rates were 41 (46/113) for HPA and 24 (27/113) for CEA in primary tumors, and 80 (8/10) for HPA but only 10 (1/10) for CEA in metastatic lesions. HPA staining showed a statistically significant correlation with negative estrogen receptor (ER) status (r -0.25, P = 0.05) and high nuclear grade (r 0.20, P = 0.04). Cancers with positive HPA staining were associated with a lower survival rate than those without (P = 0.0001), irrespective of menopausal status. CEA staining showed a marginal correlation with survival (P = 0.06: log rank test). The five-year survival rate of 21 cases positive for these two markers was only 5%. Multivariate analysis revealed HPA staining to be the best prognostic factor. The data indicated that HPA staining might be a valuable prognostic factor for breast cancer patients, especially when combined with CEA staining.