Lectin-histochemical reactivity of sialic acid in breast cancer and its relationship to prognosis using limulus polyphemus agglutinin.

Studies of circulating sialic acid have revealed its relationship with a variety of malignant tumors. It is not vet clear whether sialic acid could be used as a prognostic marker of breast cancer, and few studies have examined sialic acid expression in the cell membrane and cytoplasm of breast cancer cells by means of the lectin-histochemical technique. In the present study, we used biotinylated limulus polyphemus agglutinin (LPA), a special binding lectin of sialic acid, to stain sialic acid in breast cancer cells. Of the 104 cases of breast cancer examined, 59 (56.7%) positive cases were observed. There was a significant correlation between the LPA staining and the clinicopathologic features of all patients, including pathological stage and lymph node metastasis. Among the 100 patients who underwent curative operation, the mean disease-free survival rate of the 45 patients who were LPA-negative was significantly higher than that of the 55 LPA-positive patients (p<0.05). These results suggest that the positive expression of sialic acid in breast cancer could be used as a marker of malignancy potential, as well as a poor survival factor, and the biotinylated LPA assay may provide a convenient and useful method to predict the prognosis of breast cancer.