The lectin-binding sites for peanut agglutinin in invasive breast ductal carcinomas and their metastasis.

Peanut agglutinin (PNA) lectin-binding site patterns in primary invasive breast ductal not otherwise specified (NOS) carcinomas are related to aggressiveness of the tumor. The present study was designed to compare the expression of PNA-binding sites in the primary tumor and in local lymph node metastases. The expression of lectin-binding sites was studied using the avidin-biotin complex/immunoperoxidase technique and analyzed in relation to age of the patient and size of the breast cancer. Breast cancers and their metastases showed negativity or positivity, the latter being divided into "apical" and "non-apical" (i.e. membrane and/or cytoplasmic) depending on the main localization of staining in tumor cells. No correlation was found between primary tumors and metastases as regards PNA-binding patterns, which confirms the opinion that advanced primary tumors are polyclonal and that selected subclones of malignant cells give rise to metastases. Furthermore, the fact that primary tumors with PNA non-apical expression, a feature related to aggressiveness and poor differentiation, may have lymph node metastases with apical expression, suggests that this pattern, although no longer evident in the primary tumor, is involved in the process of cell metastasis.