Localization of lactoferrin and nonspecific cross-reacting antigen in human breast carcinomas. An immunohistochemical study using the avidin-biotin-peroxidase complex method.

A retrospective immunocytochemical study was performed on 67 human breast carcinomas to determine whether the epithelial cell-associated antigens, lactoferrin and nonspecific cross-reacting antigen (NCA), could be used as markers in the prognostic assessment of breast cancers. Fixed paraffin sections were tested with anti-lactoferrin and anti-NCA. Lactoferrin and NCA were found in 7.5% and 19% of the cases, respectively. Furthermore, the association between these two antigens in tumor cells was significant (P less than 0.05). Kappa-casein was observed in all antigen-positive cases. These antigens were observed more often in low-grade ductal carcinomas that had positive estrogen and progestin receptors, but no relationship could be established between lactoferrin or NCA and other prognostic indicators, such as histologic type and grade of the tumor, stromal elastosis, or steroid receptors. Although more antigen might have been detected in unfixed, frozen specimens, the results indicate that lactoferrin and NCA possess minimal value as epithelial cell markers and no prognostic value when detected on routinely fixed, paraffin-embedded samples.