HISTOCHEMISTRY TO DETECT HELIX-POMATIA LECTIN-BINDING IN BREAST-CANCER - METHODOLOGY MAKES A DIFFERENCE

A number of studies have shown that altered cellular glycosylation, as detected by binding of Helix pomatia lectin to paraffin sections, is associated with metastatic disease and consequent poor patient prognos is in breast and other cancers, In a 24-year retrospective study, sect ions of 373 primary breast cancers were stained for binding of the lec tin using two different histochemical techniques: a direct method (usi ng peroxidase-conjugated lectin) and an indirect method (using native, unconjugated lectin). Similar percentages of cases were positive (79% ) and negative (21%) for lectin binding with either technique, but the re was enormous inconsistency when individual cases were examined, A t otal of 38/373 (10.2%) cases that were negative by the indirect method were positive by the direct method, and 37/373 (9.9%) cases that were negative by the direct method were positive by the indirect method. L ife tables calculated for lectin staining vs nonstaining cases showed a very strong correlation between lectin binding and long-term surviva l (p < 0.0001) when staining was performed by the indirect method, but only very weak correlation with prognosis (p < 0.03, borderline signi ficance) when the direct technique was employed, SDS-PAGE revealed tha t there were differences in breast cancer glycoproteins recognized by native lectin and peroxidase-conjugated lectin immobilized on Sepharos e 4B affinity beads, Helix pomatia lectin binding appears to be an int riguing and potentially valuable marker of biological behavior in brea st cancer, This study emphasizes the importance of selecting an approp riate immunohistochemical technique for its visualization.