The binding of peroxidase-labelled lectins to human breast epithelium. I--Normal, hyperplastic and lactating breast.

Six peroxidase-labelled lectins have been applied to tissue sections of normal, hyperplastic and lactating human breast. The effect of fixation on binding has been assessed by the comparison of specimens treated with a variety of fixatives with frozen material; the effect of trypsin has also been considered. The other objective has been to establish the consistency of lectin reactivity with this non-malignant breast tissue. Fixation has little effect on the binding of wheat germ agglutinin and peanut lectin, although reactivity with the latter was sometimes increased above that seen in frozen material by the use of Bouin's fluid. Trypsinization of formalin-fixed tissue appears to be a prerequisite for staining with soy bean agglutinin and Ulex europeus. The binding of Lotus tetragonolobus and Dolichos biflorus to fixed tissue has been found to be unreliable in comparison to frozen samples. Soy bean agglutinin and Dolichos biflorus, both specific for N-acetyl-D-galactosamine, have binding patterns which vary between specimens and often between themselves. Of the two fucose-binding lectins Ulex europeus has shown a variability of reaction between specimens, whilst Lotus tetragonolobus consistently reacts with ductal and acinar epithelium but with varying intensities. Consistent binding patterns have been found for wheat germ agglutinin and peanut lectin, the latter after the use of neuraminidase. They therefore form a useful basis for comparison with the reactivity of malignant breast tissue.