This study documents modifications in the expression and the cellular distribution of binding sites for a 16 kDa chick embryo
lectin (CL16-BS) in
breast cancer. This
lectin binds preferentially to terminal and penultimate
N-acetyllactosamine residues (Galbeta1-4GlcNAc). BS density and distribution, studied by
lectin binding followed by indirect immunofluorescence, were compared in normal breast tissues and 45 invasive
carcinomas (lobular and ductal). Increased number of fluorescent epithelial cells (ETC+) were observed in normal ducts adjacent to
lobular carcinomas and in
tumors from both types when compared to normal glands. In
ductal carcinomas, a significant diminution of ETC+ percentage was observed in the highest anatomopathological SBR grades: 32.7% in grade III, 80.8% in grade II and 66.5% in grade I (p<0.001). For both lobular and
ductal carcinomas, ETC+ percentages were also positively correlated with low versus high MSBR grades (p<0.002). The subcellular distribution of CL16-BS varied according to the
tumor type and/or the histological grades. It was mostly membrane-associated in low SBR and MSBR grades (p<0.001 and p<0.01, respectively) and cytoplasm-associated in high grades (p<0.02 and p<0.05). Some of these parameters were also correlated with certain other clinicopathological factors, such as
tumor size (p<0.02), high S-phase cell fraction (p<0.04 and p<0.03) and low density
estrogen receptors (p<0.05). Diminution in CL16-BS density and cytoplasmic versus membrane localization may be considered as indicators of
tumor progression but not of
metastasis.