Sialyi Le
x (FH6) and sialyl Le
a (CA19—9) antigens, members of a family of high molecular weight glycoproteins, are ligands for E-selectin and may play important roles in tumor metastasis. However, expression patterns of sialyl Le
x and sialyl Le
a have not been established in human extrahepatic bile duct cancer. In this study, we examined sialyl Le
x and Le
a expression in human extrahepatic bile duct adenocarcinoma and their clinicopathological significance. Sialyl Le
x immunoreactivity was detected not only in cancer cells (cytoplasmic type; 57.7%, 30/52), but also in cancer stroma (stromal type; 19.2%, 10/52). Sialyl Le
a immunoreactivity was found in cancer cells (cytoplasmic type; 84.6%, 44/52) and in cancer stroma (stromal type; 63.5%, 33/52). Stromal sialyl Le
a expression was more frequent than stromal sialyl Le
x expression (p<0.001). According to TNM classification, cytoplasmic sialyl Le
x and sialyl Le
a expression was detected in 62.5% (30/48) and 85.4% (41/48) of the T2-3 cancers (T2-3 vs T1, sialyl Le
x, p = 0.015; and sialyl Le
a, p = 0.310). Cytoplasmic sialyl Le
a positive cancers frequently showed lymph node metastasis (p = 0.029). These obseivations suggested that sialyl Le
a expression plays more important roles than sialyl Le
x in metastasis of human extrahepatic bile duct adenocarcinoma.
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