Blood vessel invasion, recurrence rate, and time to recurrence were examined in relation to the immunohistochemical expression of proliferating cell nuclear antigen, sialyl LewisX, and sialyl Lewis(a) in 303 patients with lung cancer who had a curative resection from 1980 to 1991. Of these, 150 had adenocarcinoma, 117 had squamous, 21 had large-cell, and 15 had small-cell carcinoma. Significant differences were detected in the expression of proliferating cell nuclear antigen and sialyl LewisX between adenocarcinomas and the other histologic types; thus the subjects were divided into 150 with adenocarcinoma and 153 with non-adenocarcinoma. In those with adenocarcinoma, the frequency of blood vessel invasion was significantly higher in tumors with strong sialyl LewisX expression, and the disease-free survival of the patients with blood vessel invasion was significantly worse when their tumors strongly expressed both sialyl LewisX and proliferating cell nuclear antigen. In those with non-adenocarcinoma, on the other hand, tumors with strong expression of sialyl Lewis(a) and proliferating cell nuclear antigen showed significantly higher frequencies of blood vessel invasion and worse disease-free survival. In patients with recurrent tumors, those with strong proliferating cell nuclear antigen expression showed a significantly shorter time to recurrence. We conclude that sialyl LewisX and proliferating cell nuclear antigen expression in adenocarcinoma and sialyl Lewis(a) and proliferating cell nuclear antigen expression in non-adenocarcinoma may be an important determinant of recurrence.