['L1, a 200-220 kDa transmembrane glycoprotein of the immunoglobulin superfamily, has been shown to affect prognosis of various types of cancer and was shown to enhance peritoneal metastasis in ovarian cancer in vivo.', 'Immunostaining with anti-L1 antibody was performed with 72 surgically resected pT3-stage gastric cancer specimens. Correlation of immunoreactivity with clinicopathological variables was evaluated and survival curves were compared between L1-positive and negative cases.', 'L1 was detected in 15 specimens (21%), more often among the intestinal-type cancer. No correlation was observed between L1 expression and presence of free cancer cells in the peritoneal cavity or development of peritoneal carcinomatosis during the follow-up. Nevertheless, prognosis of patients with L1-positive cancer was significantly inferior (p=0.024), particularly among the diffuse-type cancer cases.'] Is expression of L1 cell adhesion molecule a significant prognostic factor in pT3-stage gastric cancer?