Sialyl Lewis(x) expression at the invasive front as a predictive marker of liver recurrence in stage II colorectal cancer

Sialyl Lewis(x) (SLX) is a carbohydrate ligand for endothelial selectin that participates in cell adhesion, proliferation and scattering. It plays an important role in cancer cell adhesion to vascular endothelial cells, leading to hematogenous metastasis. The prognostic significance of SLX expression level at the invasive front in patients with stage II colorectal cancer (CRC) was examined. A total of 209 patients with stage II CRC curatively resected between 1997 and 2000 were enrolled. The preoperative serum SLX levels measured by radioimmunoassay and SLX immunoexpression levels at the invasive front, and at the non-invasive frontal region determined by tissue microarray were analyzed. SLX expression at the invasive front was positively associated with tumor invasion depth (P=0.007) and tumor budding grade (P=0.038). Disease-free survival curves differed between the high and low SLX-expression groups (5-year survival rates, 77.0 and 89.7%, respectively; P=0.036). Liver cancer recurrence was more frequent in the high-expression group than in the low-expression group (15.9 and 2.4%; P=0.002). Multivariate analysis revealed that its expression (hazard ratio, 5.26; P=0.015) and venous invasion (hazard ratio, 4.14; P=0.040) were independent predictive markers of liver cancer recurrence. Neither the preoperative serum SLX level nor SLX expression at the non-invasive frontal region showed any association with histopathological features or disease-free survival. SLX expression level at the invasive front is a promising marker for identifying patients with stage II CRC with a high risk of liver cancer recurrence.