Expression of stromal cell-derived factor-1α is an independent risk factor for lymph node metastasis in early gastric cancer.

Lymph node metastasis is considered to be a significant prognostic factor for early gastric cancer (EGC). However, no real consensus exists on which patient and/or tumor characteristics are associated with lymph node metastasis. We investigated whether stromal cell-derived factor (SDF)-1α expression correlates with lymph node metastasis in patients with EGC by immunohistochemically examining the expression of SDF-1α in 138 archival tissue specimens of EGC. Of these specimens, 59 (42.8%) and 79 (57.2%) were grouped into SDF-1α-positive and SDF-1α-negative groups, respectively. No significant differences existed with respect to age, gender, tumor location, proportion of tumors >20 mm in size, macroscopic type, depth of invasion or histology between the SDF-1α-positive and -negative groups. However, the SDF-1α-positive group was significantly correlated with lymphovascular invasion and lymph node metastasis. Results of the univariate analyses indicated that lymphovascular invasion, undifferentiated histology and SDF-1α positivity were statistically significant risk factors affecting lymph node metastasis in patients with EGC. Multivariate analyses showed that lymphovascular invasion [hazard ratio (HR), 8.595; 95% confidence interval (CI), 1.694-43.595; P=0.009], undifferentiated histology (HR, 2.965; 95% CI, 1.037-8.471; P=0.043) and SDF-1α positivity (HR, 2.108; 95% CI, 1.316-10.135; P=0.013) were independent risk factors predicting lymph node metastasis in EGC. In conclusion, these results suggest that SDF-1α expression in tumor cells is a predictive marker of lymph node metastasis in EGC.