['D2-40 staining has been reported to be useful for both identifying lymphatic vessel invasion (LVI) and counting lymphatic vessel density (LVD) in various cancers. The aim of this study was to clarify the prognostic significance of D2-40 staining in patients with esophageal squamous cell carcinoma (ESCC).', 'A total of 159 consecutive patients with ESCC who underwent an esophagectomy with lymph node dissection were eligible. LVI was diagnosed by both hematoxylin-eosin (LVI-HE) and D2-40 staining (LVI-D2-40) in the largest central sections of the entire tumors, while both the intratumoral and peritumoral LVD were counted by D2-40 staining. The correlation between the prognosis and clinicopathological factors was investigated.', "An univariate analysis revealed that tumor invasion beyond the muscularis propria, lymph node metastasis (LNM), LVI-HE, LVI-D2-40, high intratumoral LVD, and blood vessel invasion correlated with worse patients' prognosis (P\u2009<\u20090.05). A multivariate analysis revealed LNM to be the only independent prognostic factor in all cases (P\u2009=\u20090.0083). On the other hand, when the prognostic factors of 83 patients without LNM were investigated, LVI-D2-40 was revealed to be the only independent prognostic factor (P\u2009=\u20090.048)."] Is lymphatic vessel invasion detected by the D2-40 monoclonal antibody an independent prognostic factor in node-negative esophageal squamous cell carcinoma?