The clinical significance of the tumor cell D2-40 immunoreactivity in non-small cell lung cancer

BackgroundA monoclonal antibody D2-40 has been widely used for tumor lymphangiogenesis and lymphatic vessel invasion (LVI) in human cancers. However, the clinical significance of the tumor cell D2-40 immunoreactivity has not been clearly understood.Patients and methodsWe evaluated the tumor cell D2-40 immunoreactivity in non-small cell lung cancer (NSCLC). One hundred and forty-seven NSCLC patients were investigated. Immunohistochemistry using D2-40 was performed to evaluate the tumor cell D2-40 immunoreactivity, micro-lymphatic vessel density (Micro-LVD) and LVI. The intratumoral microvessels density (MVD) was evaluated by the CD34-immunostaining, and tumor proliferation was evaluated by the Ki-67-immunostaining.ResultsThe percentage of D2-40-positive tumor cells was significantly higher in squamous cell carcinomas than in adenocarcinomas (P < 0.0001), and all D2-40-strong tumors were squamous cell carcinomas. The percentage of D2-40-strong tumors was significantly higher in moderately to poorly differentiated tumors than in well-differentiated tumors (P = 0.0332). Furthermore, the Ki-67 proliferation index in D2-40-strong tumors was significantly the highest. However, the tumor cell D2-40 immunoreactivity was not associated with Micro-LVD, LVI, or MVD. Regarding the patient survival, the overall survival was significantly lower in patients with D2-40-strong tumors than in patients with D2-40-negative or D2-40-weak tumors (P = 0.0005). Multivariate analyses also revealed the tumor cell D2-40 immunoreactivity to be a significant prognostic factor of poor prognosis for NSCLC patients (P = 0.0007).ConclusionThe D2-40 immunostaining is useful to identify aggressive squamous cell carcinomas of the lung.