CD40 expression on human lung cancer correlates with metastatic spread

Purpose: The poor prognosis associated with lung cancer is related to the high incidence of regional and distant metastasis. There is a crucial need to identify parameters that can predict a tendancy to metastatic spread to allow better prognostic evaluation and therapeutic approach. Methods: Using flow cytometry we evaluated 18 human lung cancer cell lines for the expression of different surface markers on lung cancers suggested to be possible prognostic parameters, including epidermal growth factor receptor (EGFR), intercellular adhesion molecule 1 (ICAM-1), Fas and CD40. Results: No correlation was found between tumor prognosis and EGFR, ICAM-1 or Fas. However, a statistically significant correlation was found between the surface expression of CD40 and the metastatic spread of the tumor. In this study, 14 of 18 lung cancer cell lines (78%) expressed CD40 on their surface. All of the 4 tumors that were CD40-negative, were stage I tumors, without any evidence of regional or distant metastasis. Of the 14 tumors that expressed CD40, all but 1 (93%) had either nodal or systemic metastasis at the time of diagnosis. Patients whose tumors were CD40-negative showed a significantly better N stage, overall stage at presentation and survival than those patients with CD40-positive patients. No significant differences between the two groups were observed in tumor size, gender, age, histology, differentiation or preoperative therapy. Conclusions: These results suggest that CD40 expression on lung cancer may play a role in metastatic spread, and also may serve as a prognostic marker and an indicator of advanced disease.