gms | German Medical Science

Introduction: Recently, the activated leukocyte cell adhesion molecule (ALCAM, CD166) was identified as an inert cancer stem cell marker for non-small cell lung cancer (NSCLC). Few data exist regarding the clinical relevance of CD166 expression in NSCLC.

Material and methods: Here, we evaluate the expression of CD166 using immunohistochemistry (clone MOG/07) in a large cohort of NSCLC patients (n=1910) on a tissue microarray basis. Results were correlated with clinical, histopathological, and patient survival data (Chi-square-test, t-test, Kaplan-Meier analysis, log-rank test, respectively). Multivariate analysis was also performed (Cox-regression).

Results: We found that CD166 is expressed in a large fraction of NSCLC (39%) and the expression is inversely associated with tumor size (p=0.041) and lymph node status (p=0.040). Tumor grading slightly failed to be significantly inverse associated with CD166 expression (p=0.054). Kaplan-Meier survival analysis revealed no significant overall survival benefit in the group of CD166-positive patients (p=0.099).

Conclusion: Due to the results of the present study, the theory of an ‘inert surface marker’ must be questioned. The association of CD166 with smaller tumors and no lymph node metastases does not make it a typical cancer stem cell marker. Further studies are required investigating the functional role of CD166 in NSCLC.