Cytotoxicity of activated natural killer cells and expression of adhesion molecules in small-cell lung cancer

Background/Aim: Although small-cell lung cancer (SCLC) is sensitive to anticancer agents, most patients with SCLC experience relapse and die within two years. Here, we examined the relationship between natural killer (NK) cells and adhesion molecules on SCLC cell lines. Materials and Methods: The expression levels of HLA class I, β2-microglobulin, Fas/Apo-1 receptor (FAS) and adhesion molecules on SCLC cell lines were examined by flow cytometry. The cytotoxicity of activated NK cells from SCLC patients was examined using ⁵¹Cr-release assay. Results: HLA class I antigen and β2-microglobulin expression levels in SCLC cell lines were lower than those in healthy volunteers. SCLC cell lines were susceptible to lysis by activated NK cells but this showed no correlation with expression levels of adhesion molecules. Conclusion: Target cell susceptibility to activated NK cells from five SCLC patients correlated with survival benefit; target cell susceptibility to activated NK cells may be a surrogate marker of outcome for patients with SCLC.