Stem cell factor and granulocyte-macrophage-colony stimulating factor as candidates for tumour markers for non-small-cell lung cancer.

We have investigated the serum level of stem cell factor (SCF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) in relation to a control group and commonly accepted tumour markers, such as carcinoembryonic antigen (CEA) and cytokeratin fragment 19 (CYFRA 21-1). Additionally, we have defined the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and receiver-operating characteristics (ROC) curve of SCF and GM-CSF in non-small-cell lung cancer (NSCLC). The serum levels of cytokines were measured in 50 patients with NSCLC and in 20 healthy subjects. SCF and GM-CSF were determined using enzyme-linked immunosorbent assay (ELISA), CYFRA 21-1 was measured by radioimmunoassay and CEA by microparticle enzyme immunoassay. There were significant increases in circulating SCF and GM-CSF in the lung cancer patients compared to the control group. The diagnostic sensitivity of GM-CSF was higher (70%) than the sensitivity of CEA (62%) and CYFRA 21-1 (51%). The diagnostic specificity of GM-CSF was lower (65%) than SCF specificity (70%), but the GM-CSF predictive values were higher in relation to the predictive values of SCF. These results suggest a potential role of SCF and GM-CSF as tumour markers for NSCLC.