The prognostic roles of circulating ALDH1(+) tumor cell in the patients with non-small cell lung cancer

Circulating tumor cells can provide important diagnostic and prognostic information of the patients with non-small cell lung cancer (NSCLC). Aldehyde dehydrogenase 1 (ALDH1), a cancer stem cell marker, has been used in various tumors, including NSCLC. In the present study, we isolated the circulating ALDH1(+) tumor cells from the NSCLC patients using ALDH1 as a potential marker. Higher percentage of ALDH1(+) tumor cells was identified in blood samples from the NSCLC patients compared with normal controls. ALDH1(+) cells were correlated with the poor prognosis of these patients by using Kaplan–Meier analysis. In the last, the tumorigenic properties of ALDH1(+) tumor cells were determined in vitro and in vivo by using sphere assay and xenograft tumor mouse models. Our in vitro and in vivo experiments demonstrated that ALDH1 could drive the stemness of circulating NSCLC cells. Circulating ALDH1(+) cells could be used as a prognostic marker for NSCLC.