The flow cytometry analysis revealed that the lung cancer cells consist of a heterogeneous population with different phenotypes (CD166+/CD44+, CD166+/CD44−, CD166−/CD44+, CD166−/CD44−, CD166+/EpCAM+, CD166+/EpCAM−, CD166−/EpCAM+, and CD166−/EpCAM−), which supports the initial hypothesis that the CSCs population is heterogeneous. The gene discussed is CD44; the disease is lung cancer.