Levina et al. [37] demonstrated that the high tumorigenic and metastatic potentials of lung cancer stem cells correlated with superior production of angiogenic factors and growth factors involved in cell proliferation and angiogenesis, describing increased levels of SCGF, stroma-derived factor 1α, and SCF in tumors from cancer stem cells in association with the stem cell phenotype. This evidence concerns the gene KITLG and lung cancer.