Spheroids (cancer stem cells) derived from the 786-O cell line (renal carcinoma) have been described [44] CeCa (cervical cancer) [45], H3122 (non-small-cell lung cancer) [24], and A549 (lung cancer) [24] exhibit an elevated level of the CD73 protein compared to the cell line from which they are derived. This evidence concerns the gene NT5E and lung cancer.