Finally, although the iNOS isoform has received most of the attention, the recent literature indicates that the endothelial isoenzyme (eNOS) can also be present in cancer cells, where it can modulate the phenotype of CSCs, as reported for CRC [56] and prostate cancer [64], which adds more complexity to the relationship between NO and cancer. This evidence concerns the gene NOS2 and prostate carcinoma.