To further the understanding towards a clear relationship among compounds’ property, binding profile and effect on the NOS enzyme, and to promote the design of isoform-selective NOS interactors to treat inflammation, arthritis, stroke, septic shock, neurodegenerative disorders, cardiovascular disorders and cancer, a systematic analysis on the available structures of human eNOS, nNOS and iNOS, is carried out in this study. This evidence concerns the gene NOS1 and cancer.