Studies on breast cancer, prostate cancer, glioma, and melanoma have identified that these cancers typically express high levels of DDAH1 and are dependent on DDAH/ADMA/NO signaling for cell survival, proliferation, migration, and/or angiogenesis; these cancers would be prime candidates for treatment by DDAH1 inhibition. Here, DDAH1 is linked to Familial prostate cancer.