NK3 Homeobox1 (NKX3-1) is a homeobox-containing transcription factor, which binds preferentially the consensus sequence 5’-TAAGT[AG]-3’ and may act as a transcriptional repressor. The NKX3-1 transcription factor functions as a negative regulator of epithelial cell growth in prostate tissue. NKX3-1 has an imperative role in normal prostate development, regulating proliferation of glandular epithelium and in the formation of ducts in prostate. In addition, NKX3-1 functions as a tumor suppressor controlling prostate carcinogenesis, as shown by its ability to inhibit proliferation and invasion activities of PC-3 prostate cancer cells. Abnormal expression of NKX3-1 is linked with prostate tumor progression.