Objective: To determine expressions of NKX3.1 mRNA and protein in prostatic tissues and to investigate the relation between homeobox gene NKX3.1 and prostatic carcinoma.
Methods: 76 prostatic tissues (32 cancer, 12 normal prostate and 32 benign prostatic hyperplasia tissues) and 96 non-prostatic tissues were analyzed for the detection of expressions of NKX3.1 mRNA and protein by using semi-quantitative RT-PCR, Western blotting and immunohistochemical technique.
Results: In 76 prostatic tissues, NKX3.1 mRNA was detected in 75 specimens (98.7%), whereas in 96 non-prostatic specimens, NKX3.1 mRNA was negatively expressed in the tissues of bladder, kidney, liver, intestine, fat and skin, except for two expressed in testis and one in mammary gland. The expression ratio of NKX3.1 protein in the epithelia cells of prostate was 100%, but in testis mammary gland was 16.7%, in bladder and intestine was 8.3%, and in kidney, liver, fat and skin was 0% (P < 0.01). The total strong positive ratio of NKX3.1 protein in the epithelia cell of prostate was 94.7%, 5.3% in the stroma cell of prostate (P < 0.01), and 13.6% in benignant prostate cell, 40.6% in prostate cancer (P < 0.01), respectively.
Conclusion: It is suggested that NKX3.1 is not only the prostate-specific homeobox gene, but is the epithelia-cell-specific gene of prostate. It may play an important role in the development of prostatic carcinoma.