Expression And Clinical Significance Of Id 1 MRNA And Id 1 Protein In Prostate Cancer

Objective: It has been proved recently that Id 1 (inhibitor of differentiation or inhibitor of DNA binding) is related to tumorigenesis, invasion and metastasis in some cancers. This study was to explore the expression of Id 1 protein and Id 1 mRNA in human prostate cancer (PCa), and to analysis its potential usage in clinical.Method: The quantity of Id 1 mRNA relative to P-actin was detected by SYBR Green I-based Real Time PCR in prostatectomy or biopsy samples of 2 human normal prostate, 18 benign prostate hyperplasia (BPH) and 38 prostate cancer. The relationship between the relative quantity of Id 1 mRNA and some clinicopathological parameters, such as Gleason score, prostate specific antigen(PSA) and clinical stage, was further analysised;By SP immunohistochemistry, the expression of Id 1 protein were detected in paraffin section specimens of 43 prostate cancer cases, 12 benign prostate hyperplasia (BPH) cases and 2 normal prostate.Results: In prostate cancer tissues, the relative quantity of Id 1 mRNA was obviously higher than that in BPH(P<0.001). The expression of Id 1 mRNA was negative correlated with Gleason score in prostate cancer group(r=0. 9995, P<0. 05). The mean quantity of Id 1 mRNA in the patients whose PSA were more than 10mg/L, was significantly increased (P<0.01). After therapeutic prostatectomy one to two years, the probability of infiltration and relapse was obviously higher in the patients whose Id 1 mRNA expression were markedly up-regulation;There were no Id 1 expression in normal prostate tissue, and negative to weak expression of Id 1 in BPH (5/12) .In contrast, most of PC (43/43) tissues showed moderate to high positive Id 1 expression, which was significantly.higher than that of BPH (P<0.01 = . Furthermore, Id 1 overexpression was correlated with the increasing of Gleason grade (spearman correlation: r_S=0.63 P< 0.01 =.Conclusion: The expression of Id 1 mRNA is significantly increased in prostate cancer, and it has positive correlation with the differentiation level of prostate cancer. The higher expression of Id 1 mRNA reflected its relationship with the progression of prostate cancer on the level of transcription. In prostate cancer, Id 1 protein is Over expression andthe level of Id 1 expression is correlated with Gleason grade, suggesting that Id 1 is associated with prostate tumor malignancy. Id 1 might be used as a new marker of PC for prognosis.