The diagnostic value of prostatic specific membrane antigen mRNA in detecting prostate cancer pelvic lymph nodes micrometastasis after neoadjuvant hormonal therapy

Objective To explore the evaluation of prostatic specific membrane antigen (PSMA)mRNA in detecting prostate cancer pelvic lymph nodes micrometastasis after neoadjuvant hormonal therapy (NHT).Methods Fifty-four patients of T2c-T3a prostate cancer were divided into positive pathology group,positive micrometastasis group,negative micrometastasis group.Six female cases who accepted radical cystectomy due to bladder cancer were as control group.Pedal lymphangiography was performed.NHT were administrated for 3 months in patients without lymph nodes metastasis.The level of prostate specific antigen (PSA) mRNA and PSMA mRNA in lymph fluid of the suspectable lymph nodes under the X-ray fluoroscope before radical prostatectomy(RP) were detected by quantitative real-time polymerase chain reaction PCR and compared.Furthermore,the lymph nodes pathology and immunohistology results were compared.Results Positive pathology group included 6 patients and 11 lymph nodes occurred metastasis in 14 lymph nodes.The expression of PSA mRNA and PSMA mRNA were positive.Positive micrometastasis group included 12patients,and had no lymph nodes metastasis in 31 lymph nodes.But the expression of PSA mRNA and PSMA mRNA were positive in 27 lymph nodes and negatively in 4 lymph nodes.Negative micrometastasis group included 36 patients and the expression of PSA mRNA and PSMA mRNA in 111 lymph nodes were negative.The level of PSA mRNA between preoperative lymph fluid and postoperative lymph nodes in positive pathology group and positive micrometastasis group had significant difference (0.3343 ± 0.0288 vs.0.2097 ±0.0235,0.2872 ±0.0291 vs.0.1770 ±0.0222,P ＜0.05).But the level of PSMA mRNA in positively pathology group and positive micrometastasis group had no significant difference (0.6815 ± 0.0621vs.0.6319 ± 0.0331,0.6672 ± 0.0673 vs.0.6106 ± 0.0916,P ＞ 0.05).The level of PSA mRNA and PSMAmRNA between preoperative lymph fluid and postoperative lymph nodes in negative micrometastasis group and control group had no significant difference(negative micrometastasis group:0.0154 ± 0.0015 vs.0.0506 ±0.0034,0.0148 ± 0.0054 vs.0.0516 ± 0.0058 ;control group:0.0129 ± 0.0015 vs.0.0468 ± 0.0033,0.0160 ±0.0003 vs.0.0499 ± 0.0009,P ＞ 0.05).The level of PSA mRNA and PSMA mRNA between preoperative lymph fluid and postoperative lymph nodes in positive pathology group and positive micrometastasis group had significant difference compared with negative micrometastasis group and control group (P ＜ 0.05).The level of PSMA mRNA in preoperative lymph fluid and postoperative lymph nodes in positive micrometastasis group had significant difference (P ＜ 0.05).Conclusions Although residual foci of atrophic prostate cancer cells in resected lymph nodes after NHT can be difficult to be diagnosed by pathological examination.The present results show the usefulness of quantitative real-time PCR targeting PSA and PSMA genes for detected micrometastatic tumour foci in pelvic lymph nodes from fine needle aspiration biopsy of lymph nodes before radical prostatectomy.The PSA mRNA and PSMA mRNA expression of the lymph fluid is preferred to diagnose the exist of lymph nodes micrometastasis after NHT.PSMA mRNA can be the best biomarker for early detection pelvic lymph nodes micrometastasis.This may provide the reliable diagnostic evidence for clinical stage before radical prostatectomy. Key words: Prostate neoplasms;  Radical prostatectomy;  Lymph nodes;  Micrometastasis