Aneuploidy and rapid cell proliferation in recurrent prostate cancers with androgen receptor gene amplification

Mechanisms of prostate cancer recurrence during androgen deprivation are poorly understood. We recently described androgen receptor (AR) gene amplification in 28% of recurrent prostate carcinomas from hormone-refractory prostate cancer patients. To investigate the hypothesis that amplification of the AR gene promotes the growth of hormone-refractory prostate carcinomas, DNA flow cytometric (FCM) studies were carried out to compare matched, primary and hormone-refractory recurrent samples from 31 prostate cancer patients. Recurrent tumours had a higher (P=0.05) S-phase fraction (SPF) (10.6+/-4.6) than corresponding primary tumours from the same patients (7.0+/-4.1) and the frequency of aneuploidy also increased from 8-55%. Recurrent tumours with AR gene amplification had a significantly higher (P=0.02) SPF (14.0+/-6.5) than those with no amplification (9.0+/-2.9). The results suggest that clinical progression of prostate cancer during androgen withdrawal therapy is often associated with increased cell proliferation rate and formation of DNA aneuploidy. AR amplification may be an important molecular mechanism underlying the increase in proliferation rate of some recurrent tumours.     

Expression of ERalpha and ERbeta in prostate cancer

BACKGROUND: It has been suggested that estrogens and their receptors (ERs) may be involved in the development and progression of prostate cancer. To elucidate the significance of these receptors, expression of both ERalpha and ERbeta was measured in benign and malignant prostate tumors, as well as in cell lines. METHODS: Expression of ERalpha and ERbeta was measured in prostate hyperplasia (BPH, n = 7), androgen-dependent (n = 30) as well as hormone-refractory (n = 12) prostate carcinomas, and in four prostate cancer cell lines (LNCaP, DU145, PC-3, and 22Rv1) using real-time quantitative RT-PCR. RESULTS: Only low-level expression of ERalpha was found in all tumor types and cell lines. The level of expression was similar to that observed in breast carcinomas found to be negative for ERalpha by immunohistochemistry. All cell lines showed low, but detectable, levels of ERbeta expression. The mean expression of ERbeta in the hormone-refractory carcinomas was about half that seen in BPH or the androgen-dependent carcinomas; however, the difference was not statistically significant. CONCLUSIONS: The data suggest it is unlikely that alterations in the expression of either ER are commonly involved in the progression of prostate cancer.     

Hormone-resistant prostate cancer with symptomatic pelvic tumours: patient survival and prognostic factors

OBJECTIVES: To determine the survival and investigate the prognostic significance of immunohistochemical variables and clinical factors in patients with hormone-resistant prostate cancer (HRPC) and symptomatic pelvic tumours, in whom preliminary observations indicated that survival exceeded the median 8-10 months of patients with HRPC and painful bone metastases. PATIENTS AND METHODS: Seventy-five patients with HRPC referred for palliative pelvic radiotherapy between 1980 and 1996 were identified. For all patients at least two prostate biopsies had been obtained, one before primary hormone treatment and at least one after clinical progression despite androgen deprivation (HRPC biopsy). Bone scans at the time of referral were assessed. The medical records were reviewed for clinical variables of possible prognostic significance. Histological grade was recorded, and prostate-specific antigen (PSA), androgen receptors (ARs), Ki-67 and p53 determined immunohistochemically. In 18 HRPC specimens the degree of AR amplification was analysed. RESULTS: Positive staining for ARs was high in the HRPC biopsies, although there was no association with AR amplification. Ki-67 positivity increased after the development of HRPC. The median (range) survival was 14 (1-141) months; age < 65 years was associated with increased survival. In a multivariate analysis the following variables remained independent prognostic factors for survival from the time of the HRPC biopsy: bone metastases (0-10 vs > 10 lesions, P < 0.001), low Ki-67 score (0 vs 1-3, P = 0.006) and low p53 positivity score (0 vs 1-3, P = 0.014) in the HRPC biopsy. CONCLUSIONS: The median survival of patients with HRPC and pelvic tumours requiring palliation seems to exceed that of patients with HRPC and dominating painful bone metastases by at least 4-6 months. Simple clinical (bone metastases) and immunohistochemical variables (Ki-67, p53) enable patients with particularly long survival times to be identified, and in whom palliative treatment needs to be improved.     

High level of androgen receptor is associated with aggressive clinicopathologic features and decreased biochemical recurrence-free survival in prostate: cancer patients treated with radical prostatectomy

BACKGROUND: Prostate cancer (PCa) is androgen dependent and is regulated by androgen/androgen receptor (AR) signaling pathway. However, the clinical significance of AR is in question. In this regard, we have correlated levels of AR expression with some well-established clinical and pathologic parameters and assessed the prognostic value of AR expression in PCa patients treated with radical prostatectomy. DESIGN: A total of 640 cases treated with radical prostatectomy were used to build tissue microarrays. Normal prostate tissue, benign prostatic hyperplasia, and index tumor were cored in triplicate (0.6 mm). An array (2 mm) of 177 metastatic PCa was built as well. Slides were immunostained with an antibody to AR and Ki-67 and digitized. Correlations between AR expression and clinicopathologic variables were analyzed by the Spearman test. Biochemical recurrence-free survival analysis was performed using Kaplan-Meier analysis, and Cox proportional hazard regression was used to determine the probability of disease recurrence. RESULTS: AR was found in epithelial nuclei of both benign and cancer tissues. AR index was higher in normal prostate tissues than that in PCa and benign prostatic hyperplasia and decreased in metastases than PCa. High level of AR expression was correlated with clinical stage, lymph node status, extracapsular extension, seminal vesicle invasion, and Gleason score. High levels of AR status also correlated with high Ki-67 index (r = 0.211, P = 0.0000). By Kaplan-Meier actuarial model, high expression of AR was predictive of a higher probability of recurrence (P = 0.0046, hazards ratio 2.72 [confidence interval 1.28-4.011]). By multivariate analysis, a high level of AR expression was an independent prognostic indicator of biochemical recurrence-free survival (P = 0.0042; hazards ratio 2.422 [confidence interval 1.32-4.44]). CONCLUSIONS: High levels of AR are associated with increased proliferation, markers of aggressive disease and are predictive of decreased biochemical recurrence-free survival independently. This confirms the role of AR in tumor growth and progression in hormonally naive PCa.     

Fluorescence in situ hybridization evaluation of c-myc and androgen receptor gene amplification and chromosomal anomalies in prostate cancer in Japanese patients

BACKGROUND: Oncogene amplification and chromosomal anomalies are found in many solid tumors and are often associated with aggressiveness of cancer. We evaluated the frequency and the association of c-myc and androgen receptor (AR) gene amplification and gain of chromosome 8 or X in prostate cancer in Japanese patients. METHODS: We examined a total of 42 prostate cancer specimens, using fluorescence in situ hybridization (FISH). Dual-labeling hybridization with a directly labeled centromere probe for chromosome 8 or X together with a probe for the c-myc or AR locus was performed. RESULTS: Gain of chromosome 8 was identified in 54.8% of specimens and was associated with Gleason sum and nuclear anaplasia in untreated prostate cancers. c-myc gene amplification was found in 14.3% of specimens. Gain of chromosome X was identified in 42.9% of specimens. AR gene amplification was detected in 0 of 37 untreated prostate cancers, but in 1 of 5 hormone-refractory prostate cancers. CONCLUSIONS: Our results suggest that c-myc and AR gene amplification and gain of chromosome 8 or X may be associated with the development and progression of prostate cancers. These results obtained in Japanese cases are consistent with the results observed in prostate cancer in Western countries.     

组织激肽释放酶基因7在前列腺癌组织中的表达

目的 探讨组织激肽释放酶基因7(KLK7)在不同前列腺组织中的表达情况.方法运用逆转录聚合酶链反应法检测正常前列腺(5例)、良性前列腺增生(BPH)及BPH细胞株(BPH1,13例)、前列腺癌及前列腺癌细胞株(8例)的上皮细胞中KLK7mRNA表达水平;蛋白质印迹法检测不同前列腺组织上皮细胞中KLK7蛋白表达水平;免疫组化分析正常前列腺(20例)、BPH(50例)、前列腺癌(103例)组织中KLK表达水平.根据染色强度分为4个等级(-,+,++,+++)进行半定量分析,染色强度++及+++者判定为阳性.结果 正常组、BPH组和前列腺癌组KLK7 mRNA表达相对值分别为0.59、0.52、0.02,组间比较差异有统计学意义(F=13.03,P＜0.01),前列腺癌上皮中KLK7 mRNA表达下调(P＜0.01),正常前列腺和BPH上皮中KLK7 mRNA表达差异无统计学意义(P＞0.05).KLK7蛋白在正常前列腺、增生前列腺、DU145、LNCaP、PC3、22RV1、BPH细胞株中表达水平相对值分别为0.22、0.40、0.01、0.05、0、0.03、0.14.免疫组化染色结果 显示正常前列腺组织、BPH组织、前列腺癌中KLK7蛋白表达阳性率分别为65.0%(13/20)、76.0%(38/50)、17.5%(18/103),前列腺癌组与前2组比较差异均有统计学意义(P＜0.01),前2组间比较差异无统计学意义(P＞0.05).结论 KLK7在前列腺癌组织中表达下调,提示KLK7在前列癌的发生和进展中可能起一定作用.     

Flap endonuclease 1 is overexpressed in prostate cancer and is associated with a high Gleason score

OBJECTIVE: To investigate the expression and potential clinical usefulness of structure-specific flap endonuclease 1 (FEN-1) in human primary prostate cancer using tissue microarray technology, as FEN-1 was recently identified to be overexpressed in CL1.1, the most aggressive clone generated from the hormone-refractory prostate cancer cell line CL1. MATERIALS AND METHODS: Immunohistochemistry was performed on tissue microarrays constructed from paraffin-embedded specimens of primary prostate cancer from 246 patients who had had a radical prostatectomy. Prostatic intraepithelial neoplasia (PIN), benign prostatic hyperplasia (BPH) and normal prostate epithelium were represented on the array. FEN-1 nuclear expression was scored based on the percentage of target cells staining positively, and correlated with Gleason score, preoperative prostate-specific antigen (PSA) level and pathological stage. The time to PSA recurrence was also analysed. RESULTS: The mean expression of FEN-1 was significantly higher in cancer (36.7%) than in normal (13.2%), BPH (4.5%) and PIN (15.4%) specimens (P < 0.001). FEN-1 expression was significantly correlated with Gleason score (ó = 0.23, P = 0.002). A higher preoperative serum PSA level (P = 0.015), Gleason score > or = 7 (P < 0.001), seminal vesicle invasion (P < 0.001) and capsular involvement (P = 0.004) were associated with PSA recurrence, whereas FEN-1 expression was not. In a multivariate analysis, only Gleason score > or = 7 (P < 0.001), seminal vesicle invasion (P = 0.005) and capsular involvement (P = 0.009) were retained as independent predictors for PSA recurrence. CONCLUSIONS: FEN-1 is overexpressed in prostate cancer compared with matched normal prostate, and its expression increases with tumour dedifferentiation, as shown by increasing Gleason score. These results suggest that FEN-1 might be a potential marker for selecting patients at high risk, and a potential target for prostate cancer diagnosis and therapy.     

前列腺癌组织中TRIB1基因和蛋白异常表达与患者不良预后的相关性

目的研究Tribbles同源蛋白1(TRIB1)在良性前列腺增生和前列腺癌中的表达,并分析其表达水平与患者临床特征及预后的关系。方法在公共基因芯片数据库(GEO)中下载前列腺样本中的相关基因芯片数据,分析TRIB1在前列腺样本中mRNA的表达水平。收集临床手术切除或者穿刺活检的前列腺癌和前列腺增生组织,通过免疫组化检测前列腺癌、前列腺增生组织中TRIB1蛋白的表达。分析TRIB1蛋白和基因的表达水平与患者临床特征及预后的关系。结果前列腺癌患者组织中TRIB1蛋白表达显著上调(P0.01),TRIB1蛋白表达上调与前列腺癌Gleason评分(P0.01)、病理分期(P=0.02)相关,基因芯片数据提示TRIB1基因表达上调与前列腺癌Gleason评分(P=0.02)、病理分期(P=0.01)、无生化复发生存率(BCR-free survival)(P=0.047)相关。结论 TRIB1在前列腺癌组织中表达上调,前列腺组织中检测TRIB1可能有助于判断前列腺癌分化程度并评估预后。     

Involvement of decreased Galectin-3 expression in the pathogenesis and progression of prostate cancer

BACKGROUND: Altered expression or loss of function of Galectin-3 (Gal-3) was suggested to be involved in the pathogenesis and progression of various human cancer entities. The aim of the present study is to determine the expression of Gal-3 in prostate tissue emerging from a benign to a malignant, in the beginning hormone-sensitive and finally hormone-refractory status to further elucidate the role of this carbohydrate-binding protein for the pathogenesis and/or progression of malignant prostatic disease. MATERIALS AND METHODS: Five hundred and eighty three tissue samples from malignant, tumor adjacent benign, and histologically benign intra-prostatic areas, retrieved out of 25 whole mounted prostate cancer (CaP) specimens and additional 95 samples of hormone-refractory CaP, were processed to tissue microarrays. Immunohistochemical Gal-3 expression was correlated with clinicopathological parameters among the different tissue entities. RESULTS: Gal-3 expression was significantly decreased in the hormone-sensitive CaP specimens when compared with the respective benign tissue either localized far distant from the malignant lesion (P < 0.0001, Wilcoxon test) or directly neighboring the primary tumor (P < 0.0001). The staining reaction in the benign tissue areas directly neighboring the primary cancerous lesions differed significantly from the benign glands localized distant from the primary tumors (P < 0.001). A statistically highly significant, almost complete loss of Gal-3 was observed in the hormone-refractory when compared with the hormone-sensitive tumors (P < 0.0001; mean staining score: 27.7% vs. 8.5%). CONCLUSIONS: The present investigation clearly indicates decreased expression of Gal-3 to be substantially involved in the pathogenesis and further progression of CaP from benign prostate glands to a finally hormone-refractory malignant disease.     

The androgen receptor in hormone-refractory prostate cancer

Advanced prostate cancer is responsive to hormone therapy that interferes with androgen receptor （AR） signalling. However, the effect is short-lived, as nearly all tumours progress to a hormone-refractory （HR） state, a lethal stage of the disease. Intuitively, the AR should not be involved because hormone therapy that blocks or reduces AR activity is not effective in treating HR tumours. However, there is still a consensus that AR plays an essential role in HR prostate cancer （HRPC） because AR signalling is still functional in HR tumours. AR signalling can be activated in HR tumours through several mechanisms. First, activation of intracellular signal transduction pathways can sensitize the AR to castrate levels of androgens. Also, mutations in the AR can change AR ligand specificity, thereby allowing it to be activated by non-steroids or anti-androgens. Finally, overexpression of the wild-type AR sensitizes itself to low concentrations of androgens. Therefore, drugs targeting AR signalling could still be effective in treating HRPC.     

Current Topics in the Treatment of Hormone-Refractory Prostate Cancer

Following endocrine therapy, progression to a hormone-refractory state is inevitable in patients with locally advanced or metastatic prostate cancer, if they survive competing mortality. Current treatment options are essentially palliative, with the aim of maintaining quality of life and prolonging survival.Following the failure of primary androgen ablation, a number of treatment strategies are available. Exploitation of the anti-androgen withdrawal syndrome and further hormonal therapies are well-established treatments. More recently, interest in chemotherapy has been renewed owing to demonstrable benefits in prostate specific antigen (PSA) response and pain palliation, albeit without any improvements in survival.However, future treatment options that can prolong survival and maintain quality of life for patients with hormone-refractory prostate cancer (HRPC) are constantly being sought. An increased understanding of the molecular biology of prostate cancer has led to the identification of novel targets and agents. The evaluation of these, and possible addition of them to our armamentarium against prostate cancer, is the goal of ongoing clinical trials.     

Comparison of serum HER2/neu with immunohistochemical HER2/neu expression for the prediction of biochemical progression in metastatic prostate cancer

Objectives:   To examine whether pretreatment serum human epidermal growth factor receptor 2 (HER2/neu) and immunohistochemical HER2/neu expression predict biochemical recurrence-free survival in advanced prostate cancer.
Methods:   We studied 75 untreated patients with metastatic prostate cancer and compared them to a control group of 97 patients without histologically diagnosed prostate cancer. Serum samples were collected for HER2/neu protein analysis before the patients started endocrine therapy. HER2/neu expression in the prostate tissue was evaluated using immunohistochemical analysis.
Results:   Serum concentration of HER2/neu in patients with prostate cancer was significantly higher than in those without cancer ( P  = 0.005). Based on the median HER2/neu value, a cut-off level of 12.5 ng/mL was established to separate low from high serum HER2/neu levels. The biochemical recurrence-free survival rate was significantly lower in patients with a high serum HER2 level ( P  < 0.001). HER2/neu overexpression was found in 18 patients (24%) by immunohistochemical analysis. Biochemical recurrence-free survival rates did not show a statistically significant difference between HER2/neu positive and negative groups. Multivariate analysis showed that the pretreatment serum HER2/neu value was an independent predictor of biochemical recurrence ( P  = 0.02).
Conclusions:   Pretreatment serum HER2/neu may represent a more valuable tool than immunohistochemical HER2/neu expression for the prediction of biochemical recurrence in metastatic prostate cancer patients.     

Role of Chemotherapy in Nonmetastatic Hormone-Refractory Prostate Cancer

ContextDocetaxel chemotherapy has become the standard first-line treatment for metastatic hormone-refractory prostate cancer (HRPC). Nowadays, one of the goals of research is to determine optimal management strategies for different patient populations with prostate cancer.ObjectiveBecause the utility of docetaxel in patients with nonmetastatic HRPC has not yet been evaluated, one of the most challenging questions is to define the role of chemotherapy in nonmetastatic HRPC.Evidence acquisitionIn a recently published subset analysis of TAX-327, a multivariate prognostic model incorporating prostate-specific antigen (PSA) kinetics has been developed to predict survival at 1, 2, and 5 yr in men with metastatic HRPC treated with chemotherapy. This novel model includes PSA doubling time (PSA DT), baseline pain, baseline PSA level, age, type of progression at baseline (measurable disease or bone scan compared with PSA only), presence of liver metastases, and the number of metastatic disease sites.Evidence synthesisThe authors found a statistically significantly better overall survival in patients with PSA ≤114 ng/ml and PSA DT >55 d. Patients with a PSA DT of <55 d had a worse prognosis than patients with a longer PSA DT.ConclusionsBased on these findings, it seems clear nowadays that evaluation of PSA kinetics can help us to delineate the potential benefits of the early indication of chemotherapy. It could be hypothesized that docetaxel-based chemotherapy could have a role in those patients with nonmetastatic HRPC who have a very short PSA DT.     

Expression and somatic mutation on androgen receptor gene in prostate cancer

BACKGROUND: Lack of androgen receptor (AR) expression or mutation on the AR gene creates the tendency for androgen independence and progression of prostate cancer. However, the association between the progression and AR expression or mutations is still controversial. In this study, we evaluated the prognostic significance of AR expression and mutations in prostate cancers. METHODS: Forty-two prostate adenocarcinomas and three lymph node metastatic lesions sampled prior to hormonal therapy were included in this study; AR expression was analyzed immunohistochemically using an antibody against AR and the result was scored as the percentage of AR-positive tumor cells in the total tumor cells. Polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analysis and DNA sequencing were used to detect AR mutations. RESULTS: Our study revealed the average AR expression in the prostate adenocarcinoma was 52.2 +/- 27.1%, which was significantly lower than that in the adjacent non-tumorous prostate tissue (68.3 +/- 18.3% in average) (P < 0.001). A significant correlation was obtained between progression-free survival and AR expression (P < 0.01). By SSCP analysis, three silent mutations (T649T, E709E and E711E) were detected in three separate prostate carcinomas. CONCLUSION: : We conclude that AR expression is a useful prognostic indicator for tumor progression. Androgen receptor mutation may be an uncommon molecular event in untreated prostate cancer in Japanese men.     

前列腺癌组织中ARA55 mRNA表达及临床意义

目的:探讨雄激素受体辅助因子ARA55在前列腺癌组织标本中的表达,分析ARA55 mRNA与患者的临床特征(Gleason评分、临床分期、PSA)之间的相关性。方法:应用实时定量PCR(SYBR染料法)技术,对前列腺癌组织标本中ARA55mRNA表达进行研究。结果:前列腺癌患者标本中ARA55 mRNA均有表达,但表达量有所不同,T1～T2期和T3～T4期Ct值分别为20.57±0.20和16.33±0.31;Gleason评分≤7分和Gleason评分>7分的Ct值分别为23.13±0.13和17.13±0.19;PSA≤10μg/L和PSA>10μg/L的Ct值分别为24.70±0.27和17.21±0.34;内分泌治疗有效和无效的Ct值分别为23.82±0.21和16.71±0.32,前者和后者相比均具有显著的统计学差异(P<0.05)。结论:ARA55 mRNA表达与患者的临床特征(Gleason评分、临床分期、PSA)显著相关,肿瘤分期越早、Gleason评分≤7分、PSA≤10μg/L及内分泌治疗有效的患者其ARA55 mRNA表达量越高。ARA55可能是前列腺癌预后的一个良好预测指标,对于指导前列腺癌内分泌治疗有一定的意义。     

聚集素在前列腺正常、增生、癌组织中的表达及意义

目的　通过检测聚集素 (Clusterin)在前列腺正常、增生、癌变组织中的表达 ,探讨其与前列腺疾病发生发展的关系。　方法　采用免疫组织化学染色法检测 12例正常前列腺组织、15例良性前列腺增生组织 (BPH)、5 6例前列腺癌标本中Clusterin的表达水平。　结果　 3种组织中Clusterin的阳性及弱阳性表达率为 81% (67/83 ) ,其中前列腺正常、增生、癌组织中阳性及弱阳性表达率分别为17% (2 /12 )、73 % (11/15 )、96% (5 4/5 6)。前列腺癌组织中Clusterin表达水平明显高于前列腺正常 (t=8 82 ,P <0 0 1)及增生 (t =7 63 ,P <0 0 1)组织 ,且在癌组织中与肿瘤病理分级 (r =0 64 9,P <0 0 1)、临床分期 (r=0 60 9,P <0 0 1)呈正相关。　结论　Clusterin可能通过抗凋亡机制在前列腺癌的生物特性中发挥着重要的作用