Prostate Stem Cell Antigen mRNA Research Articles

The PSCA rs2294008 (C/T) Polymorphism Increases the Risk of Gastric and Bladder Cancer: A Meta-Analysis.

Background: It has been reported that prostate stem cell antigen (PSCA) is overexpressed in certain cancer types and confers poor prognoses. The rs2294008 (C/T) polymorphism of PSCA is considered to be associated with risk for gastric, bladder, and colorectal cancers; however, these studies have produced inconsistent results, so we performed this meta-analysis to verify the association between the PSCA rs2294008 (C/T) polymorphism and cancer risk. Methods: A systematic literature search was performed using PubMed, EMBASE, and the Chinese National Knowledge Infrastructure, through October 20, 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association between the PSCA rs2294008 (C/T) polymorphism and cancer risk. In addition, we explored PSCA mRNA expression in cancers through online databases. Results: In total, 45 articles met our inclusion criteria and were analyzed, including 37,586 cancer cases and 51,197 non-cancer controls. Except in the recessive model, the pooled effect indicated the PSCA rs2294008 T allele was associated with an increased overall cancer risk (T vs. C: OR = 1.120, 95% CI = 1.056-1.188, p < 0.01; TT vs. CC: OR = 1.206, 95% CI = 1.066-1.364, p = 0.03; CT vs. CC: OR = 1.249, 95% CI = 1.151-1.356, p < 0.01; [CT+TT] vs. CC: OR = 1.248, 95% CI = 1.147-1.359, p < 0.01; TT vs. [CT+CC]: OR = 1.051, 95% CI = 0.954-1.156, p = 0.314). In the subgroup analysis, there were significant associations between the rs2294008 T allele and increased risk of bladder and gastric cancer. Two different online tools were used to explore the PSCA mRNA levels in cancer and the corresponding normal adjacent tissues. We found that expression of PSCA was significantly lower in gastric cancer patients. Conclusions: The PSCA rs2294008 T polymorphism is related to increased cancer susceptibility, especially for gastric and bladder cancers. This polymorphism results in a decreased PSCA expression level in gastric cancer.

Prostate stem cell antigen mRNA in blood is a predictor of survival after radical prostatectomy in patients with high-risk prostate cancer.

ObjectivesTo investigate whether the preoperative detection of prostate stem cell antigen (PSCA) mRNA in blood has predictive value for biochemical recurrence, overall survival, and cancer-specific survival after radical prostatectomy in patients with high-risk prostate cancer.ResultsMedian age was 67 years (interquartile range: 63-71), and median follow-up was 41 months (interquartile range: 25–65). PSCA mRNA was detected in 151 patients (51.1%). Biochemical recurrence was developed in 101 patients (34.2%), and all-cause mortality and prostate cancer-specific mortality occurred in 17 (5.7%) and 8 (2.7%) patients, respectively. Kaplan–Meier analysis revealed significant differences in biochemical recurrence, overall survival, and cancer-specific survival according to PSCA mRNA positivity. Cox regression hazards model analysis showed that PSCA mRNA positivity was an independent predictor of biochemical recurrence, overall survival, and cancer-specific survival.ConclusionsPSCA mRNA in the peripheral blood was related to poor prognosis. Detection of PSCA mRNA by polymerase chain reaction in peripheral blood can be used to predict survival after radical prostatectomy in patients with high-risk prostate cancer. Future study with larger cohort and long-term follow-up is required to confirm this finding.Materials and methodsA total of 295 patients with high-risk prostate cancer scheduled to undergo radical prostatectomy were prospectively enrolled from 2008 to 2016. Nested reverse transcription polymerase chain reaction was used to detect cells with PSCA mRNA in peripheral blood. The predicting ability of PSCA mRNA positivity for biochemical recurrence, overall survival, and cancer-specific survival after radical prostatectomy was evaluated.

Decrease in PSCA expression caused by Helicobacter pylori infection may promote progression to severe gastritis.

SNP rs2294008 in Prostate Stem Cell Antigen (PSCA) and decreased PSCA expression are associated with gastric cancer. The objective of this study is to investigate the role of rs2294008 and PSCA expression in the gastritis-gastric cancer carcinogenic pathway. We conducted a case-control association study of H. pylori-infected gastritis and gastric cancer. rs2294008 was associated with the progression to chronic active gastritis (P = 9.4 × 10–5; odds ratio = 3.88, TT + TC vs CC genotype), but not with H. pylori infection per se nor with the progression from active gastritis to gastric cancer. We also assessed the association of rs2294008 with PSCA mRNA expression in the gastric mucosa at various disease stages and found that rs2294008 was associated with PSCA expression (P = 1.3 × 10–12). H. pylori infection (P = 5.1 × 10–8) and eradication therapy (P < 1 × 10–11) resulted in the reduced and increased PSCA expression, respectively, indicating negative regulation of PSCA expression by H. pylori infection. PSCA expression was decreased in severe gastritis compared with mild gastritis only among T allele carriers. Our findings revealed the regulation of PSCA expression by host genetic variation and bacterial infection might contribute to gastritis progression after H. pylori infection.

Prostate stem cell antigen (PSCA) mRNA expression in peripheral blood in patients with benign prostatic hyperplasia and/or prostate cancer.

The aim of this study was to determine whether detection of prostate stem cell antigen (PSCA) expression in BPH might be associated with the subsequent presence of Prostate cancer (PCa) and also to determine whether detection of PSCA expression has potential for prognosis in PCa. This study was comprised of 112 PCa patients, 111 BPH patients and 120 control subjects. We employed reverse-transcriptase polymerase chain reaction (RT-PCR) to detect PSCA mRNA-bearing cells in peripheral blood. PSCA mRNA was detected in the peripheral blood of 71.4% PCa patients and in 13.5% of patients with BPH by RT-PCR. PSCA was positive in 80% of high-grade diseases compared with 20% of low-grade diseases (P = 0.01). Whereas only 38.8% of prostate-confined diseases were PSCA positive, 61.2% of extraprostatic diseases were PSCA positive (P < 0.001). Patients with a lymphovascular invasion of tumor emboli tended to be PSCA positive (P = 0.02). BPH patients with RT-PCR PSCA positive were significantly more likely to develop prostate cancer (OR = 16, 95% CI = 8.1-31.6, P < 0.001). In conclusion, RT-PCR PSCA positivity is significantly associated with the Gleason score, LV tumor emboli and whether or not the tumor was organ confined. In this study, RT-PCR PSCA detection may be a promising tumor marker of diagnostic and metastasis detection for patients with prostate cancer. Also, it may be an important test for predicting BPH patients who are at high risk of subsequent cancer development.

The Quantified Level of Circulating Prostate Stem Cell Antigen mRNA relative to GAPDH Level Is a Clinically Significant Indictor for Predicting Biochemical Recurrence in Prostate Cancer Patients after Radical Prostatectomy.

The study quantified the relative absolute PSCA level in relation to the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) level in the peripheral blood of 478 hormone-naive prostate cancer (PC) patients who underwent radical prostatectomy from 2005 to 2012 and evaluated its prognostic significance as a risk factor for predicting biochemical recurrence (BCR), compared to known parameters. Nested real-time polymerase chain reaction (RT-PCR) and gel electrophoresis detected PSCA levels and measured the PSCA/GAPDH ratio. Clinicopathological data from the institutional database were examined to determine the adequate cut-off level to predict postoperative BCR. A total of 110 patients had a positive PSCA result (23.0%) via RT-PCR (mean blood ratio 1.1 ± 0.4). The BCR was significantly higher in the PSCA-positive detection group (p = 0.009). A multivariate model was created to show that a PSCA/GAPDH ratio between 1.0 and 1.5 (HR 12.722), clinical T2c stage (HR 0.104), preoperative PSA (HR 1.225), extraprostatic capsule extension (HR 0.006), lymph node dissection (HR 16.437), and positive resection margin (HR 27.453) were significant predictive factors for BCR (p < 0.05). The study showed successful quantification of PSCA with its significance for BCR-related risk factor; however, further studies are needed to confirm its clinical predictive value.

Association between PSCA mRNA expression levels and rs2294008 polymorphism in transitional cell cancer of the bladder.

Prostate stem cell antigen (PSCA) was originally identified as a gene that is overexpressed in prostate cancer, and correlates with prostate cancer progression and prognosis. Recently, a significant association has been identified between the PSCA rs2294008 (C>T) polymorphism and the risk of developing bladder cancer. Therefore, the present study investigated the different expression levels of PSCA mRNA in transitional cell carcinoma (TCC) of the bladder and normal bladder tissue. Furthermore, the association between PSCA mRNA expression levels in TCC and different rs2294008 (C>T) genotypes and various clinicopathological features, including tumor stage and grade, were evaluated. Reverse transcription-quantitative polymerase chain reaction was performed on 80 TCC samples and 38 samples of normal bladder urothelium from TCC patients who underwent transurethral resection of bladder tumor or radical cystectomy at the Beijing Friendship Hospital (Beijing, China) between September 2010 and May 2011. Genomic DNA was extracted from tumor tissue and sequenced to determine the rs2294008 (C>T) genotype. PSCA mRNA expression was detected in all samples (100%); however, tumor samples exhibited significantly higher PSCA expression levels compared with the normal urothelium samples (P=0.038). PSCA mRNA expression was positively correlated with the histological grade of the tumor (G1-2 vs. G3; P=0.001); however, no significant difference was detected between patients with superficial (Ta or T1) and muscle-invasive (≥pT2) tumors (P=0.250). Thus, PSCA mRNA expression levels were associated with TCC and tumor histological grade, but not the tumor stage. Additionally, PSCA mRNA expression levels were significantly higher in T allele carriers compared with CC homozygous patients (P=0.001), indicating that the presence of the T allele may increase PSCA mRNA expression. Therefore, rs2294008 (C>T) may be associated with the biological properties of TCC and, thus, future research should focus on the physiological function of PSCA and the mechanism of rs2294008.

Abstract 5126: Allele-specific effect of rs2294008 on mRNA and protein expression of the prostate stem cell antigen (PSCA) in human normal and tumor bladder tissue

Abstract Background: A recent GWAS identified a SNP rs2294008 within the prostate stem cell antigen (PSCA) at 8q24.3 as a risk factor for bladder cancer, [OR=1.13 (1.09-1.17), p=4E-11, Rothman, 2010]. PSCA encodes a GPI-anchored cell membrane glycoprotein expressed in the prostate, bladder, stomach and pancreas. A transcript with the non-risk C allele of rs2294008 generates a protein of 114 amino acids, while the risk T allele creates a novel upstream translation start site (acg-&amp;gt;aTg) that extends the N-terminal leader peptide by 9 amino acids, to generate a protein of 123 amino acids. A humanized monoclonal anti-PSCA antibody is already used in clinical trials for prostate and pancreatic cancer, but the functional roles of PSCA and its genetic variants remain unknown. Methods: We performed RNA-sequencing in 3 matched normal-tumor bladder tissue samples and mRNA expression analysis in 42 tumor and 41 normal bladder tissue samples (24 matched normal-tumor pairs). Genotyping and AEI (Allelic Expression Imbalance) was performed using an allelic discrimination genotyping assay. PSCA isoforms with T and C alleles were cloned into a pFC14A CMV Flexi expression vector. Protein PSCA expression in normal/tumor bladder tissues and transfected cells was analyzed with Western blot and immunohistochemistry (IHC). Results and Conclusion: RNA-sequencing detected PSCA expression in all bladder tissue samples. Analysis of three samples heterozygous for rs2294008 showed evidence of strong AEI - 90% of all PSCA transcripts carried the risk T allele, while only 10% showed the non-risk C allele. Similar pattern of expression was observed for 11 other transcribed SNPs within the PSCA, but not for SNPs located in neighboring genes, Ly6K and JRK, implying that the AEI is specific for PSCA. By using an allele-specific expression assay that measured allelic ratio of rs2294008 in PSCA transcripts, we also confirmed AEI detected by RNA-seq. PSCA mRNA expression was strongly increased in individuals with risk T allele in both normal (ptrend =0.0155 for rs2294008) and tumor samples rs2294008 (ptrend=0.0054), which is further indicative of effect of AEI. IHC on a panel of paired normal-tumor bladder tissue microarrays (TMA) confirmed mRNA expression results and showed PSCA protein expression only in carriers of risk genotype (TT) but not in non-risk genotype (CC), both in tumor and normal bladder tissue sections. Analysis of recombinant PSCA expression in transfected cells showed stronger surface expression of the risk T allele, compared to C allele. In conclusion, we show preferential mRNA and protein expression of PSCA in individuals with risk allele T of rs2294008. Thus, genotyping information for PSCA rs2294008 may emerge as an important decisive factor for response to PSCA antibody mediated treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5126. doi:1538-7445.AM2012-5126

Peripheral blood reverse transcription PCR assay for prostate stem cell antigen correlates with androgen‐independent progression in advanced prostate cancer

Recent studies show that prostate stem cell antigen (PSCA) mRNA positivity in peripheral blood correlates with disease progression in prostate cancer (PCa). Our study is to evaluate the association between peripheral blood PSCA status and androgen-independent progression (AIP) in a cohort of patients with advanced PCa under androgen deprivation therapy (ADT). PSCA mRNA was measured by reverse transcriptase polymerase chain reaction (RT-PCR) assay in peripheral blood samples from 116 patients with locally advanced or metastatic PCa who were treated with primary ADT and from 40 healthy controls. The Kaplan-Meier and the Cox proportional hazards methods were used to assess potential predictors of AIP. Pretreatment RT-PCR-PSCA was positive in 37 (31.9%) of 116 patients. All healthy volunteers were negative for PSCA mRNA. Although seven (14.9%) of 47 patients with Gleason score ≤7 were PSCA positive, 30 (43.5%) of 69 patients with Gleason score >7 were PSCA positive (p = 0.016). PSCA mRNA was detected in 28 (58.3%) of 48 patients with metastatic PCa, compared to nine (13.2%) of 68 patients with locally advanced disease (p = 0.012). AIP developed in 59 (50.9%) patients during a median follow-up period of 35.4 months (range: 4-78 months). Patients with PSCA negativity experienced significantly longer remissions compared to those with PSCA positivity (log-rank test: p < 0.001). Multivariate Cox regression analysis further demonstrated that PSCA positivity had a significantly increased risk of AIP (HR = 4.303, 95% CI: 3.761-7.482, p < 0.001). Pretreatment RT-PCR PSCA positivity in peripheral blood independently signals the presence of AIP in patients with advanced PCa treated with ADT.

Prostate cancer targeting motifs: Expression of ανβ3, neurotensin receptor 1, prostate specific membrane antigen, and prostate stem cell antigen in human prostate cancer cell lines and xenografts

Membrane receptors are frequent targets of cancer therapeutic and imaging agents. However, promising in vitro results often do not translate to in vivo clinical applications. To better understand this obstacle, we measured the expression differences in receptor signatures among several human prostate cancer cell lines and xenografts as a function of tumorigenicity. Messenger RNA and protein expression levels for integrin α(ν) β(3), neurotensin receptor 1 (NTSR1), prostate specific membrane antigen (PSMA), and prostate stem cell antigen (PSCA) were measured in LNCaP, C4-2, and PC-3 human prostate cancer cell lines and in murine xenografts using quantitative reverse transcriptase polymerase chain reaction, flow cytometry, and immunohistochemistry. Stable expression patterns were observed for integrin α(ν) and PSMA in all cells and corresponding xenografts. Integrin β(3) mRNA expression was greatly reduced in C4-2 xenografts and greatly elevated in PC-3 xenografts compared with the corresponding cultured cells. NTSR1 mRNA expression was greatly elevated in LNCaP and PC-3 xenografts. PSCA mRNA expression was elevated in C4-2 xenografts when compared with C4-2 cells cultured in vitro. Furthermore, at the protein level, PSCA was re-expressed in all xenografts compared with cells in culture. The regulation of mRNA and protein expression of the cell-surface target proteins α(ν) β(3), NTSR1, PSMA, and PSCA, in prostate cancer cells with different tumorigenic potential, was influenced by factors of the microenvironment, differing between cell cultures and murine xenotransplants. Integrin α(ν) β(3), NTRS1 and PSCA mRNA expression increased with tumorigenic potential, but mRNA expression levels for these proteins do not translate directly to equivalent expression levels of membrane bound protein.

PSCA mRNA expression in preoperatively negative prostate biopsies predicts incidental prostate cancer in patients undergoing transurethral resection of the prostate for benign prostatic hyperplasia

Recent data showed that prostate stem cell antigen (PSCA) mRNA expression is predictive of the subsequent cancer in BPH patients treated with TURP. This study was to determine whether PSCA mRNA expression in preoperatively negative biopsies identified the presence of incidental prostate cancer (IPCa) on TURP tissues analysis. PSCA in situ hybridization was performed in preoperatively negative prostatic biopsies taken from 592 enrolled BPH patients. Predictive performance of PSCA mRNA for IPCa was evaluated by the Cox proportional hazards models. PSCA mRNA positivity in negative biopsy specimens was detected in 84 (14.2%) of 592 men. Of those 84 patients, 57 were histopathologically identified as having PCa on their TURP tissues. None of the rest 508 men with negative PSCA mRNA expression were diagnosed with IPCa. Spearman's rank correlation coefficient showed that PSCA mRNA expression levels were correlated significantly and positively with Gleason score (r = 0.80, P < 0.001) and clinical stage (r = 0.86, P < 0.001). A multivariate Cox model demonstrated that only PSCA mRNA positivity was predictive of the IPCa presence on TURP (HR = 4.04; 95% CI: 2.12-5.42; P < 0.001), with the concordance index of 0.878. PSCA mRNA positivity in negative biopsies is a promising marker for the presence of IPCa in BPH patients.

PSCA expression in invasive micropapillary carcinoma of breast

To study the expression of prostate stem cell antigen (PSCA) at protein and mRNA levels in invasive micropapillary carcinoma of the breast (IMPC) and to analyze the relationship between PSCA expression and clinicopathologic features. The expression of PSCA protein was analyzed by immunohistochemistry (LSAB) in 66 cases of IMPC and 67 cases of invasive ductal carcinoma, not otherwise specified (IDC-NOS). The association between PSCA expression and clinicopathologic features was also analyzed in IMPC. Furthermore, RT-PCR was used to detect PSCA mRNA in 10 cases of primary IMPC and 10 cases of primary IDC-NOS with paired normal breast tissues, each from the same subject. Immunohistochemical analysis revealed the overexpression of PSCA in 47 of 66 (71.2%) cases of IMPC and 35 of 67 (52.2%) IDC-NOS. Statistical analysis showed a significant difference of PSCA expression between IMPC and IDC-NOS (P = 0.024). In IMPC, the expression of PSCA was correlated with lymph nodes metastasis (P = 0.039). RT-PCR showed the mRNA level of PSCA was significantly higher in primary IMPC and IDC-NOS tissue than that in paired normal breast tissue (7/10 and 5/10, respectively), and it was also significantly higher in primary IMPC tissue than that in IDC-NOS tissue. PSCA might play an important role in lymph node metastasis in IMPC.

Genetic variation in PSCA and bladder cancer susceptibility in a Chinese population

Recently, two genome-wide association studies identified a significant association between the prostate stem cell antigen (PSCA) rs2294008 (C>T) polymorphism and risk of diffuse-type of gastric cancer in Asians and bladder cancer in Caucasians, respectively. PSCA has been reported highly expressed in bladder cancer and been considered as a useful marker for diagnosis and progression of bladder cancer. To determine whether rs2294008 polymorphism is associated with risk of bladder cancer in Chinese populations, we conducted a hospital-based case-control study of 581 cases and 580 controls. Sixteen normal bladder tissues adjacent to tumors were used to evaluate the functionality of this polymorphism. We genotyped the rs2294008 polymorphism and assessed its association with risk of bladder cancer and messenger RNA (mRNA) expression in normal bladder tissues. A significant increased risk of bladder cancer was found for rs2294008 CT/TT genotypes (adjusted odds ratio, 1.38; 95% confidence interval, 1.09-1.75) compared with the CC genotype. Furthermore, analysis of PSCA mRNA expression identified a clear correlation of rs2294008 with expression levels of PSCA mRNA. These results indicated that the rs2294008 polymorphism of PSCA gene may play a role in bladder cancer carcinogenesis and it could be served as a biomarker for genetic susceptibility to bladder cancer in Chinese populations.

Prostate stem cell antigen mRNA in peripheral blood as a potential predictor of biochemical recurrence in high‐risk prostate cancer

To determine whether the presence of prostate stem cell antigen (PSCA) mRNA in peripheral blood can predict biochemical recurrence (BCR) after radical prostatectomy in patients with high-risk prostate cancer. High-risk disease was defined based on the presence of any one of the following three risk factors: prostate-specific antigen (PSA) > or = 20 ng/ml, a biopsy Gleason score (GS) > or = 8, or clinical stage > or = T2c. Nested reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to detect PSCA mRNA-bearing cells in peripheral blood. The relationship between PSCA detection and BCR after surgery was evaluated. Of the 250 patients, 103 (36.8%) with high-risk disease were included in the analysis. PSCA-mRNA was detected in 17 (16.5%) of these patients. Patients with high GS (> or = 7) tended to be PSCA-mRNA positive status (P = 0.045). Over a median 23 months of follow-up (range 3-47 months), BCR developed in 27 patients (26.2%). Cox regression hazards model analysis revealed that a RT-PCR PSCA positivity (HR, 4.549; 95%CI, 1.685-12.279; P = 0.003) independently increased the risk of BCR. The presence of PSCA mRNA in peripheral blood is a significant predictor of BCR after radical prostatectomy in high-risk prostate cancer.

Prostate stem cell antigen mRNA expression in preoperatively negative biopsy specimens predicts subsequent cancer after transurethral resection of the prostate for benign prostatic hyperplasia

Recent data showed that prostate stem cell antigen (PSCA) mRNA expression in transurethral resection of the prostate (TURP)-resected tissues predicted the subsequent prostate cancer after TURP in benign prostatic hyperplasia (BPH) patients with both PSA < 4.0 ng/ml and normal DRE findings. This study was to determine whether PSCA mRNA positivity in preoperatively negative prostatic biopsy samples from BPH men with PSA > 4.0 ng/ml and/or suspicious DRE findings had predictive performance following TURP. PSCA in situ hybridization was performed on negative prostatic biopsies taken before TURP from 166 enrolled symptomatic BPH patients, who were continuously followed for 5 years postoperatively. Predictive performance of PSCA mRNA for subsequent cancer onset was evaluated by univariate and multivariate Cox proportional hazards models with bootstrapping and concordance indices. PSCA mRNA was detected in 42/166 (25.3%) of the preoperatively negative biopsy specimens, with a mean positive-labeling cells of 31.6%, in which 31 patients were identified as having subsequent PCa on follow-up. Of 124 patients with negative expression for PSCA mRNA none were subsequently diagnosed with PCa. The examination of Spearman's rank correlation coefficient showed that PSCA mRNA expression levels were positively and statistically correlated with higher Gleason score (r = 0.88, P < 0.001) and clinical T stage (r = 0.84, P < 0.001). A final multivariate Cox proportional hazards model demonstrated that only PSCA mRNA expression in negative prostatic biopsies was predictive of the subsequent cancer development after TURP (hazard ratio = 3.49; 95% CI: 2.02-4.75; P < 0.001), with the concordance index of 0.893. This prospective study identifies PSCA mRNA in preoperatively negative prostatic biopsies as a significant predictor of subsequent cancer after TURP.

Circulating Prostate Tumor Cells Detected by Reverse Transcription-PCR in Men with Localized or Castration-Refractory Prostate Cancer: Concordance with CellSearch Assay and Association with Bone Metastases and with Survival

Reverse transcription-PCR (RT-PCR) assays have been used for analysis of circulating tumor cells (CTCs), but their clinical value has yet to be established. We assessed men with localized prostate cancer or castration-refractory prostate cancer (CRPC) for CTCs via real-time RT-PCR assays for KLK3 [kallikrein-related peptidase 3; i.e., prostate-specific antigen (PSA)] and KLK2 mRNAs. We also assessed the association of CTCs with disease characteristics and survival. KLK3, KLK2, and PSCA (prostate stem cell antigen) mRNAs were measured by standardized, quantitative real-time RT-PCR assays in blood samples from 180 localized-disease patients, 76 metastatic CRPC patients, and 19 healthy volunteers. CRPC samples were also tested for CTCs by an immunomagnetic separation system (CellSearch; Veridex) approved for clinical use. All healthy volunteers were negative for KLK mRNAs. Results of tests for KLK3 or KLK2 mRNAs were positive (> or =80 mRNAs/mL blood) in 37 patients (49%) with CRPC but in only 15 patients (8%) with localized cancer. RT-PCR and CellSearch CTC results were strongly concordant (80%-85%) and correlated (Kendall tau, 0.60-0.68). Among CRPC patients, KLK mRNAs and CellSearch CTCs were closely associated with clinical evidence of bone metastases and with survival but were only modestly correlated with serum PSA concentrations. PSCA mRNA was detected in only 7 CRPC patients (10%) and was associated with a positive KLK mRNA status. Real-time RT-PCR assays of KLK mRNAs are highly concordant with CellSearch CTC results in patients with CRPC. KLK2/3-expressing CTCs are common in men with CRPC and bone metastases but are rare in patients with metastases diagnosed only in soft tissues and patients with localized cancer.

The association of prostate stem cell antigen (PSCA) mRNA expression and subsequent prostate cancer risk in men with benign prostatic hyperplasia following transurethral resection of the prostate

Prior data showed prostate stem cell antigen (PSCA) mRNA expression in benign prostatic hyperplasia (BPH) tissues. The purpose of the present investigation was to determine whether PSCA mRNA expression in resected BPH samples was associated with the subsequent presence of cancer following transurethral resection of the prostate (TURP). PSCA in situ hybridization was performed on the TURP-resected tissues from 288 patients, who were histopathologically confirmed BPH without cancer. All these patients were continuously followed for 9-70 months postoperatively. Univariate and multivariate cox regression analyses were used to evaluate the predictive performance of PSCA mRNA for subsequent cancer onset following TURP. PSCA mRNA was detected in 93/288 (32.3%) of the resected BPH specimens, with a mean positive-labeling cells of 23.8%, in which 22 patients (23.7%) were identified as having PCa on follow-up. Of 195 patients with negative expression for PSCA mRNA 2 (1.0%) were subsequently found with PCa. PSCA mRNA expression levels were directly proportional to higher Gleason score and clinical T stage. Univariate and multivariate cox regression analyses demonstrated that only PSCA mRNA expression was predictive of the subsequent cancer development after TURP, however, PSA velocity was an univariately significant but not multivariately significant predictor. This prospective study identifies PSCA mRNA in BPH as a significant predictor of cancer development after TURP, suggesting that PSCA may be used to identify patients who are at high risk for subsequent cancer onset following TURP for BPH and the PSCA test may be useful when applied for repeat biopsies.

Flutamide reduced prostate cancer development and prostate stem cell antigen mRNA expression in high grade prostatic intraepithelial neoplasia

High-grade prostatic intraepithelial neoplasia (HGPIN) appears to represent an ideal target for chemoprevention of prostate cancer (PCa). HGPIN responds to androgen ablation and has prostate stem cell antigen (PSCA) mRNA expression. One hundred and seventy two patients with isolated HGPIN were randomized in a double-blind manner to receive flutamide 250 mg/day (86 cases) or a placebo (86 cases) for 12 months and were rebiopsied at 12 and 60 months. PSCA mRNA expression was assessed in the prestudy and 12-month biopsies by in situ hybridization. The incidence of subsequent PCa was 11.6% in the flutamide group when compared with 30.2% in the placebo group over a follow-up period of 5 years (p = 0.0027). PSCA mRNA expression levels were significantly declined after treatment compared with that before treatment (p < 0.001). After treatment, 66 patients had reduced PSCA mRNA expression, in whom none was found with cancer on follow-up, however, 13 cases had increased PSCA mRNA expression levels, in whom 11 were found with cancer. Cox regression analysis demonstrated that HGPIN with increased PSCA mRNA expression after flutamide had an increased relative risk of 4.33 to develop subsequent cancer (95% confidence intervals: 2.48-7.36; p < 0.001). Seventeen (19.8%) cases had the flutamide-associated side effects, which were graded as mild, but all did not discontinue study. Flutamide can effectively and safely reduce PCa development and significantly suppress PSCA mRNA expression in men with isolated HGPIN, whereas the increased PSCA mRNA expression after therapy may be a clinically adverse predictor for cancer onset.

Prostate stem cell antigen (PSCA) mRNA expression in prostatic intraepithelial neoplasia: implications for the development of prostate cancer

Prior data clearly demonstrated the expression of prostate stem cell antigen (PSCA) mRNA in prostatic intraepithelial neoplasia (PIN) tissues. The purpose of the present investigation was to determine whether PSCA mRNA expression was associated with the presence of cancer in this disease. One hundred seventeen men were diagnosed with isolated PIN on initial prostate biopsy, 51 with low-grade form (LGPIN), and 66 with high-grade form (HGPIN). PSCA mRNA expression in initial PIN and subsequent cancer was examined by in situ hybridization (ISH). The differences of the PSCA mRNA expression level between the groups were analyzed by the Chi-square and Student's t-test. Univariate and multivariate logistic regression analyses were performed to evaluate the predictive performance of PSCA mRNA. PSCA mRNA expression level in 34 subsequent cancers was statistically increased compared with their paired PIN (P < 0.001), with a Gleason's dependence. HGPIN showed statistically high PSCA mRNA expression compared with LGPIN (P < 0.01). PSCA mRNA expression levels were significantly stronger in the initial isolated LGPIN and isolated HGPIN with subsequent cancer than those without (P < 0.001 and P < 0.001, respectively). Multivariate logistic regression analysis demonstrated that only PSCA mRNA was predictive of the onset of subsequent cancer in patients with isolated LGPIN and in those with isolated HGPIN, respectively. Our data identify PSCA mRNA in initial PIN as a significant predictor of subsequent cancer, suggesting that PSCA implies in prostatic tumorigenesis and may be used to identify the patients with isolated PIN who are at high risk for cancer onset in the disease process.

External beam radiotherapy (EBRT) suppressed prostate stem cell antigen (PSCA) mRNA expression in clinically localized prostate cancer

Prostate stem cell antigen (PSCA), a recently identified glycosylphosphatidylinositol (GPI)-anchored cell surface protein belonging to the Thy-1/Ly-6 family of cell surface antigens, is overexpressed in human prostate cancer (PCa). Our recent data indicated that complete androgen ablation could significantly suppress PSCA mRNA expression in primarily organ-confined PCa. The effect of external beam radiotherapy (EBRT), one of the curative treatment options for localized PCa, on tumor PSCA mRNA expression has not been elucidated. The purpose of the present study was to investigate the variations in the expression levels of PSCA mRNA before and after EBRT, and further evaluate the prognostic value of PSCA in this disease. Between January 1999 and June 2005, 87 men with clinically localized adenocarcinoma of the prostate received only EBRT with a total dose of 65-70 Gy for 6.5-7 weeks. PSCA in situ hybridization (ISH) was performed on the cancerous pretreatment biopsy or transurethral resection of prostate (TURP) tissue and post-treatment biopsy tissue of all 87 men, respectively. Tumor cytoplasmic staining of PSCA mRNA was evaluated by two independent pathologists and the differences of PSCA mRNA expression levels between the samples before and after EBRT were analyzed using the Student's t-test. Twenty-four to seventy months continuous follow-up studies after treatment were performed and aimed at assessing the correlation of PSCA mRNA expression level with biochemical relapse and/or distant metastases from the cancer. The percent of cells positive for PSCA mRNA by ISH labeling declined from 71.2% (0-93%) +/- 9.7% before EBRT to 30.7% (0-90%) +/- 5.3% after EBRT (P<0.001). Before EBRT, 81 of 87 cases (93.1%) were positive for PSCA mRNA labeling, however, after EBRT the percentage of positive reactivity of PSCA mRNA was decreased to 62 of 81 cases (76.5%), in which 59 men (95.2%) were found without biochemical relapse or distant metastases on follow-up. This decline in PSCA mRNA labeling was directly proportional to higher pretreatment serum PSA level, higher tumor grade (Gleason score), and higher clinical T stage. The rest 19 cases had the increased percentage of cells positive for PSCA mRNA after EBRT, in which 15 cases developed biochemical relapse and/or distant metastases from tumor on follow-up. We found that EBRT for PCa can significantly suppress PSCA mRNA expression and the elevated PSCA mRNA level after EBRT may be a clinically adverse predictor for tumor progression.

The expression of prostate stem cell antigen in human clear cell renal cell carcinoma: a quantitative reverse transcriptase‐polymerase chain reaction analysis

To analyse the gene expression level of prostate stem cell antigen (PSCA) in human clear cell renal cell carcinoma (CC-RCC) and its relationship with conventional clinicopathological manifestations, to evaluate its prognostic value for patient outcome, and to determine the effect of PSCA on the progression of CC-RCC. We quantified PSCA mRNA level in human RCC cell lines (ACHN, A704, KPK-1, Caki-1, and Caki-2) and in 154 surgical tissue samples (81 from CC-RCC, 73 from normal kidney) using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The findings were analysed in relation to clinicopathological factors. Immunohistochemical expression was examined using confocal laser scanning light-microscopy. PSCA was overexpressed in all RCC cell lines. PSCA mRNA levels were significantly higher in CC-RCC than in normal kidney tissue samples (P < 0.001), in G2-G3 than in G1 tumours (P = 0.028), and in advanced disease (T3-T4) than in organ-confined (T1-T2) tumours (P = 0.016). There was significantly higher PSCA mRNA expression in patients with M1 than in those with M0 disease (P = 0.029). Patients in whom the lesions had high PSCA expression levels had a significantly worse prognosis than those with low PSCA expression levels (P = 0.044). Using immunohistochemical analysis there was markedly greater PSCA expression in CC-RCC than in normal kidney, and in advanced-disease high-grade tumours than in organ-confined low-grade tumours. A significant correlation was detected in the gene expression level of PSCA with histological grade, clinicopathological stage and prognosis in CC-RCC. Our data indicate that PSCA is associated with carcinogenesis and progression of CC-RCC.