The Prostate Cancer gene 3 assay: indications for use in clinical practice

Impact of Histopathological Prostate Inflammation on Urine-Based Prostate Cancer Prediction Using the Prostate Cancer Gene 3 Score

INTRODUCTION

The Prostate Cancer gene 3 (PCA3) urine test has gained importance in the diagnostic workup of prostate cancer (PC). Limited evidence suggests that PCA3 is not altered in the presence of inflammation.

OBJECTIVE

To assess the impact of histological inflammation on PCA3.

METHODS

PCA3 was evaluated in patients prior to prostate biopsy (n = 193) and to radical prostatectomy (n = 197). In patients without PC, inflammation was assessed and quantified by individual scores integrating grade and extent. Uni- and multivariate analyses were performed to assess the impact of inflammation grade on PCA3.

RESULTS

The PCA3 scores prior to prostatectomy were lower (median 45) than those before positive biopsy (57; p = 0.008). Of 101 negative biopsies, 78% showed inflammation. The median PCA3 scores in the groups with no inflammation and with maximum grade 1 (n = 22), 2 (n = 38), and 3 (n = 19) inflammation were 45, 38, 27, and 25 (p = 0.016). The multivariate models revealed a decrease in PCA3 proportional to the grade and extent of inflammation (p < 0.04 each).

CONCLUSIONS

The present data imply that the PCA3 score decreases in the presence of inflammation, which is relevant, for instance, to testing after a recently performed biopsy. In general, inflammation should be regarded as a factor putatively influencing PCA3 and other available and upcoming PC tests.

The Value and Evaluability of the PCA3 Urine Assay in Prostate Carcinoma is Independent of the Tumor Localization

INTRODUCTION

The prostate cancer gene 3 (PCA3) test is based on the analysis of tumor cell mRNA in urine. As an exprimated urinary marker, its retrieval is subject to certain physical aspects like palpation pressure and detachment force during the squeezing of cells. Other potential factor of influence may be the distance the cells have to cover until they reach the urethra. Thus, it was investigated whether the localization of the tumors within the prostate with regard to the urethra and the seminal colliculus influences the PCA3 score.

METHODS

Prostatectomy specimens of 55 organ-confined prostate cancer patients were processed according to the Stanford protocol. For each prostatectomy specimen, a three-dimensional reconstruction including the surface of the prostate, the tumor areas and the urethra was created. By model simulating, virtual concentric tubes were placed around the urethra and spherical volumes were virtually positioned around the seminal colliculus at diameters of 8, 16 and 32 mm. Depending on localization, tumor volumes may or may not protrude into the tubes or spherical volumes. For each respective diameter, PCA3 levels were compared between the subgroup with and without protrusion of tumor tissue into the tube or spherical ball.

RESULTS

For none of the diameters, whether in tubes or spherical balls, were patients without intersection volumes-hence showing peripherally located tumors-found to have lower PCA3 levels. No clinical or histopathological parameter correlated with the PCA3 score.

CONCLUSION

The location of the tumor mass in the prostate with respect to the urethra or the seminal colliculus did not to affect the PCA3 score. Hence, the location of the tumor does not limit the validity of the PCA3 score, and even for exclusively peripherall y located tumors, this possible influencing factor did not lead to an artificial modulation of the PCA3 score.

Comparison Analysis of Dysregulated LncRNA Profile in Mouse Plasma and Liver after Hepatic Ischemia/Reperfusion Injury

Long noncoding RNAs (LncRNAs) have been believed to be the major transcripts in various tissues and organs, and may play important roles in regulation of many biological processes. The current study determined the LncRNA profile in mouse plasma after liver ischemia/reperfusion injury (IRI) using microarray technology. Microarray assays revealed that 64 LncRNAs were upregulated, and 244 LncRNAs were downregulated in the plasma of liver IRI mouse. Among these dysregulated plasma LncRNAs, 59-61% were intergenic, 22-25% were antisense overlap, 8-12% were sense overlap and 6-7% were bidirectional. Ten dysregulated plasma LncRNAs were validated by quantitative PCR assays, confirming the accuracy of microarray analysis result. Comparison analysis between dysregulated plasma and liver LncRNA profile after liver IRI revealed that among the 308 dysregulated plasma LncRNAs, 245 LncRNAs were present in the liver, but remained unchanged. In contrast, among the 98 dysregulated liver LncRNAs after IRI, only 19 were present in the plasma, but remained unchanged. LncRNA AK139328 had been previously reported to be upregulated in the liver after IRI, and silencing of hepatic AK139328 ameliorated liver IRI. Both microarray and RT-PCR analyses failed to detect the presence of AK139328 in mouse plasma. In summary, the current study compared the difference between dysregulated LncRNA profile in mouse plasma and liver after liver IRI, and suggested that a group of dysregulated plasma LncRNAs have the potential of becoming novel biomarkers for evaluation of ischemic liver injury.

Dysregulation of cell cycle related genes and microRNAs distinguish the low- from high-risk of prostate cancer

Background

Prostate cancer (PCa) is a biologically heterogeneous disease with considerable variation in clinical aggressiveness. In this study, bioinformatics was used to detect the patterns of gene expression alterations of PCa patients.

Methods

The gene expression profile GSE21034 and GSE21036 were downloaded from Gene Expression Omnibus (GEO) database. Significantly changed mRNA transcripts and microRNAs were identified between subtypes with favorable (cluster 2) and unfavorable (cluster 5) prognosis by two-side unequal variances t test. MicroRNAs and their potential target genes were identified by TargetScan and miRTarBase, respectively. Besides, the overlapped genes between the target genes of microRNAs and mRNA transcripts were assessed by Fisher’ exact test (one side). The functional annotation was performed by DAVID, followed by construction of protein-protein interaction (PPI) network.

Results

Compared to cluster 2, 1556 up-regulated and 1288 down-regulated transcripts were identified in cluster 5. Total 28 microRNAs were up-regulated and 30 microRNAs were down-regulated in cluster 5. Besides, 12 microRNAs target transcripts were significantly overlapped with down-regulated transcripts in cluster 5 with none of them was found overlapped with up-regulated transcripts. Functional annotation showed that cell cycle was the most significant function. In the PPI network, BRCA1, CDK1, TK1 and TRAF2 were hub protein of signature genes in cluster 5, and TGFBR1, SMAD2 and SMAD4 were hub proteins of signature gnens in cluster 2.

Conclusions

Our findings raise the possibility that genes related with cell cycle and dysregulated miRNA at diagnosis might have clinical utility in distinguishing low- from high-risk PCa patients.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_156

False-positive prostate cancer markers in a man with symptomatic urethral Chlamydia trachomatis infection

Summary

Symptomatic male urethral Chlamydia trachomatis infection resulted in inflammation of the prostate, with associated increases in both prostate-specific (PSA) and prostate cancer-specific (PCA3) markers with prostate biopsies showing no evidence of malignancy.

Potential of the gastric motility drug lorglumide in prostate cancer imaging

The use of tissue-specific receptor ligands is a promising approach for cancer diagnostics and therapy. Lorglumide, a highly effective competitive ligand for the cholecystokinine-A receptor (CCKRA) was conjugated to a fluorescent dye and a magnetic resonance imaging (MRI) contrast agent to obtain a bifunctional marker for tissue with high CCKRA expression. An intermediate conjugate containing only lorglumide and a fluorescent dye was also produced. By performing CCKRA mRNA expression analysis on carcinoma cell lines we found that CCKRA is highly expressed in PC3 prostate carcinoma cells compared to U373 glioma and U2OS osteosarcoma cells. Uptake, specificity and detection sensitivity of both lorglumide conjugates was evaluated by confocal laser scanning microscopy, fluorescence activated cell sorting (FACS) and magnetic resonance relaxometry. While the conjugate containing only lorglumide and rhodamine isothiocyanate as fluorescent dye showed clearly higher uptake than the bifunctional conjugate in FACS analysis, both conjugates clearly showed preferential staining of the PC3 prostate carcinoma cells. Magnetic resonance relaxometry experiments with the bifunctional conjugate containing the MRI contrast agent gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid confirmed the higher PC3-affinity of the lorglumide ligand. Confocal laser scanning microscopy images of PC3/U2OS mixed cell cultures incubated with the bifunctional conjugate also clearly showed PC3 preference and cytoplasmic dot-like staining concurring with uptake by receptor binding and subsequent receptor internalization. Considering these results, CCKRA ligands like lorglumide could play a role in the future design of prostate-cancer-specific markers.

Contemporary role of prostate cancer gene 3 in the management of prostate cancer

PURPOSE OF REVIEW

With increasing evidence that prostate-specific antigen (PSA)-based screening can reduce disease-specific mortality but coincides with unacceptable levels of unnecessary testing and the diagnosis of potentially nonlife-threatening disease, the need for new, more specific biomarkers is urgent. Within this context the role of the prostate cancer gene 3 (PCA3) test is evaluated.

RECENT FINDINGS

Studies investigating the value of PCA3 as a diagnostic test virtually all show a beneficial effect as compared to PSA with respect to specificity. Beside the fact that most of these studies are subject to potential bias, the observed increased specificity was accompanied by relatively low sensitivities. Two studies, attempting to avoid selection bias as much as possible, show a marginal beneficial effect of the PCA3 test. Data on PCA3 as a staging tool for prostate cancer remain inconclusive.

SUMMARY

The PCA3 test is not capable of replacing the PSA test in clinical practice and an appropriate cut-off level with acceptable performance characteristics is hard to define. Its value as a first-line diagnostic test is limited. The addition of PCA3 to risk assessment tools leads to an increase in predictive capability. Data relating to the accuracy of PCA3 on prostate cancer staging are contradictory and PCA3 as prognostic test should be subject of future studies.

EFEMP1 as a novel DNA methylation marker for prostate cancer: array-based DNA methylation and expression profiling

PURPOSE

Abnormal DNA methylation is associated with many human cancers. The aim of the present study was to identify novel methylation markers in prostate cancer (PCa) by microarray analysis and to test whether these markers could discriminate normal and PCa cells.

EXPERIMENTAL DESIGN

Microarray-based DNA methylation and gene expression profiling was carried out using a panel of PCa cell lines and a control normal prostate cell line. The methylation status of candidate genes in prostate cell lines was confirmed by real-time reverse transcriptase-PCR, bisulfite sequencing analysis, and treatment with a demethylation agent. DNA methylation and gene expression analysis in 203 human prostate specimens, including 106 PCa and 97 benign prostate hyperplasia (BPH), were carried out. Further validation using microarray gene expression data from the Gene Expression Omnibus (GEO) was carried out.

RESULTS

Epidermal growth factor-containing fibulin-like extracellular matrix protein 1 (EFEMP1) was identified as a lead candidate methylation marker for PCa. The gene expression level of EFEMP1 was significantly higher in tissue samples from patients with BPH than in those with PCa (P < 0.001). The sensitivity and specificity of EFEMP1 methylation status in discriminating between PCa and BPH reached 95.3% (101 of 106) and 86.6% (84 of 97), respectively. From the GEO data set, we confirmed that the expression level of EFEMP1 was significantly different between PCa and BPH.

CONCLUSION

Genome-wide characterization of DNA methylation profiles enabled the identification of EFEMP1 aberrant methylation patterns in PCa. EFEMP1 might be a useful indicator for the detection of PCa.

Performance of the prostate cancer antigen 3 (PCA3) gene and prostate-specific antigen in prescreened men: exploring the value of PCA3 for a first-line diagnostic test

BACKGROUND

The performance characteristics of serum prostate-specific antigen (PSA) as a diagnostic test for prostate cancer (PCa) are poor. The performance of the PCa antigen 3 (PCA3) gene as a primary diagnostic is unknown.

OBJECTIVE

Assess the value of PCA3 as a first-line diagnostic test.

DESIGN, SETTING AND PARTICIPANTS

Participants included men aged 63-75 who were invited for rescreening in the period from September 2007 to February 2009 within the European Randomised Study of Screening for Prostate Cancer, Rotterdam section.

INTERVENTIONS

Lateral sextant biopsies were performed if the serum PSA value was > or =3.0 ng/ml and/or the PCA3 score was > or =10.

MEASUREMENTS

Measurements included distribution and correlation of PSA value and PCA3 score and their relation to the number of cases and the characteristics of PCa detected. Additional value of PCA3 was included in men with previous negative biopsy and/or PSA <3.0 ng/ml.

RESULTS AND LIMITATIONS

In 721 men, all biopsied, 122 PCa cases (16.9%) were detected. Correlation between PSA and PCA3 is poor (Spearman rank correlation: ρ=0.14; p<0.0001). A PSA > or =3.0 ng/ml misses 64.7% of the total PCa that can be detected with the sextant biopsy technique and 57.9% of serious PCa (T2a or higher and/or Gleason grade > or =4, n=19), and 68.2% of biopsies could have been avoided; the respective data for PCA3 > or =35 are 32%, 26.3%, and 51.7%. Performance of PCA3 in men with low PSA (area under the curve [AUC]: 0.63) and/or previous negative biopsy (AUC: 0.68) is unclear but has limited reliability due to small numbers.

CONCLUSIONS

PCA3 as a first-line screening test shows improvement of the performance characteristics and identification of serious disease compared with PSA in this prescreened population.