Extracellular microRNAs recently provided valuable information including the site and the status of cancers. miR141 and miR375 are the most pronounced biomarkers for the diagnosis of high-risk prostate cancer. Here, we describe attomolar detection of miR141 and miR375 released from living prostate cancer cells through the use of a plasmonic nanowire interstice (PNI) sensor.

by Dr Taejoon Kang and Professor Bongsoo Kim

Background
Prostate-specific antigen
Prostate cancer (PC) represents 27% of all cancers in men and the second leading cause of cancer death for men worldwide [1]. In 2017 for the USA alone, there were approximately 161 360 cases of PC. PC has been diagnosed by digital rectal examination and the prostate-specific antigen (PSA) test. PSA is the only tissue-specific biomarker that can aid the early diagnosis of PC. The PSA blood test, however, has limited diagnostic accuracy for PC because PSA can be increased owing to other factors including benign prostatic hyperplasia or prostatitis as well as PC. The US Preventive Services Task Force even recommended that physicians should not routinely perform PC screening based on serum PSA levels [2]. Clearly, new biomarkers are needed to overcome this problem.

Recently, it has been reported that the level of free PSA (f-PSA) is decreased in men who have PC compared with those with benign conditions [3]. Therefore, various immunoassay technologies including enzyme-linked immunosorbent assay, fluorescence immunoassay, surface plasmon resonance (SPR), electrochemical immunosensor, dark-field microscopy, chemiluminescence, surface-enhanced Raman scattering (SERS), and dynamic light scattering have been employed for the quantitative analysis of f-PSA [3].

RNAs as prostate cancer biomarkers
Long noncoding RNAs (lncRNAs, ≥200 nucleotides) are often expressed in a disease-, tissue- or developmental-specific manner. Since lncRNAs are highly dysregulated in several cancer types and exhibit a high degree of tissue- and disease-specificity, lncRNAs are regarded as candidates for cancer diagnostic biomarkers [4]. Prostate Cancer Antigen 3 (PCA3) is a prostate-specific lncRNA that is overexpressed by 60- to 100-fold in >90% of prostate tumours compared to benign prostatic tissue. Urinary PCA3 has been used as a diagnostic biomarker for PC with a sensitivity of 58–82% and a specificity of 56–76%. The sensitivity and accuracy of PCA3 are increased when used in combination with α-methylacyl-CoA racemase. Urinary PCA3 is now widely used for PC diagnosis and has been approved by the US Food and Drug Administration (FDA). MicroRNAs (miRNAs) are single-stranded, small, and noncoding RNAs. The expression patterns of miRNAs in tissue and blood samples of patients are often closely associated with disease types and also disease stages, hinting that certain miRNAs can be compelling diagnostic markers [5]. In 2008, it was first reported that the level of miR141 is upregulated in the serum of metastatic PC compared with healthy controls and benign prostatic hyperplasia patients. Since then, miR141 and miR375 have been the most pronounced biomarkers for high-risk PC, including castrate-resistant PC and metastatic PC, which account for approximately 15% of PC diagnoses and have the potential to progress to a lethal phenotype [6].

Detection methods for nucleic acid biomarkers
For the detection of nucleic acid biomarkers, polymerase chain reaction (PCR) is the most extensively used analytical tool. Although PCR is considered the gold standard for the detection of gene biomarkers, it has drawbacks including a long amplification time and the risk of erroneously amplifying contaminants or unrelated gene sequences. To overcome these limitations, PCR-free assays have been developed by taking various sensing approaches such as fluorescence resonance energy transfer, colorimetry, SPR, electrochemistry, SERS, and so on. These methods have contributed to the advance of cancer diagnosis by reducing the drawbacks of PCR. SERS is a fascinating phenomenon that significantly increases the Raman signal of molecules located within nanoscale metallic interstices (hot spots). SERS has been employed for the sensitive detection of nucleic acid because of its single-molecule sensitivity, molecular specificity, and insensitivity to quenching. It is known that the SERS enhancement strongly depends on the detailed morphology of the metal nanostructure. Although a number of promising nanostructures that can be used as efficient SERS-active platforms have been proposed, it still remains a challenging task to develop a practical SERS sensor that can detect multiple nucleic acid biomarkers simultaneously while retaining high sensitivities. The use of single-crystalline noble metal nanowires (NWs) is highly advantageous for SERS-based detection because of their well-defined geometries, atomically smooth surfaces, and simple fabrication process [7]. Previously, we developed several noble metal NW-based SERS sensors including plasmonic nanowire interstice (PNI) sensor, particle-on-NW sensor, NW on a graphene sensor, and nanogap-rich Au NW sensor [8–15]. Among them, PNI nanostructures have been widely employed for the detection of several biochemical molecules. Particularly, by combining the PNI nanostructure with the bi-temperature hybridization process, we were able to detect miRNAs with near-perfect accuracy of single nucleotide polymorphism (SNPs) and at the extremely low detection limit of 100 aM. Here, we introduce a PNI sensor which can detect the extracellular miR141 and miR375 released from living PC cells into a culture medium. This sensor shows an extremely low detection limit of 100 aM for both miR141 and miR375, and a wide dynamic range from 100 aM to 100 pM, covering the typical concentration range of extracellular miRNAs in the bloodstreams of patients. Additionally, the PNI sensor can completely discriminate the single-base mismatches of miR141 and miR375. This excellent sensing capability of the PNI sensor enables the simultaneous detection of miR141 and miR375 released from the cells of PC cell lines (LNCaP and PC-3), showing the potential applicability to a novel PC diagnostic method.

Specific and sensitive detection of miRNA
To accurately determine the expression patterns of miRNAs in biological fluid samples, it is necessary to overcome the inconsistent measurement results caused by low specificities and complicated sensing procedures. For the ultra-specific and ultra-sensitive detection of miRNAs, we applied miRNA-specific bi-temperature hybridizations to Au NW surfaces, where short miRNAs can readily crawl into the narrow hot spots of the PNI sensor for effective SERS detection. The probe locked nucleic acid (LNA)-modified PNI sensors were incubated with miRNAs at 42 °C and subsequently incubated with Cy5-labeled reporter LNA at 64 °C (Fig. 1a). If the target miRNAs have perfectly complementary sequences to both probe and reporter LNAs, sandwiched complexes of probe LNA-miRNA-reporter LNA can be stably formed on a PNI sensor, providing strong SERS signals of Cy5. In contrast, when the sample only contains single-base mismatched miRNAs, little signal was observed. Figure 1(b) displays the intensity of the Cy5 1580 cm⁻¹ band plotted as a function of the miR141 (magenta) and miR375 (blue) concentrations. Both intensities were quite linearly increased throughout the concentration range from 100 aM to 100 pM in spite of the different sequences of miR141 and miR375. To investigate the specificity of a PNI sensor, we prepared four kinds of single-base mismatched miRNAs (miR141 A, miR141 B, miR375 A, and miR375 B). The miR141 A and miR375 A had a mismatched single base on the probe LNA recognition site, respectively, and the miR141 B and miR375 B had a mismatched single base on the reporter LNA recognition site. Figure 1(c,d) shows the plot of Cy5 1580 cm⁻¹ band intensity obtained from the PNI sensors for perfectly matched and single-base mismatched miRNAs. The concentration of all miRNAs was 100 pM. When the single-base mismatched miRNAs (miR141 A, B and miR375 A, B) were present, featureless SERS signals were obtained from the PNI sensors. In contrast, significantly strong SERS signals were measured from the PNI sensors in the presence of miR141 and miR375 with intact sequences. In the miRNA sensing procedure using the PNI sensor, the unstable single-base mismatched miRNA–LNA hybridized structures were destroyed at the temperature over T_m. Therefore, we near-perfectly excluded the possibility of detecting single-base mismatched miRNAs.

Detection of miRNAs released from cells in culture
The PNI sensors were also employed to detect miR141 and miR375 released from the living PC cells. We prepared four types of media in which different human cancer cell lines were cultured. The cultured cell lines were LNCaP (PC cells), PC-3 (PC cells), RWPE-1 (noncancerous prostate epithelial cells), and HeLa (cervical cancer cells). For the detection of miR141 and miR375 using PNI sensors, the total extracellular miRNA released from the cells into the media were isolated and purified. Figure 2(a,b) represent the extracellular miR141 and miR375 levels determined by the PNI sensor for LNCaP, PC-3, RWPE-1, and HeLa, respectively. The levels of miR141 and miR375 in LNCaP and PC-3 culture supernatants were higher than those in RWPE-1 and HeLa, indicating that the PNI sensor can detect extracellular miRNAs released from living PC cells accurately. The well-defined PNI nanostructure which provides a highly reproducible SERS hot spot line, straightforward probe LNA immobilization, and simple miRNA–LNA hybrid formation with equalized stabilities seems to collectively contribute to the observed equally enhanced and highly reproducible SERS signals for miR141 and miR375.

Conclusion
We have developed a PNI sensor that can detect extracellular miR141 and miR375 released from the cultured cells of PC cell lines. The proposed PNI sensor exhibited a low detection limit of 100 aM, a wide dynamic range from 100 aM to 100 pM, and a perfect discrimination of single-base mismatches in target miRNAs. By using the PNI sensor, we were able to estimate the absolute amount of the released miR141 and miR375 from each PC cell line. The highly sensitive and exactly quantifiable PNI sensor could be useful for the precise diagnosis of PC patients and will be further valuable for detecting other disease-related extracellular miRNAs.

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The authors
Taejoon Kang*¹ PhD, Bongsoo Kim*² PhD
¹Hazards Monitoring Bionano Research Center, KRIBB, Daejeon 34141, Republic of Korea
²Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea

*Corresponding author
E-mail: kangtaejoon@kribb.re.kr;
bongsoo@kaist.ac.kr

CTC-derived AR-V7 detection as a prognostic and predictive biomarker in advanced prostate cancer
^{Bastos DA, Antonarakis ES. Expert Rev Mol Diagn 2018; 18(2): 155–163}

Prostate cancer is a highly heterogeneous disease, with remarkably different prognosis across all stages. Increased circulating tumour cell (CTC) count (≥5) using the CellSearch assay has been identified as one of the markers that can be used to predict survival, with added value beyond currently available prognostic factors. Recently, androgen receptor splice variant 7 (AR-V7) detection has been associated with worse outcomes for patients with castration-resistant prostate cancer (CRPC) treated with novel androgen receptor-signalling (ARS) inhibitors such as abiraterone and enzalutamide but not taxane chemotherapies. Areas covered: In this manuscript, the authors review the available biomarkers in CRPC and discuss emerging data on the value of CTC-derived AR-V7 status to assess prognosis and its potential role to guide treatment selection for patients with advanced prostate cancer. Expert commentary: Current evidence supports AR-V7 status as a prognostic biomarker and also as a potential predictive biomarker for patients with mCRPC. The authors expect that the incorporation of AR-V7 status and other biomarkers (e.g. AR mutations) in the sequential assessment of patients with advanced prostate cancer will lead to a more rational use of available and future therapies, with significant improvements in outcomes for our patients.

Defining a cohort of men who may not require repeat prostate biopsy based on PCA3 score and MRI: The dual negative effect
^{Perlis N, Al-Kasab T, Ahmad A, Goldberg E, Fadak K, Sayid R, et al. J Urol 2017; doi: 10.1016/j.juro.2017.11.07}

PURPOSE: Prostate cancer over diagnosis and overtreatment are concerns for clinicians and policy makers. Multiparametric magnetic resonance imaging and the PCA3 (prostate cancer antigen 3) urine test select for clinically significant cases. We explored how well the tests performed together in with previous biopsies.

MATERIALS AND METHODS: In accordance with ethics committee approval we collected clinicopathological data on all patients in whom a PCA3 test from was done 2011 to June 2016. This included patients on active surveillance for low-risk prostate cancer and those without prostate cancer who had previous negative biopsies and suspicion of occult disease. We explored whether age, prostate-specific antigen, PCA3 score, multiparametric magnetic resonance imaging, digital rectal examination, family history and prostate size would predict clinically significant prostate cancer on repeat biopsy. The negative predictive value of multiparametric magnetic resonance imaging and PCA3 score was calculated.

RESULTS: A total of 470 patients were included in study. The PCA3 score was abnormal at 35 or greater in 32.5 % of cases. In the multivariate model including 154 men only age (OR 1.08, 95 % CI 1.01–1.16), multiparametric magnetic resonance imaging PI-RADS™ (Prostate Imaging-Reporting and Data System) score 4 (OR 16.6, 95 % CI 3.9–70.0) or 5 (OR 28.3, 95 % CI 5.7–138) and PCA3 score (OR 2.9, 95 % CI 1.0–8.8) predicted clinically significant cancer on biopsy. No patient with negative multiparametric magnetic resonance imaging and a normal PCA3 score had clinically significant prostate cancer on biopsy for a negative predictive value of 100 % (p<0.0001).

CONCLUSIONS: In patients with dual negative tests (multiparametric magnetic resonance imaging and PCA3 score) clinically significant prostate cancer was never found on biopsy, which may be unnecessary in this group. This study was limited by its retrospective design, selection bias and lack of cost-effectiveness data.

Quantitative mass spectrometry-based proteomic profiling for precision medicine in prostate cancer
^{Flores-Morales A, Iglesias-Gato D. Front Oncol 2017; 7: 267}

Prostate cancer (PCa) is one of the most frequently diagnosed cancer among men in the western societies. Many PCa patients bear tumours that will not threat their lives if left untreated or if treatment is delayed. Our inability for early identification of these patients has resulted in massive overtreatment. Therefore, there is a great need of finding biomarkers for patient stratification according to prognostic risk; as well as there is a need for novel targets that can allow the development of effective treatments for patients that progress to castration-resistant PCa. Most biomarkers in cancer are proteins, including the widely-used prostate-specific antigen (PSA). Recent developments in mass spectrometry allow the identification and quantification of thousands of proteins and posttranslational modifications from small amounts of biological material, including formalin-fixed paraffin-embedded tissues, and biological fluids. Novel diagnostic and prognostic biomarkers have been identified in tissue, blood, urine, and seminal plasma of PCa patients, and new insights in the ethology and progression of this disease have been achieved using this technology. In this review, we summarize these findings and discuss the potential of this technology to pave the way toward the clinical implementation of precision medicine in PCa.

Biomarkers for prostate biopsy and risk stratification of newly diagnosed prostate cancer patients
^{Loeb S. Urol Pract 2017; 4(4): 315–321}

INTRODUCTION: Many new markers are now available as an aid for decisions about prostate biopsy for men without prostate cancer, and/or to improve risk stratification for men with newly diagnosed prostate cancer.

METHODS: A literature review was performed on currently available markers for use in decisions about prostate biopsy and initial prostate cancer treatment.

RESULTS: Although total prostate-specific antigen cutoffs were traditionally used for biopsy decisions, PSA elevations are not specific. Repeating the PSA test, and adjusting for factors like age, prostate volume and changes over time can increase specificity for biopsy decisions. The Prostate Health Index (phi) and 4K Score are new PSA-based markers that can be offered as second-line tests to decide on initial or repeat prostate biopsy. The PCA3 urine test and ConfirmMDx tissue test are additional options for repeat biopsy decisions. For men with newly diagnosed prostate cancer, genomic tests are available to refine risk classification and may influence treatment decisions.

CONCLUSIONS: Numerous secondary testing options are now available that can be offered to patients deciding whether to undergo prostate biopsy and those with newly diagnosed prostate cancer.

Bidirectional electrochemiluminescence color switch: an application in detecting multimarkers of prostate cancer
^{Wang YZ, Ji SY, Xu HY, Zhao W, Xu JJ, Chen HY. Anal Chem 2018; doi: 10.1021/acs.analchem.8b00014}

A selective excitation of [Ir(df-ppy)₂(pic)] and [Ru(bpy)3]²⁺ through tuning the electrode potential is reported in this work. Bidirectional colour change from blue-green to red could be observed along with increase and decrease of the potential, which was ascribed to the dual-potential excitation property of [Ir(df-ppy)₂(pic)]. Similar to the three-electrode system, selective excitation of ECL could be achieved at the anode of the bipolar electrode (BPE). Both increase and decrease of the faradic reactions at the cathode of the BPE could induce ECL reporting colour at the other pole switched from blue-green to red. We applied a closed BPE device for the bioanalysis of multicolour ECL since the organic solvent containing electrochemiluminophores could be separated from the bioanalytes. On the basis of BPE arrays coupled with the ECL switch, the detection of three biomarkers of prostate cancer, PSA, microRNA-141, and sarcosine were integrated in a same device. The cutoff values of the biomarkers could be recognized directly by the naked eye. Such a device holds great potential in the early diagnosis of prostate cancer.

Molecular biomarkers in the clinical management of prostate cancer
^{Udager AM, Tomlins SA. Cold Spring Harb Perspect Med 2018; doi: 10.1101/cshperspect.a030601}

Prostate cancer, one of the most common non-cutaneous malignancies in men, is a heterogeneous disease with variable clinical outcome. Although the majority of patients harbour indolent tumours that are essentially cured by local therapy, subsets of patients present with aggressive disease or recur/progress after primary treatment. With this in mind, modern clinical approaches to prostate cancer emphasize the need to reduce overdiagnosis and overtreatment via personalized medicine. Advances in our understanding of prostate cancer pathogenesis, coupled with recent technologic innovations, have facilitated the development and validation of numerous molecular biomarkers, representing a range of macromolecules assayed from a variety of patient sample types, to help guide the clinical management of prostate cancer, including early detection, diagnosis, prognostication, and targeted therapeutic selection. Herein, we review the current state of the art regarding prostate cancer molecular biomarkers, emphasizing those with demonstrated utility in clinical practice.

Genomic markers in prostate cancer decision making
^{Cucchiara V, Cooperberg MR, Dall’Era M, Lin DW, Montorsi F, Schalken JA, et al. Eur Urol. 2017; doi: 10.1016/j.eururo.2017.10.036}

CONTEXT: Although the widespread use of prostate-specific antigen (PSA) has led to an early detection of prostate cancer (PCa) and a reduction of metastatic disease at diagnosis, PSA remains one of the most controversial biomarkers due to its limited specificity. As part of emerging efforts to improve both detection and management decision making, a number of new genomic tools have recently been developed.

OBJECTIVE: This review summarizes the ability of genomic biomarkers to recognize men at high risk of developing PCa, discriminate clinically insignificant and aggressive tumours, and facilitate the selection of therapies in patients with advanced disease.

EVIDENCE ACQUISITION: A PubMed-based literature search was conducted up to May 2017. The most recent and relevant original articles and clinical trials that have provided indispensable information to guide treatment decisions were selected.

EVIDENCE SYNTHESIS: Genome-wide association studies have identified several genetic polymorphisms and inherited variants associated with PCa susceptibility. Moreover, the urine-based assays SelectMDx, Mi-Prostate Score, and ExoDx have provided new insights into the identification of patients who may benefit from prostate biopsy. In men with previous negative pathological findings, Prostate Cancer Antigen 3 and ConfirmMDx predicted the outcome of subsequent biopsy. Commercially available tools (Decipher, Oncotype DX, and Prolaris) improved PCa risk stratification, identifying men at the highest risk of adverse outcome. Furthermore, other biomarkers could assist in treatment selection in castration-resistant PCa. AR-V7 expression predicts resistance to abiraterone/enzalutamide, while poly(ADP-ribose) polymerase-1 inhibitor and platinum-based chemotherapy could be indicated in metastatic patients who are carriers of mutations in DNA mismatch repair genes.

CONCLUSIONS: Introduction of genomic biomarkers has dramatically improved the detection, prognosis, and risk evaluation of PCa. Despite the progress made in discovering suitable biomarker candidates, few have been used in a clinical setting. Large-scale and multi-institutional studies are required to validate the efficacy and cost utility of these new technologies.

PATIENT SUMMARY: Prostate cancer is a heterogeneous disease with a wide variability. Genomic biomarkers in combination with clinical and pathological variables are useful tools to reduce the number of unnecessary biopsies, stratify low-risk from high-risk tumours, and guide personalized treatment decisions.

The use of biomarkers in prostate cancer screening and treatment
^{Ashley VA, Joseph MB, Kamlesh KY, Shalini SY, Ashutosh KT, Joseph R. Rev Urol 2017; 19(4): 221–234}

Prostate cancer screening and diagnosis has been guided by prostate-specific antigen levels for the past 25 years, but with the most recent US Preventive Services Task Force screening recommendations, as well as concerns regarding overdiagnosis and overtreatment, a new wave of prostate cancer biomarkers has recently emerged. These assays allow the testing of urine, serum, or prostate tissue for molecular signs of prostate cancer, and provide information regarding both diagnosis and prognosis. In this review, we discuss 12 commercially available biomarker assays approved for the diagnosis and treatment of prostate cancer. The results of clinical validation studies and clinical decision-making studies are presented. This information is designed to assist urologists in making clinical decisions with respect to ordering and interpreting these tests for different patients. There are numerous fluid and biopsy-based genomic tests available for prostate cancer patients that provide the physician and patient with different information about risk of future disease and treatment outcomes. It is important that providers be able to recommend the appropriate test for each individual patient; this decision is based on tissue availability and prognostic information desired. Future studies will continue to emphasize the important role of genomic biomarkers in making individualized treatment decisions for prostate cancer patients.

A four-kallikrein panel and β-microseminoprotein in predicting high-grade prostate cancer on biopsy: an independent replication from the Finnish Section of the European Randomized Study of Screening for Prostate Cancer
^{Assel M, Sjöblom L, Murtola TJ, Talala K, Kujala P, Stenman UH, et al. Eur Urol Focus 2017; doi: 10.1016/j.euf.2017.11.002}

BACKGROUND: A panel of four kallikrein markers (total, free, and intact prostate-specific antigen [PSA] and human kallikrein-related peptidase 2 [hK2]) improves predictive accuracy for Gleason score ≥7 (high-grade) prostate cancer among men biopsied for elevated PSA. A four-kallikrein panel model was originally developed and validated by the Dutch centre of the European Randomized Study of Screening for Prostate Cancer (ERSPC). The kallikrein panel is now commercially available as 4Kscore™.

OBJECTIVE: To assess whether these findings could be replicated among participants in the Finnish section of ERSPC (FinRSPC) and whether β-microseminoprotein (MSP), a candidate prostate cancer biomarker, adds predictive value.

DESIGN, SETTING, AND PARTICIPANTS: Among 4861 biopsied screening-positive participants in the first three screening rounds of FinRSPC, a case-control subset was selected that included 1632 biopsy-positive cases matched by age at biopsy to biopsy-negative controls.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The predictive accuracy of prespecified prediction models was compared with biopsy outcomes.

RESULTS AND LIMITATIONS: Among men with PSA of 4.0–25 ng/ml, 1111 had prostate cancer, 318 of whom had high-grade disease. Total PSA and age predicted high-grade cancer with an area under the curve of 0.648 (95 % confidence interval [CI] 0.614–0.681) and the four-kallikrein panel increased discrimination to 0.746 (95 % CI 0.717–0.774). Adding MSP to the four-kallikrein panel led to a significant (Wald test; p=0.015) but small increase (0.003) in discrimination. Limitations include a risk of verification bias among men with PSA of 3.0–3.99 ng/ml and the absence of digital rectal examination results.
CONCLUSIONS: These findings provide additional evidence that kallikrein markers can be used to inform biopsy decision making. Further studies are needed to define the role of MSP.

PATIENT SUMMARY: Four kallikrein markers and β-microseminoprotein in blood improve discrimination of high-grade prostate cancer at biopsy in men with elevated prostate-specific antigen.

Combinations of elevated tissue miRNA-17-92 cluster expression and serum prostate-specific
antigen as potential diagnostic biomarkers for prostate cancer
^{Feng S, Qian X, Li H, Zhang X. Oncol Lett 2017; 14(6): 6943–6949}

The aim of the present study was to investigate the effectiveness of the miR-17-92 cluster as a disease progression marker in prostate cancer (PCa). Reverse transcription-quantitative polymerase chain reaction analysis was used to detect the microRNA (miR)-17-92 cluster expression levels in tissues from patients with PCa or benign prostatic hyperplasia (BPH), in addition to in PCa and BPH cell lines. Spearman correlation was used for comparison and estimation of correlations between miRNA expression levels and clinicopathological characteristics such as the Gleason score and prostate-specific antigen (PSA). Receiver operating curve (ROC) analysis was performed for evaluation of specificity and sensitivity of miR-17-92 cluster expression levels for discriminating patients with PCa from patients with BPH. Kaplan-Meier analysis was plotted to investigate the predictive potential of miR-17-92 cluster for PCa biochemical recurrence. Expression of the majority of miRNAs in the miR-17-92 cluster was identified to be significantly increased in PCa tissues and cell lines. Bivariate correlation analysis indicated that the high expression of unregulated miRNAs was positively correlated with Gleason grade, but had no significant association with PSA. ROC curves demonstrated that high expression of miR-17-92 cluster predicted a higher diagnostic accuracy compared with PSA. Improved discriminating quotients were observed when combinations of unregulated miRNAs with PSA were used. Survival analysis confirmed a high combined miRNA score of miR-17-92 cluster was associated with shorter biochemical recurrence interval. miR-17-92 cluster could be a potential diagnostic and prognostic biomarker for PCa, and the combination of the miR-17-92 cluster and serum PSA may enhance the accuracy for diagnosis of PCa.


Prostate-specific antigen screening impacts on biochemical recurrence in patients with clinically localized prostate cancer
^{Hashimoto T, Ohori M, Shimodaira K, Kaburaki N, Hirasawa Y, Satake N, Gondo T, Nakagami Y, Namiki K, Ohno Y. Int J Urol 2018; doi: 10.1111/iju.13563}

OBJECTIVE: To clarify the impact of prostate-specific antigen screening on surgical outcomes of prostate cancer.

METHODS: Patients who underwent radical prostatectomy were divided into two groups according to prostate-specific antigen testing opportunity (group 1, prostate-specific antigen screening; group 2, non-prostate-specific antigen screening). Perioperative clinical characteristics were compared using the Wilcoxon rank-sum and χ2 -tests. Cox proportional hazards models were used to identify independent predictors of postoperative biochemical recurrence-free survival.

RESULTS: In total, 798 patients (63.2 %) and 464 patients (36.8 %) were categorized into groups 1 and 2, respectively. Group 2 patients were more likely to have a higher prostate-specific antigen level and age at diagnosis and larger prostate volume. Clinical T stage, percentage of positive cores and pathological Gleason score did not differ between the groups. The 5-year biochemical recurrence-free survival rate was 83.9 % for group 1 and 71.0 % for group 2 (p<0.001). On multivariate analysis, prostate-specific antigen testing opportunity (hazard ratio 2.530; p<0.001) was an independent predictive factor for biochemical recurrence after surgery, as well as pathological T stage, pathological Gleason score, positive surgical margin and lymphovascular invasion. Additional analyses showed that prostate-specific antigen screening had a greater impact on biochemical recurrence in a younger patients, patients with a high prostate-specific antigen level, large prostate volume and D’Amico high risk, and patients meeting the exclusion criteria of the Prostate Cancer Research International Active Surveillance study.

CONCLUSIONS: Detection by screening results in favourable outcomes after surgery. Prostate-specific antigen screening might contribute to reducing biochemical recurrence in patients with localized prostate cancer.

The global prevalence of diabetes mellitus is increasing rapidly; affecting 8.8% of the population. The Randox automated immunoturbidimetric HbA1c test offers an improved method for the rapid direct measurement of HbA1c in human blood; which is available for use on the RX modena, RX imola and the RX daytona+.

Introduction to the RX series
The RX series combines robust hardware and intuitive software with a world leading test menu comprising of routine chemistries, specific proteins, lipids, therapeutic drugs, drugs of abuse, antioxidants and diabetes testing and a range of niche tests including the HbA1c assay. The RX series removes the need for a separate HbA1c analyser and allows laboratories to expand their testing capabilities onto one single platform, providing cost savings through consolidation.  Built on three core values- reliability, accuracy and precision, the RX series reduces costly test re-runs and misdiagnosis, offering complete confidence in results. The RX series range of clinical chemistry analysers includes the RX misano, (semi-automated) RX monaco, RX daytona+, RX imola and RX modena.

Background
Diabetes is a global epidemic that affects approximately 271 million people around the world and according to the International Diabetes Federation; it is a figure that is on the rise. Their calculations forecast that diabetes will affect roughly 552 million by the year 2030, highlighting the fundamental need to manage patients with diabetes. The USA is one of the most prominent countries affected by diabetes when analysing its prevalence worldwide. It affects roughly 24 million Americans which is a stark contrast to the UK where around 3.5 million people have been diagnosed. It is also important to note that serious health complications can result from diabetes over time which reinforces the need to test HbA1c levels to evaluate how well diabetes is being controlled. The longer you have diabetes, the higher the risk of complications. These can include cardiovascular disease, nerve damage and kidney damage; including end-stage kidney disease which can require dialysis or a kidney transplant. With the rising figures and growing list of complications associated with the disease, diabetes remains one of the leading causes of death in the world and the seventh leading cause of death in the US.

HbA1c explained further
HbA1c, also known as hemoglobin A1c or glycated hemoglobin, is an important blood test that is able to determine how well diabetes is being controlled. It develops when hemoglobin, a protein within red blood cells that carries oxygen throughout the body, joins with glucose in the blood, becoming ‘glycated’. As glycation is irreversible, HbA1c remains in the same state in the red blood cell for 8-12 weeks; giving an overall picture of what the average blood sugar level is. This is particularly important as it allows clinicians to monitor the ‘glycemic’ control in individuals with diabetes.

What is the HbA1c assay used for?
The concentration of HbA1c in the blood of diabetic patients increases with rising blood glucose levels and is representative of the mean blood glucose level over the preceding six to eight weeks. HbA1c can therefore be described as a long term indicator of diabetic control unlike blood glucose which is only a short term indicator of diabetic control. It is recommended that HbA1c levels are monitored every three to four months. In patients who have recently changed their therapy or in those who have gestational diabetes it may be beneficial to measure HbA1c levels more frequently, at two to four week intervals. The onset of diabetes, particularly type two diabetes, tends to be gradual and thus proves difficult to diagnose early. With HbA1c clinicians are able to monitor blood glucose levels periodically to deliver accurate and quick results that can improve patient care.

The clinical significance of HbA1c
The measurement of HbA1c is used in the long term monitoring of diabetes mellitus. This assay should not be used in the diagnosis of diabetes mellitus or for day to day glucose monitoring. Diabetes mellitus is a disease associated with poor glycemic control. Numerous clinical studies, including the Diabetes Control and Complications Trial, have shown that diabetes-related complications may be reduced by the long term monitoring and tight control of blood glucose levels. In the diabetic patient where blood glucose levels are abnormally elevated the level of HbA1c also increases, the reason for this is that HbA1c is formed by the non-enzymatic glycation of the N-terminus of the ß-chain of hemoglobin A0.

Randox HbA1c assay features:

• Sample type – suitable for use with whole blood samples
• Latex enhanced immunoassay method – the Randox assay utilizes an immunoassay method making it simple and quick to perform.
• Liquid ready to use reagents – for ease of use and convenience
• Excellent stability – all reagents are stable to expiry date when stored at +2-8ºC or 28 days on board the analyser at approximately 10°C.

Advantages of the RX series clinical chemistry analysers for direct HbA1c testing:

• Fully automated on-board haemolysis function for HbA1c testing
• Continuous loading & STAT sample functionality to enhance productivity in the laboratory- analyser dependant
• Low sample volumes required
• 1200 tests per hour including ISE (RX modena)
• User friendly software
• Low water consumption
• Dual 5 speed stirrers optimized for reach chemistry reaction
• Reagent micropipette with liquid level sensor and crash detection 
• Liquid level sensor, crash, bubble and clot detection

Key benefits of using the RX series clinical chemistry analysers and Randox HbA1c assay
Direct HbA1c testing eliminates the need for the sample incubation step which is required on alternative methods; allowing samples to be to run immediately on the RX series and providing faster and more accurate results when they are needed. The removal of the offline preparation stage increases the recovery times, allowing laboratories to enhance their workflow and also consolidate testing onto one single clinical chemistry platform. Additional benefits of using the RX series in conjunction with the Randox HbA1c assay include having one assay instead of two, which enables quicker calibration; saving the user time and making the overall method simple and quick to perform, setting a new standard in HbA1c determination and patient care.

For further information or for a quotation for the HbA1c test or to enquire about any analyser in the RX series range, please contact marketing@randox.com.

Randox Laboratories Ltd
55 Diamond Rd
Crumlin, Co. Antrim BT29 4QY
UK
www.randox.com