An analysis of a multiple biomarker panel to better predict prostate cancer metastasis after radical prostatectomy.

A plethora of individual candidate biomarkers for predicting biochemical relapse in localized prostate cancer (PCa) have been proposed. Combined biomarkers may improve prognostication, and ensuring validation against more clinically relevant endpoints are required. The Australian PCa Research Centre NSW has contributed to numerous studies of molecular biomarkers associated with biochemical relapse. In the current study, these biomarkers were re-analyzed for biochemical relapse, metastatic relapse and PCa death with extended follow-up. Biomarkers of significance were then used to develop a combined prognostic model for clinical outcomes and validated in a large independent cohort. The discovery cohort (n = 324) was based on 12 biomarkers with a median follow-up of 16 years. Seven biomarkers were significantly associated with biochemical relapse. Three biomarkers were associated with metastases: AZGP1, Ki67 and PML. Only AZGP1 was associated with PCa death. In their individual and combinational forms, AZGP1 and Ki67 as a dual BM signature was the most robust predictor of metastatic relapse (AUC 0.762). The AZPG1 and Ki67 signature was validated in an independent cohort of 347 PCa patients. The dual BM signature of AZGP1 and Ki67 predicted metastasis in the univariable (HR 7.2, 95% CI, 1.6-32; p = 0.01) and multivariable analysis (HR 5.4, 95% CI, 1.2-25; p = 0.03). The dual biomarker signature marginally improved risk prediction compared to AZGP1 alone (AUC 0.758 versus 0.738, p < 0.001). Our findings indicate that biochemical relapse is not an adequate surrogate for metastasis or PCa death. The dual biomarker signature of AZGP1 and Ki67 offers a small benefit in predicting metastasis over AZGP1 alone.

p53 nuclear accumulation as an early indicator of lethal prostate cancer.

BACKGROUND: After radical prostatectomy (RP) for prostate cancer (PC), p53 alterations predict biochemical relapse (BCR), however, recent evidence suggests that metastatic relapse (MR) not BCR is a surrogate for PC specific mortality (PCSM). This updated analysis of a previously published study investigated the association between p53 aberrations, MR and PCSM in men with localised PC. METHODS: Two hundred and seventy-one men with localised PC treated with RP were included. RP specimens stained for p53 by immunohistochemistry were scored as (a) percentage of p53-positive tumour nuclei; and (b) clustering, where ≥12 p53-positive cells within a ×200 power field was deemed 'cluster positive'. Associations between p53 status and clinical outcomes (BCR, MR and PCSM) were evaluated. RESULTS: Increasing percentage of p53-positive nuclei was significantly associated with shorter time to BCR, MR and PCSM (All p < 0.001). Half of the patients were p53 cluster positive. p53 cluster positivity was significantly associated with poorer outcomes at all clinical endpoints (BCR: HR 2.0, 95% CI 1.51-2.65, p < 0.001; MR: HR 4.1, 95% CI 2.02-8.14, p < 0.001; PCSM: HR 12.2, 95% CI 1.6-93; p = 0.016). These associations were independent of other established prognostic variables. CONCLUSIONS: p53 aberrations in radical prostatectomy tissue predict clinically relevant endpoints of MR and PCSM.

Expression of phosphorylated-mTOR during the development of prostate cancer.

BACKGROUND: The PI3K pathway plays a significant role in the progression of prostate cancer (PCa) to an advanced stage. Mouse models suggest that the downstream effector molecule of the PI3K pathway, mTOR, is also important in the development of PCa, where it plays a pivotal role in forming precursor lesions such as high grade prostatic intraepithelial neoplasia (HGPIN). This study was conducted to determine the status of phosphorylated-mTOR (p-mTOR the activated state of mTOR) across the PCa progression model by looking at expression in normal prostate tissue, proliferative inflammatory atrophy (PIA), HGPIN, and PCa. METHODS: Expression of p-mTOR was evaluated by immunohistochemistry on tissue microarrays constructed from 120 archival formalin-fixed paraffin embedded radical prostatectomy tissue specimens. Levels of expression were recorded as the percentage of positive epithelial cells multiplied by the intensity of staining scored as 0-3. RESULTS: p-mTOR expression was found to increase across the progression model with mean staining in non-neoplastic samples of 40 compared to 98 in PIA, 107 in HGPIN, and 136 in cancer (P < 0.001), but without significant increase between HGPIN and PIA. Correlation of high p-mTOR expression with outcome in PCa showed a trend towards worse prognosis, but this was not statistically significant. CONCLUSIONS: This study demonstrates that p-mTOR signaling has a potential role in both the initiation and progression of PCa. These data provide support for further research into the possible use of rapamycin analogues in the treatment of PCa, and raise the possibility that mTOR might be a potential target for chemoprevention.

High Gleason grade carcinoma at a positive surgical margin predicts biochemical failure after radical prostatectomy and may guide adjuvant radiotherapy.

UNLABELLED: Study Type - Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Only 30-35% of patients with positive surgical margins after radical prostatectomy develop recurrent disease. Adjuvant radiotherapy reduces the rate of biochemical relapse or metastasis and improves overall survival after radical prostatectomy. Various pathological factors, such as location and extent of positive margins, have been proposed as possible prognostic factors in men with margin-positive prostate cancer, however, the recent International Society of Urological Pathology consensus meeting in Boston noted that there is limited data on the significance of Gleason grade of the carcinoma at a positive margin. The present study shows that the presence of high grade prostate cancer, i.e. Gleason pattern 4 or 5, at a positive surgical margin is an independent predictor of biochemical recurrence after radical prostatectomy. Moreover, patients with lower grade carcinoma at the margin have a similar prognosis to men with negative margins. Hence, assessment of Gleason grade at the site of positive margin may aid optimal selection of patients for adjuvant radiotherapy. OBJECTIVE: • To establish predictors of biochemical recurrence by analysing the pathological characteristics of positive surgical margins (PSMs), including Gleason grade of the carcinoma at the involved margin. PATIENTS AND METHODS: • Clinicopathological and outcome data on 940 patients who underwent radical prostatectomy (RP) between 1997 and 2003 were collected. • Of these, 285 (30.3%) patients with PSMs were identified for pathological review, including assessment of location of margin, linear extent, number of PSMs, plane of margin and Gleason grade (3 vs 4 or 5) at the margin. RESULTS: • At a median follow-up of 82 months, the biochemical recurrence rate of the PSM cohort was 29%. • On univariate analysis, the presence of Gleason grade 4 or 5 at the margin (34.4% of cases) was significantly associated with biochemical recurrence (hazard ratio [HR] 2.80, 95% confidence interval [CI]= 1.82-4.32, P < 0.001) compared with the presence of Gleason grade 3. • Linear extent of margin involvement was also associated with recurrence (P= 0.009). • Single vs multiple margin involvement, location, and plane of the involved margin were not significant predictors of recurrence. • On multivariate analysis, Gleason grade 4 or 5 at the margin remained an independent predictor of recurrence (HR 2.14, 95% CI = 1.29-4.03, P= 0.003). CONCLUSION: • The Gleason grade at the site of a PSM identifies patients at increased risk of biochemical recurrence and should aid stratification of patients for adjuvant radiation therapy.

Innovative Methodology for Strengthening a Multidisciplinary Team Approach in Cities in Low- and Middle-Income Countries.

PURPOSE: Delivering high-quality cancer care to patients through a multidisciplinary team (MDT) care approach remains a challenge, particularly in low- and middle-income countries characterized by fragmented health systems and limited human resources for cancer care. City Cancer Challenge (C/Can) is supporting cities in low- and middle-income countries as they work to improve access to equitable quality cancer care. C/Can has developed an innovative methodology to address the MDT gap, piloted in four cities-Asunciòn, Cali, Kumasi, and Yangon. METHODS: Collaborating with a network of partners, C/Can and ASCO have developed a package of technical cooperation support focusing on two priority areas that have emerged as core needs: first developing consensus-based, city-wide patient management guidelines for the most common cancers and second, building capacity for the implementation of MDTs in institutions providing cancer care in the city. RESULTS: The real-time application of C/Can's MDT approach in Cali and Asuncion underlined the importance of engaging the right stakeholders early on and embedding MDT guidelines in local and national regulatory frameworks to achieve their sustainable uptake. The results in Cali and Asuncion were essential for informing the process in Yangon, asserting the clear benefits of city-to-city knowledge exchange. Finally, the global COVID-19 pandemic prompted a rapid adaptation of the methodology from an in-person to virtual format; the unexpected success of the virtual program in Kumasi has led to its application in subsequent C/Can cities. CONCLUSION: The application of C/Can's methodology in this first set of cities has reinforced not only the importance of both resource appropriate guidelines and a highly trained health workforce but also the need for commitment to work across institutions and disciplines.

Low AZGP1 expression predicts for recurrence in margin-positive, localized prostate cancer.

BACKGROUND: Men with positive margins after radical prostatectomy (RP) for localized prostate cancer (PC) have a 40-50% biochemical relapse rate at 5 years. Adjuvant radiotherapy improves biochemical progression-free and overall survival in men with positive margins, but is associated with increased toxicity. There is an urgent need to identify new prognostic markers to define the group of patients who would benefit from multimodality therapy. METHODS: Nuclear ß-catenin, membranous secreted frizzled-related protein 4 (sFRP4), zinc-alpha 2-glycoprotein (AZGP1), and macrophage inhibitory cytokine-1 (MIC-1) have previously been identified as molecular markers of outcome in localized PC. From these published studies, we identified a subset of patients with positive margins. The aim of this study was to assess the association between these four molecular markers and outcome in men with margin-positive, localized PC. RESULTS: We identified 186 men with positive margins from 330 men with localized PC; 53% had preoperative PSA >10 ng/ml, 72% extraprostatic extension (EPE), 24% seminal vesicles involvement (SVI), and 57% RP Gleason score ≥ 7. AZGP1 (P = 0.009), membranous sFRP4 (P = 0.03) and MIC-1 (P = 0.04) expression predicted for biochemical relapse on univariate analysis. Only absent/low AZGP1 expression (P = 0.01) was an independent predictor of recurrence in margin-positive, localized PC when modeled with preoperative PSA (P = 0.2), EPE (P = 0.2), SVI (P = 0.4), Gleason score ≥ 7 (P = 0.5) and adjuvant treatment (P = 0.4). Furthermore, there was an association between absent/low AZGP1 expression and clinical recurrence (P = 0.007). CONCLUSIONS: AZGP1 is a potential molecular marker for biochemical relapse in men with margin-positive, localized PC. Routine assessment of this biomarker may lead to better selection of patients who will benefit from post-RP radiotherapy.

C/Can City Engagement Process: An Implementation Framework for Strengthening Cancer Care in Cities in Low- and Middle-Income Countries.

The effective implementation of locally adapted cancer care solutions in low- and middle-income countries continues to be a challenge in the face of fragmented and inadequately resourced health systems. Consequently, the translation of global cancer care targets to local action for patients has been severely constrained. City Cancer Challenge (C/Can) is leveraging the unique value of cities as enablers in a health systems response to cancer that prioritizes the needs of end users (patients, their caregivers and families, and health care providers). C/Can's City Engagement Process is an implementation framework whereby local stakeholders lead a staged city-wide process over a 2- to 3-year period to assess, plan, and execute locally adapted cancer care solutions. Herein, the development and implementation of the City Engagement Process Framework (CEPF) is presented, specifying the activities, outputs, processes, and indicators across the process life cycle. Lessons learned on the application of the framework in the first so-called Key Learning cities are shared, focusing on the early outputs from Cali, Colombia, the first city to join C/Can in 2017. Creating lasting change requires the creation of a high-trust environment to engage the right stakeholders as well as adapting to local context, leveraging local expertise, and fostering a sustainability mindset from the outset. In the short term, these early learnings inform the refinement of the approach in new cities. Over time, the implementation of this framework is expected to validate the proof-of-concept and contribute to a global evidence base for effective complex interventions to improve cancer care in low- and middle-income countries.

Loss of STARD10 expression identifies a group of poor prognosis breast cancers independent of HER2/Neu and triple negative status.

The phospholipid transfer protein STARD10 cooperates with c-erbB signaling and is overexpressed in Neu/ErbB2 breast cancers. We investigated if STARD10 expression provides additional prognostic information to HER2/neu status in primary breast cancer. A published gene expression dataset was used to determine relationships between STARD10 and HER2 mRNA levels and patient outcome. The central findings were independently validated by immunohistochemistry in a retrospective cohort of 222 patients with breast cancer with a median follow-up of 64 months. Kaplan-Meier and Cox proportional hazards analyses were used for univariate and multivariate analyses. Patients with low STARD10 or high HER2 tumor mRNA levels formed discrete groups each associated with a poor disease-specific survival (p = 0.0001 and p = 0.0058, respectively). In the immunohistochemical study low/absent STARD10 expression i.e. < or = 10% positive cells was observed in 24 of 222 (11%) tumors. In a univariate model, low/absent STARD10 expression was significantly associated with decreased patient survival (p = 0.0008). In multivariate analyses incorporating tumor size, tumor grade, lymph node status, ER, PR and HER2 status, low STARD10 expression was an independent predictor of death from breast cancer (HR: 2.56 (95% CI: 1.27-5.18), p = 0.0086). Furthermore, low/absent STARD10 expression, HER2 amplification and triple negative status were independent prognostic variables. Loss of STARD10 expression may provide an additional marker of poor outcome in breast cancer identifying a subgroup of patients with a particularly adverse prognosis, which is independent of HER2 amplification and the triple negative phenotype.

Expression of S100A2 calcium-binding protein predicts response to pancreatectomy for pancreatic cancer.

BACKGROUND & AIMS: Current methods of preoperative staging and predicting outcome following pancreatectomy for pancreatic cancer (PC) are inadequate. We evaluated the utility of multiple biomarkers from distinct biologic pathways as potential predictive markers of response to pancreatectomy and patient survival. METHODS: We assessed the relationship of candidate biomarkers known, or suspected, to be aberrantly expressed in PC, with disease-specific survival and response to therapy in a cohort of 601 patients. RESULTS: Of the 17 candidate biomarkers examined, only elevated expression of S100A2 was an independent predictor of survival in both the training (n = 162) and validation sets (n = 439; hazard ratio [HR], 2.19; 95% confidence interval [CI]: 1.48-3.25; P < .0001) when assessed in a multivariate model with clinical variables. Patients with high S100A2 expressing tumors had no survival benefit with pancreatectomy compared with those with locally advanced disease, whereas those without high S100A2 expression had a survival advantage of 10.6 months (19.4 vs 8.8 months, respectively) and a HR of 3.23 (95% CI: 2.39-4.33; P < .0001). Of significance, patients with S100A2-negative tumors had a significant survival benefit from pancreatectomy even in the presence of involved surgical margins (median, 15.7 months; P = .0007) or lymph node metastases (median, 17.4 months; P = .0002). CONCLUSIONS: S100A2 expression is a good predictor of response to pancreatectomy for PC and suggests that high S100A2 expression may be a marker of a metastatic phenotype. Prospective measurement of S100A2 expression in diagnostic biopsy samples has potential clinical utility as a predictive marker of response to pancreatectomy and other therapies that target locoregional disease.

Gene based prediction of clinically localized prostate cancer progression after radical prostatectomy.

PURPOSE: Accurate estimates of recurrence risk are needed for optimal treatment of patients with clinically localized prostate cancer. We combined an established nomogram and what to our knowledge are novel molecular predictors into a new prognostic model of prostate specific antigen recurrence. MATERIALS AND METHODS: We analyzed gene expression profiles from formalin fixed, paraffin embedded, localized prostate cancer tissues to identify genes associated with prostate specific antigen recurrence. Profiles of the identified markers were reproduced by reverse transcriptase-polymerase chain reaction. We used the profiles of 3 of these genes along with output from the Kattan postoperative nomogram to produce a predictive model of prostate specific antigen recurrence. RESULTS: After variable selection we built a model of prostate specific antigen recurrence combining expression values of 3 genes and the postoperative nomogram. The 3-gene plus nomogram model predicted 5-year prostate specific antigen recurrence with a concordance index of 0.77 in a validation set compared to a concordance index of 0.67 for the nomogram. This model identified a subgroup of patients at high risk for recurrence that was not identified by the nomogram. CONCLUSIONS: This new gene based classifier has superior predictive power compared to that of the 5-year nomogram to assess the risk of prostate specific antigen recurrence in patients with organ confined prostate cancer. Our classifier should provide more accurate stratification of patients into high and low risk groups for treatment decisions and adjuvant clinical trials.

Activin A is essential for neurogenesis following neurodegeneration.

It has long been proposed that excitotoxicity contributes to nerve cell death in neurodegenerative diseases. Activin A, a member of the transforming growth factor-beta superfamily, is expressed by neurons following excitotoxicity. We show for the first time that this activin A expression is essential for neurogenesis to proceed following neurodegeneration. We found that intraventricular infusion of activin A increased the number of newborn neurons in the dentate gyrus, CA3, and CA1 layers of the normal adult hippocampus and also, following lipopolysaccharide administration, had a potent inhibitory effect on gliosis in vivo and on microglial proliferation in vivo and in vitro. Consistent with the role of activin A in regulating central nervous system inflammation and neurogenesis, intraventricular infusion of follistatin, an activin A antagonist, profoundly impaired neurogenesis and increased the number of microglia and reactive astrocytes following onset of kainic acid-induced neurodegeneration. These results show that inhibiting endogenous activin A is permissive for a potent underlying inflammatory response to neurodegeneration. We demonstrate that the anti-inflammatory actions of activin A account for its neurogenic effects following neurodegeneration because co-administration of nonsteroidal anti-inflammatory drugs reversed follistatin's inhibitory effects on neurogenesis in vivo. Our work indicates that activin A, perhaps working in conjunction with other transforming growth factor-beta superfamily molecules, is essential for neurogenesis in the adult central nervous system following excitotoxic neurodegeneration and suggests that neurons can regulate regeneration by suppressing the inflammatory response, a finding with implications for understanding and treating acute and chronic neurodegenerative diseases.

Stage migration in localized prostate cancer has no effect on the post-radical prostatectomy Kattan nomogram.

OBJECTIVE: To investigate the effect of prostate-specific antigen (PSA) testing on stage migration in an Australian population, and its consequences on the prognostic accuracy of the post-radical prostatectomy (RP) Kattan nomogram, as in North America widespread PSA testing has resulted in prostate cancer stage migration, questioning the utility of prognostic nomograms in this setting. PATIENTS AND METHODS: The study comprised 1008 men who had consecutive RP for localized prostate cancer between 1991 and 2001 at one institution. Two groups were assessed, i.e. those treated in 1991-96 (group 1, the early PSA era), and 1997-2001 (group 2, the contemporary PSA era). Differences in clinicopathological features between the groups were analysed by chi-squared testing and survival modelling. Individual patient data were entered into the post-RP Kattan nomogram and the efficacy assessed by receiver- operating characteristic curve analysis. RESULTS: Patients in group 2 had lower pathological stage disease (P = 0.01) and fewer cancers with Gleason score > or =8 (P < 0.001) than group 1. Multivariate analysis identified preoperative serum PSA level (P < 0.01) and Gleason score (P < 0.01) as strong predictors of biochemical relapse in both groups. In group 2 pathological stage was not significant, but margin involvement became highly significant (P = 0.004). There was no difference in the predictive accuracy of the Kattan nomogram between the groups (P = 0.253). CONCLUSIONS: These findings show a downward stage migration towards organ-confined disease after the introduction of widespread PSA testing in an Australian cohort. Despite this, the Kattan nomogram remains a robust prognostic tool in clinical practice.

HSD17B4 overexpression, an independent biomarker of poor patient outcome in prostate cancer.

Steroid hormones and their metabolising enzymes have been studied extensively for their potential role in prostate cancer, with more recent interest in the androgen/estrogen inactivating enzyme 17beta-hydroxysteroid dehydrogenase type 4 (HSD17B4). Gene expression profiling showed HSD17B4 to be significantly overexpressed in prostate cancer compared to matched-benign epithelium. We therefore hypothesized that altered HSD17B4 expression may contribute to prostate cancer progression via altered hormone balance. In this study, HSD17B4 mRNA and protein expression were assessed by in situ hybridisation (ISH) and immunohistochemistry (IHC), respectively, in tissue arrays of prostate tissue from 172 patients treated by radical prostatectomy. Overexpression of HSD17B4 mRNA and protein was associated with prostate cancer (P<0.0001) and multivariate Cox proportional hazards analysis, adjusted for known prognostic indicators, demonstrated HSD17B4 mRNA and high protein expression were significant independent predictors of poor patient outcome as measured by time until PSA relapse (mRNA: hazards ratio [HR]=1.90, 95% confidence interval [CI]=1.15-3.12; P<0.0001; and protein: HR=2.09, 95% CI=1.31-3.33; P=0.0026). Here we provide strong evidence that both mRNA and protein overexpression of HSD17B4 is not only associated with the presence of prostate cancer, but is also a significant independent predictor of poor patient outcome.

City Cancer Challenge: Changing the Future of Cancer in Urban Populations.

Incidence and mortality from cancer is increasing in most countries in the world, with the highest burden in developing countries. City Cancer Challenge (C/Can), an initiative launched in 2017, aims to improve access to quality cancer care in metropolitan areas (1 million inhabitants or more) in low- and upper-middle income countries by transforming the way stakeholders at the city, regional, and national levels collectively design, plan, and implement local cancer solutions. The approach is built on the core principle that local leaders in cities define their own needs and craft solutions with the support of a network of global, regional, and local partners that reflect an understanding of the unique local context. C/Can aims to build a collective movement of cities that can together deliver quality, equitable, and sustainable cancer control solutions for all.

Androgen regulation of multidrug resistance-associated protein 4 (MRP4/ABCC4) in prostate cancer.

BACKGROUND: MRP4/ABCC4 is an ATP-binding cassette transporter expressed in normal prostate. This study aimed to define the pattern of MRP4/ABCC4 expression in normal and malignant prostate tissue and the relationship of MRP4/ABCC4 expression and function in response to androgen signaling. METHODS: Eighty-four radical prostatectomy specimens from patients with localized prostate cancer (PC) (22 neoadjuvant androgen ablation, AA, 62 no AA), 42 non-cancer and 16 advanced PCs were assessed for MRP4/ABCC4 mRNA/protein expression. The effect of DHT and bicalutamide on LNCaP cells was assessed by immunoblotting. HEK293 cells (+/-MRP4/ABCC4) were assessed for the ability to efflux androgens and anti-androgens. RESULTS: MRP4/ABCC4 mRNA/protein levels were higher in localized PC compared to non-cancer (P = 0.006). MRP4/ABCC4 levels were significantly decreased in PCs treated with AA compared to cancers exposed to normal testosterone levels (P < 0.0001). MRP4/ABCC4 expression in normal human tissues was limited to the prostate and the renal tubules. MRP4/ABCC4 protein levels increased in LNCaP cells after DHT which was partially blocked by bicalutamide. However, DHT did not alter the activation of the MRP4/ABCC4 promotor in luciferase reporter assays and testosterone, DHT, flutamide and hydroxy-flutamide were not substrates for MRP4/ABCC4. DISCUSSION: Elevated MRP4/ABCC4 expression is found in malignant compared to benign prostate tissue while lower MRP4/ABCC4 expression is seen after AA. Furthermore, MRP4/ABCC4 is upregulated by androgen and downregulated by anti-androgen treatment in vitro potentially through an indirect mode of action. These data strongly suggest that MRP4/ABCC4 is an androgen-regulated gene important in the progression to PC and may be a potential drug target.

Immunohistochemical level of unsulfated chondroitin disaccharides in the cancer stroma is an independent predictor of prostate cancer relapse.

The glycosaminoglycan chondroitin sulfate is significantly increased in the peritumoral stroma of prostate tumors compared with normal stroma and is an independent predictor of prostate-specific antigen (PSA) relapse following radical prostatectomy. In this study, we determined whether specific alterations in the sulfation pattern of glycosaminoglycan chains in clinically organ-confined prostate cancer are associated with PSA relapse. Immunoreactivity to distinct glycosaminoglycan disaccharide epitopes was assessed by manually scoring the staining intensity in prostate tissues from patients with benign prostatic hyperplasia (n = 19), early-stage cancer (cohort 1, n = 55 and cohort 2, n = 275), and advanced-stage cancer (n = 20). Alterations to glycosaminoglycans in benign and malignant prostate tissues were determined by cellulose acetate chromatography and high-pressure liquid chromatography. Glycosaminoglycan disaccharide epitopes were localized to the peritumoral stroma of clinically localized prostate cancer. The level of immunostaining for unsulfated disaccharides (C0S) in the peritumoral stroma, but not for 4-sulfated (C4S) or 6-sulfated disaccharides (C6S), was significantly associated with the rate of PSA relapse following radical prostatectomy. High levels of C0S immunostaining were determined to be an independent predictor of PSA relapse (1.6-fold, P = 0.020). Advanced-stage prostate cancer tissues exhibited reduced electrophoretic mobility for chondroitin sulfate and increased unsulfated disaccharides when compared with benign prostatic hyperplasia tissues, whereas the sulfated disaccharide levels were unaffected. The level of C0S immunostaining in the peritumoral stroma is an independent determinant of PSA failure in clinically localized prostate cancer. Specific alterations to chondroitin sulfate side chains occurring during tumor development may be a crucial step for disease progression in prostate cancer.

The propeptide mediates formation of stromal stores of PROMIC-1: role in determining prostate cancer outcome.

The extracellular matrix (ECM) is a reservoir of cellular binding proteins and growth factors that are critical for normal cell behavior, and aberrations in the ECM invariably accompany malignancies such as prostate cancer. Carcinomas commonly overexpress macrophage inhibitory cytokine 1 (MIC-1), a proapoptotic and antitumorigenic transforming growth factor-beta superfamily cytokine. Here we show that MIC-1 is often secreted in an unprocessed propeptide containing form. It is variably processed intracellularly, with unprocessed forms being secreted from several tumor lines, including prostate carcinoma lines, PC-3 and LNCaP. Once secreted, only unprocessed proMIC-1 binds ECM, demonstrating for the first time the occurrence of extracellular stores of MIC-1. The propeptide mediates this association via its COOH-terminal 89 amino acids. Xenograft models bearing tumors secreting various engineered forms of MIC-1 show that the propeptide regulates the balance between ECM stores and circulating serum levels of mature MIC-1 in vivo. The absence of propeptide results in approximately 20-fold increase in serum MIC-1 levels. The significance of stromal MIC-1 stores was evaluated in prostate cancer tissue cores, which show major variation in stromal levels of MIC-1. Stromal MIC-1 levels are linked to prostate cancer outcome following radical prostatectomy, with decreasing stromal levels providing an important independent predictor of disease relapse. In low-grade localized prostate cancer (Gleason sum score < or = 6), the level of MIC-1 stromal stores was the best predictor of future relapse when compared with all other clinicopathologic variables. The secretion and ECM association of unprocessed proMIC-1 is likely to play a central role in modulating local bioavailability of MIC-1 which can affect patient outcome in prostate cancer and other epithelial tumors.

EphB4 expression and biological significance in prostate cancer.

Prostate cancer is the most common cancer in men. Advanced prostate cancer spreading beyond the gland is incurable. Identifying factors that regulate the spread of tumor into the regional nodes and distant sites would guide the development of novel diagnostic, prognostic, and therapeutic targets. The aim of our study was to examine the expression and biological role of EphB4 in prostate cancer. EphB4 mRNA is expressed in 64 of 72 (89%) prostate tumor tissues assessed. EphB4 protein expression is found in the majority (41 of 62, 66%) of tumors, and 3 of 20 (15%) normal prostate tissues. Little or no expression was observed in benign prostate epithelial cell line, but EphB4 was expressed in all prostate cancer cell lines to varying degrees. EphB4 protein levels are high in the PC3 prostate cancer cell line and several folds higher in a metastatic clone of PC3 (PC3M) where overexpression was accompanied by EphB4 gene amplification. EphB4 expression is induced by loss of PTEN, p53, and induced by epidermal growth factor/epidermal growth factor receptor and insulin-like growth factor-I/insulin-like growth factor-IR. Knockdown of the EphB4 protein using EphB4 short interfering RNA or antisense oligodeoxynucleotide significantly inhibits cell growth/viability, migration, and invasion, and induces apoptosis in prostate cancer cell lines. Antisense oligodeoxynucleotide targeting EphB4 in vivo showed antitumor activity in murine human tumor xenograft model. These data show a role for EphB4 in prostate cancer and provide a rationale to study EphB4 for diagnostic, prognostic, and therapeutic applications.