Prognostic significance of plasma chromogranin a levels in patients with hormone-refractory prostate cancer treated in Cancer and Leukemia Group B 9480 study

Tissue-Based Diagnostic Biomarkers of Aggressive Variant Prostate Cancer: A Narrative Review

Prostate cancer (PC) is a common malignancy among elderly men, characterized by great heterogeneity in its clinical course, ranging from an indolent to a highly aggressive disease. The aggressive variant of prostate cancer (AVPC) clinically shows an atypical pattern of disease progression, similar to that of small cell PC (SCPC), and also shares the chemo-responsiveness of SCPC. The term AVPC does not describe a specific histologic subtype of PC but rather the group of tumors that, irrespective of morphology, show an aggressive clinical course, dictated by androgen receptor (AR) indifference. AR indifference represents an adaptive response to androgen deprivation therapy (ADT), driven by epithelial plasticity, an inherent ability of tumor cells to adapt to their environment by changing their phenotypic characteristics in a bi-directional way. The molecular profile of AVPC entails combined alterations in the tumor suppressor genes retinoblastoma protein 1 (RB1), tumor protein 53 (TP53), and phosphatase and tensin homolog (PTEN). The understanding of the biologic heterogeneity of castration-resistant PC (CRPC) and the need to identify the subset of patients that would potentially benefit from specific therapies necessitate the development of prognostic and predictive biomarkers. This review aims to discuss the possible pathophysiologic mechanisms of AVPC development and the potential use of emerging tissue-based biomarkers in clinical practice.

Prognostic and predictive analyses of circulating plasma biomarkers in men with metastatic castration resistant prostate cancer treated with docetaxel/prednisone with or without bevacizumab

BACKGROUND

CALGB 90401 (Alliance) was a phase III trial of 1050 patients with metastatic castration-resistant prostate cancer (mCRPC) comparing docetaxel, prednisone, bevacizumab (DP+B) versus DP alone. While this trial did not show an improvement in overall survival (OS), there were improved intermediate outcomes suggesting that subsets of men may derive benefit from this combination. The purpose of this analysis was to identify prognostic and predictive biomarkers associated with OS and progression-free survival (PFS) benefit from DP+B.

METHODS

Baseline EDTA plasma samples from 650 consenting patients were analyzed for 24 biomarkers. The proportional hazards model was utilized to test for the prognostic and predictive importance of the biomarkers for OS. The statistically significant biomarkers of OS were further investigated for prognostic and predictive importance for other secondary outcomes.

RESULTS

15 markers [ICAM-1, VEGF-R3, TIMP-1, TSP-2, Ang-2, Her-3, Osteopontin (OPN), PlGF, VCAM-1, HGF, VEGF, Chromogranin A, IL-6, VEGF-R1, BMP-9] were prognostic of OS, while 9 markers (ICAM-1, VEGF-R3, Her-3, TIMP-1, Ang-2, OPN, PlGF, HGF, and VEGF) were also prognostic of PFS. All markers were statistically significant in univariate analyses after adjustment for multiplicity (FDR < 0.1). In multivariable analyses of OS adjusting for risk score, seven markers had FDR < 0.1, including ICAM-1, VEGF-R3, TIMP-1, Ang-2, VEGF, TSP-2 and HGF. In unadjusted analysis, OPN was predictive of PFS improvement with DP+B, in both univariate and multivariable analysis. However, none of the biomarkers tested were predictive of clinical outcomes after adjusting for multiple comparisons.

CONCLUSIONS

Multiple biomarkers were identified in CALGB 90401 as prognostic of clinical outcomes but not predictive of OS. While OPN may have promise as a potential biomarker for anti-angiogenic therapies, further mechanistic and clinical studies are needed to determine the underlying biology and potential clinical application.

Clinical considerations for the management of androgen indifferent prostate cancer

BACKGROUND

Many systemic therapies for advanced prostate cancer work by disrupting androgen receptor signaling. Androgen indifferent prostate cancer (AIPC) variants, including aggressive variant prostate cancer (AVPC), neuroendocrine prostate cancer (NEPC), and double-negative prostate cancer (DNPC), are increasingly common and often overlapping resistance phenotypes following treatment with androgen receptor signaling inhibitors in men with metastatic castration-resistant prostate cancer and are associated with poor outcomes. Understanding the underlying biology and identifying effective therapies for AIPC is paramount for improving survival for men with prostate cancer.

METHODS

In this review, we summarize the current knowledge on AIPC variants, including our current understanding of the clinical, morphologic, and molecular features as well as current therapeutic approaches. We also explore emerging therapies and biomarkers aimed at improving outcomes for men with AIPC.

RESULTS AND CONCLUSIONS

Establishing consensus definitions, developing novel biomarkers for early and accurate detection, further characterization of molecular drivers of each phenotype, and developing effective therapies will be critical to improving outcomes for men with AIPC. Significant progress has been made toward defining the clinical and molecular characteristics of AVPC, NEPC, and DNPC. Novel diagnostic approaches, including cell-free DNA, circulating tumor cells, and molecular imaging are promising tools for detecting AIPC in clinical practice. Building on previous treatment advances, several clinical trials are underway evaluating novel therapeutic approaches in patients with AIPC informed by an understanding of variant-specific biology. In this review, we discuss how these recent and ongoing studies will help to improve diagnosis, prognosis, and therapy for men with AIPC.

Association between lactate dehydrogenase levels and oncologic outcomes in metastatic prostate cancer: A meta-analysis

Purpose

Previous studies have provided evidence of the high expression of lactate dehydrogenase (LDH) in multiple solid tumors; however, its prognostic relationship with metastatic prostate cancer (mPCa) remains controversial. We performed a meta‐analysis to better understand the prognostic potential of LDH in mPCa.

Methods

In our investigation, we included PubMed, Embase, Web of Science, and Cochrane Library as web‐based resources, as well as studies published before January 2020 on the predictive value of LDH in mPCa. We independently screened the studies according to the inclusion and exclusion criteria, evaluated the quality of the literature, extracted the data, and used RevMan 5.3 and STATA12.0 software for analysis.

Result

From the 38 published studies, the records of 9813 patients with mPCa were included in this meta‐analysis. We observed that higher levels of LDH in patients with mPCa were significantly associated with poorer overall survival (OS) (HR = 2.17, 95% CI: 1.91‐2.47, P < .00001) and progression‐free survival (PFS) (HR = 1.60, 95% CI: 1.20‐2.13, P = .001). The subgroup analyses indicated that the negative prognostic impact of higher levels of LDH on the oncologic outcomes of mPCa was significant regardless of ethnicity, publication year, sample size, analysis type, treatment type, age, and disease state.

Conclusion

Our analysis suggested the association between a higher level of LDH and poorer OS and PFS in patients with mPCa. As a parameter that can be conveniently evaluated, the LDH levels should be included as a valuable biomarker in the management of mPCa.

Response Prediction of 177Lu-PSMA-617 Radioligand Therapy Using Prostate-Specific Antigen, Chromogranin A, and Lactate Dehydrogenase

Neuroendocrinelike transdifferentiation of prostate cancer adenocarcinomas correlates with serum levels of chromogranin A (CgA) and drives treatment resistance. The aim of this work was to evaluate whether CgA can serve as a response predictor for ¹⁷⁷Lu-prostate-specific membrane antigen 617 (PSMA) radioligand therapy (RLT) in comparison with the established tumor markers. Methods: One hundred consecutive patients with metastasized castration-resistant prostate cancer scheduled for PSMA RLT were evaluated for prostate-specific antigen (PSA), lactate dehydrogenase (LDH), and CgA at baseline and in follow-up of PSMA RLT. Tumor uptake of PSMA ligand, a known predictive marker for response, was assessed as a control variable. Results: From the 100 evaluated patients, 35 had partial remission, 16 stable disease, 15 mixed response, and 36 progression of disease. Tumor uptake above salivary gland uptake translated into partial remission, with an odds ratio (OR) of 60.265 (95% confidence interval [CI], 5.038-720.922). Elevated LDH implied a reduced chance for partial remission, with an OR of 0.094 (95% CI, 0.017-0.518), but increased the frequency of progressive disease (OR, 2.717; 95% CI, 1.391-5.304). All patients who achieved partial remission had a normal baseline LDH. Factor-2 elevation of CgA increased the risk for progression, with an OR of 3.089 (95% CI, 1.302-7.332). Baseline PSA had no prognostic value for response prediction. Conclusion: In our cohort, baseline PSA had no prognostic value for response prediction. LDH was the marker with the strongest prognostic value, and elevated LDH increased the risk for progression of disease under PSMA RLT. Elevated CgA demonstrated a moderate impact as a negative prognostic marker in general but was explicitly related to the presence of liver metastases. Well in line with the literature, sufficient tumor uptake is a prerequisite to achieve tumor response.

Prognostic role of chromogranin A in castration-resistant prostate cancer: A meta-analysis

We aimed to investigate the prognostic value of chromogranin A (CgA) in castration-resistant prostate cancer (CRPC). We conducted a systematic literature search of PubMed, Web of Science, and EMBASE for citations published prior to September 2017 that described CgA and CRPC and performed a standard meta-analysis on survival outcomes. Our meta-analysis included eight eligible studies with 686 patients. The results were as follows: progression-free survival (PFS) was associated with CgA level (hazard ratio [HR] = 2.47, 95% confidence interval [CI]: 1.47-4.14, P = 0.0006); PFS was relative to CgA change (HR = 9.22, 95% CI: 3.03-28.05, P < 0.0001); and overall survival (OS) was relative to CgA level (HR = 1.47, 95% CI: 1.15-1.87, P = 0.002). When we divided the patients into two groups according to therapy status, the result for OS relative to CgA level was an HR of 1.26 (95% CI: 1.09-1.45, P = 0.001) in the first-line hormonal therapy group, and an HR of 2.33 (95% CI: 1.40-3.89, P = 0.001) in the second-line hormonal therapy or chemotherapy group. This meta-analysis indicated that a high CgA level had a negative influence on OS and PFS in CRPC patients. In addition, CRPC patients with a rising CgA had a shorter PFS. Further studies are needed to verify the prognostic value of CgA in CRPC.

[Neuroendocrine prostate cancer]

Neuroendocrine prostate cancer (NEPC) mostly occurs as a treatment-emergent adaptive response under the pressure of intensive androgen deprivation treatment (t-NEPC). Approximately 30-40% of patients with metastatic castration-resistant prostate cancer (mCRPC) also have neuroendocrine involvement. In contrast primary small cell prostate cancer is very rare (<1%). A t‑NEPC should be clinically suspected in patients who have particularly aggressive mCRPC but a disproportionately low prostate-specific antigen (PSA) level and elevated neuroendocrine tumor markers, such as chromogranin A and neuron-specific enolase. The initial Gleason score was shown to be an independent factor correlated to the risk of development of t‑NEPC. Treatment is oriented to that of small cell lung cancer. In patients with negative PSA levels, chemotherapy with cisplatin and etoposide is the first line treatment, for which response rates in the range of 30-60% with a median survival time of usually less than 1 year can be achieved. In patients with much higher serum PSA levels, chemotherapy with carboplatin plus docetaxel should be considered.

Prognostic Value of Lactate Dehydrogenase in Metastatic Prostate Cancer: A Systematic Review and Meta-analysis

The purpose of this study was to assess the prognostic value of lactate dehydrogenase (LDH) in patients with metastatic prostate cancer (PC). A systematic review and meta-analysis was performed in March 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. Studies were deemed eligible if they compared patients with PC with high versus low LDH to determine the predictive value of LDH for overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS). We performed a formal meta-analysis for both OS and PFS. A total of 59 articles with 14,851 patients were included in the systematic review and 45 studies with 12,224 patients for the qualitative assessment. High LDH was associated with both worse OS (pooled hazard ratio [HR], 2.07; 95% confidence interval [CI], 1.75-2.44) and PFS (pooled HR, 1.08; 95% CI, 1.01-1.16). In subgroup analyses of both patients with castration-resistant prostate cancer (CRPC) and those with hormone-sensitive prostate cancer (HSPC), LDH was associated with OS (pooled HR, 2.02; 95% CI, 1.69-2.42 and pooled HR, 2.25; 95% CI, 1.78-2.84, respectively). In patients with CRPC, LDH was associated with OS in those treated with docetaxel systemic chemotherapy and androgen receptor-axis-targeting agents (pooled HR, 2.03; 95% CI, 1.37-3.00 and pooled HR, 1.79; 95% CI, 1.25-2.57, respectively). Elevated serum levels of LDH were associated with an increased risk of mortality and progression in patients with metastatic PC. LDH was independently associated with OS in both patients with CRPC and HSPC. LDH could be integrated into prognostic tools that help guide treatment strategy, thereby facilitating the shared decision-making process.

Neuroendocrine differentiation of prostatic adenocarcinoma – an important cause for castration-resistant disease recurrence

Background

Neuroendocrine differentiation of prostatic carcinoma is a rare entity associated with metastatic castration-resistant disease. Among useful biomarkers of neuroendocrine differentiation, chromogranin A, serotonin, synaptophysin and neuron-specific enolase stand out, while total prostate-specific antigen (PSA) levels are often low or undetectable.

Case presentation

We report a case of prostatic adenocarcinoma recurrence after a 6-year disease-free follow-up, in which increased serum chromogranin A levels and undetectable total PSA provided a prompt indication of neuroendocrine transformation, confirmed through immunohistochemical evaluation.

Conclusions

Neuroendocrine differentiation is a relevant cause of prostatic adenocarcinoma recurrence, and awareness of this entity is crucial due to its underdiagnosis and adverse prognosis.

Chromogranin A is a predictor of prognosis in patients with prostate cancer: a systematic review and meta-analysis

Background: The prognostic value of chromogranin-A (CHGA) as a biomarker of prostate cancer (PCa) has been evaluated extensively. However, to date the results still remain controversial. This study aims to perform a meta-analysis on previous studies in order to determine whether CHGA would be a biomarker for survival in PCa patients. Methods: MEDLINE, Embase, Web of Science, and Cochrane Library databases were searched to identify eligible studies published before September 2018, regarding the association of CHGA gene expression with survival outcomes in patients with PCa. Multivariate adjusted HRs and associated 95% CIs were calculated using random effects models. Results: Ten cohort studies involving 3,172 patients were finally included. According to the included studies, circulating CHGA levels were tested in serum, plasma, and tissues. The results showed an association between high CHGA expression and worse overall survival (OS) (HR=1.24, 95% CI: 1.07-1.44; P=0.004; I ²=77.6%) in PCa patients. However, no significant association was observed between increasing CHGA expression and shorter progression-free survival (HR=1.73, 95% CI: 0.92-3.28; P=0.090; I ²=73.9%). The results of sensitivity analysis validated the rationality and reliability of our analysis. Conclusion: Current evidence indicates that high CHGA expression is a potential marker for poor OS in PCa. Future studies are needed to explore tailored treatments that directly target CHGA for the improvement of survival in men with PCa.

Neuroendocrine differentiation in castration resistant prostate cancer. Nuclear medicine radiopharmaceuticals and imaging techniques: A narrative review

BACKGROUND

Androgen Deprivation Therapy (ADT) is the primary treatment for patients suffering from relapsing or advanced prostate cancer (PC). Hormone therapy generally guarantees adequate clinical control of the disease for some years, even in those patients affected by widespread skeletal and soft tissue metastases. Despite ADT, however, most patients treated with hormones eventually progress to castration-resistant prostate cancer (CRPC), for which there are no effective treatments. This clinical reality is an open challenge to the oncologist because of those neoplasms which elaborate neuroendocrine differentiation (NED).

METHODS

An online search of current and past literature on NED in CRPC was performed. Relevant articles dealing with the biological and pathological basis of NED, with nuclear medicine imaging in CRPC and somatostatin treatment in NED were analyzed.

EVIDENCE FROM THE LITERATURE

NED may arise in prostate cancer patients in the late stages of ADT. The onset of NED offers prognostic insight because it reflects a dramatic increase in the aggressive nature of the neoplasm. Several genetic, molecular, cytological and immunohistochemical markers are associated with this transformation. Among these, overexpression of somatostatin receptors, seen through Nuclear Medicine testing, is one of the most studied.

CONCLUSIONS

Preliminary studies show that the overexpression of somatostatin receptors related to NED in CRPC may easily be studied in vivo with PET/CT. This finding offers a potentially useful objective for targeted therapy in CRPC. If the overexpression of SSTRs is shown to afflict a significant segment of patients with CRPC, this will open further study of possible therapeutic options based on this marker.

[Neuroendocrine prostate cancer]

Neuroendocrine prostate cancer (NEPC) mostly occurs as a treatment-emergent adaptive response under the pressure of intensive androgen deprivation treatment (t-NEPC). Approximately 30-40% of patients with metastatic castration-resistant prostate cancer (mCRPC) also have neuroendocrine involvement. In contrast primary small cell prostate cancer is very rare (<1%). A t‑NEPC should be clinically suspected in patients who have particularly aggressive mCRPC but a disproportionately low prostate-specific antigen (PSA) level and elevated neuroendocrine tumor markers, such as chromogranin A and neuron-specific enolase. The initial Gleason score was shown to be an independent factor correlated to the risk of development of t‑NEPC. Treatment is oriented to that of small cell lung cancer. In patients with negative PSA levels, chemotherapy with cisplatin and etoposide is the first line treatment, for which response rates in the range of 30-60% with a median survival time of usually less than 1 year can be achieved. In patients with much higher serum PSA levels, chemotherapy with carboplatin plus docetaxel should be considered.

Plasma androgen receptor and serum chromogranin A in advanced prostate cancer

Recently, mixed forms between adenocarcinoma and neuroendocrine prostate cancer (NEPC) have emerged that are characterized by persistent androgen receptor (AR)-signalling and elevated chromogranin A (CgA) levels. The main aim of this study was to analyze castration-resistant prostate cancer (CRPC) patients treated with abiraterone or enzalutamide, assessing progression-free/overall survival (PFS/OS) in association with circulating AR and CgA. AR aberrations were analyzed by droplet digital PCR in pre-treatment plasma samples collected from two biomarker protocols [197 patients from a retrospective study (REC 2192/2013) and 59 from a prospective trial (REC 6798/2015)]. We subdivided patients into three groups according to CgA by receiver-operating characteristic (ROC) curves. In the primary cohort, plasma AR gain and mutations (p.L702H/p.T878A) were detected in 78 (39.6%) and 16 (8.1%) patients, respectively. We observed a significantly worse PFS/OS in patients with higher-CgA than in patients with normal-CgA, especially those with no AR-aberrations. Multivariable analysis showed AR gain, higher-CgA and LDH levels as independent predictors of PFS [hazard ratio (HR) = 2.16, 95% confidence interval (95% CI) 1.50-3.12, p < 0.0001, HR = 1.73, 95% CI 1.06-2.84, p = 0.026, and HR = 2.13, 95% CI 1.45-3.13, p = 0.0001, respectively) and OS (HR = 1.72, 95% CI 1.15-2.57, p = 0.008, HR = 3.63, 95% CI 2.13-6.20, p < 0.0001, and HR = 2.31, 95% CI 1.54-3.48, p < 0.0001, respectively). These data were confirmed in the secondary cohort. Pre-treatment CgA detection could be useful to identify these mixed tumors and would seem to have a prognostic role, especially in AR-normal patients. This association needs further evaluation in larger prospective cohorts.

Proteogenomic Characterization of Patient-Derived Xenografts Highlights the Role of REST in Neuroendocrine Differentiation of Castration-Resistant Prostate Cancer

PURPOSE

An increasing number of castration-resistant prostate cancer (CRPC) tumors exhibit neuroendocrine (NE) features. NE prostate cancer (NEPC) has poor prognosis, and its development is poorly understood.Experimental Design: We applied mass spectrometry-based proteomics to a unique set of 17 prostate cancer patient-derived xenografts (PDX) to characterize the effects of castration in vivo, and the proteome differences between NEPC and prostate adenocarcinomas. Genome-wide profiling of REST-occupied regions in prostate cancer cells was correlated to the expression changes in vivo to investigate the role of the transcriptional repressor REST in castration-induced NEPC differentiation.

RESULTS

An average of 4,881 proteins were identified and quantified from each PDX. Proteins related to neurogenesis, cell-cycle regulation, and DNA repair were found upregulated and elevated in NEPC, while the reduced levels of proteins involved in mitochondrial functions suggested a prevalent glycolytic metabolism of NEPC tumors. Integration of the REST chromatin bound regions with expression changes indicated a direct role of REST in regulating neuronal gene expression in prostate cancer cells. Mechanistically, depletion of REST led to cell-cycle arrest in G₁, which could be rescued by p53 knockdown. Finally, the expression of the REST-regulated gene secretagogin (SCGN) correlated with an increased risk of suffering disease relapse after radical prostatectomy.

CONCLUSIONS

This study presents the first deep characterization of the proteome of NEPC and suggests that concomitant inhibition of REST and the p53 pathway would promote NEPC. We also identify SCGN as a novel prognostic marker in prostate cancer.

Serum chromogranin-A-based prognosis in metastatic castration-resistant prostate cancer

OBJECTIVE

To determine the prognostic value of serum chromogranin-A (CGA) in a two-cohort study of men with metastatic castrate resistant prostate cancer (mCRPC) and to compare with circulating tumor cells (CTCs)-based prognosis.

PATIENTS AND METHODS

A two-cohort-based evaluation for serum CGA for prognostication in CRPC stage was performed using a screening cohort of 256 men with mCRPC and an independent validation cohort of 92 men with mCRPC. In both cohorts, men receiving proton pump inhibitors and those with non-castrate levels of testosterone (>50 ng/dl) were excluded. Serum CGA was measured in a homogeneous automated immunofluorescent assay using time-resolved amplified cryptate emission. In the validation cohort, CTC enumeration was also performed using the FDA-cleared CELLSEARCH® CTC test. Cox proportional hazard regression models were used for prognostic association of serum CGA and CTC counts with overall survival.

RESULTS

In the screening cohort, 200 men were eligible for analysis. The median serum CGA was 100.3 ng/mL (interquartile range: 67-161.3) and 34/200 were above the reference range. In the subset of men with Gleason scores ≥ 8, elevated CGA was associated with shorter overall survival [hazard ratio (HR) 2.19, p = 0.017]. In the validation cohort for 71 men eligible for analysis, the median serum CGA was 90 ng/mL (interquartile range: 55-156) and 31/71 patients had an elevated CGA. 51% of patients had a Gleason score ≥ 8 and 66/71 patients had CTCs enumerated with 26/66 with a CTC count ≥ 5 per 7.5 ml blood sample (unfavorable). Both elevated serum CGA (HR: 1.91, p = 0.043) and unfavorable CTC counts (HR: 2.97, p = 0.0012) were adversely associated with overall survival and patients with ≥ 5 CTCs and elevated serum CGA had the shortest overall survival (HR: 3.76, p = 0.008).

CONCLUSION

Elevated serum CGA was negatively associated with OS in men with mCRPC. Serum CGA represents a prognostic biomarker that may complement CTC enumeration.

Chromogranin A and neurone-specific enolase serum levels as predictors of treatment outcome in patients with metastatic castration-resistant prostate cancer undergoing abiraterone therapy

OBJECTIVE

To determine the impact of elevated neuroendocrine serum markers on treatment outcome in patients with metastatic castration-resistant prostate cancer (mCRPC) undergoing treatment with abiraterone in a post-chemotherapy setting.

PATIENTS AND METHOD

Chromogranin A (CGa) and neurone-specific enolase (NSE) were determined in serum drawn before treatment with abiraterone from 45 patients with mCRPC. Outcome measures were overall survival (OS), prostate-specific antigen (PSA) response defined by a PSA level decline of ≥50%, PSA progression-free survival (PSA-PFS), and clinical or radiographic PFS.

RESULTS

The CGa and NSE serum levels did not correlate (P = 0.6). Patients were stratified in to low- (nine patients), intermediate- (18) or high-risk (18) groups according to elevation of none, one, or both neuroendocrine markers, respectively. The risk groups correlated with decreasing median OS (median OS not reached vs 15.3 vs 6.6 months; P < 0.001), decreasing median clinical or radiographic PFS (8.3 vs 4.4 vs 2.7 months; P = 0.001) and decreasing median PSA-PFS (12.0 vs 3.2 vs 2.7 months; P = 0.012). In multivariate Cox regression analysis the combination of CGa and NSE (≥1 marker positive vs both markers negative) remained significant predictors of OS, clinical or radiographic PFS, and PSA-PFS. We did not observe a correlation with PSA response (63% vs 35% vs 31%; P = 0.2).

CONCLUSION

Chromogranin A and NSE did not predict PSA response in patients with mCRPC treated with abiraterone. However, we observed a correlation with shorter PSA-PFS, clinical or radiographic PFS, and OS. This might be due to an elevated risk of developing resistance under abiraterone treatment related to neuroendocrine differentiation.

Assessment of anticancer-treatment outcome in patients with metastatic castration-resistant prostate cancer-going beyond PSA and imaging, a systematic literature review

BACKGROUND

In the past years, there has been significant progress in anticancer drug development for patients with metastatic castration-resistant prostate cancer (CRPC). However, the current instruments to assess clinical treatment response have limitations and may not sufficiently reflect patient benefit. Our objective was to systematically identify tools to evaluate both patient benefit and clinical anticancer-treatment response as basis for an international consensus process and development of a specific pragmatic instrument for men with CRPC.

METHODS

PubMed, Embase and CINAHL were searched to identify currently available tools to assess anticancer-treatment benefit, other than standard imaging procedures and prostate-specific antigen measurements, namely quality of life (QoL), detailed pain assessment, physical function and objective measures of other complex cancer-related syndromes in patients with CRPC. Additionally, all CRPC phase III trials published in the last 5 years were reviewed as well as studies using physical function tools in a general cancer population. The PRIMSA statement was followed for the systematic review process.

RESULTS

The search generated 1096 hits, 185 full-text papers were screened and finally 73 publications were included. Additional 89 publications were included by hand-search. We identified a total of 98 tools used in CRPC trials and grouped these into three categories: 22 tools assessing QoL domains and subgroups, 47 tools for pain assessment and 29 tools for objective measures, mainly physical function and assessment of skeletal disease burden.

CONCLUSION

A wide variety of assessment tools and also efforts to standardize and harmonize patient-reported outcomes and pain assessment were identified. However, the specific needs of the increasing CRPC population living longer with their incurable cancer are insufficiently captured and objective physical outcome measures are under-represented. In the age of new anticancer drug targets and principles, new methods to monitor patient relevant outcomes of antineoplastic therapy are of utmost importance.

Prognostic role of lactate dehydrogenase in solid tumors: a systematic review and meta-analysis of 76 studies

BACKGROUND

In cancer cells, metabolism is shifted to aerobic glycolysis with lactate production coupled with a higher uptake of glucose as the main energy source. Lactate dehydrogenase (LDH) catalyzes the reduction of pyruvate to form lactate, and serum level is often raised in aggressive cancer and hematological malignancies. We have assessed the prognostic value of LDH in solid tumors.

MATERIAL AND METHODS

A systematic review of electronic databases was conducted to identify publications exploring the association of LDH with clinical outcome in solid tumors. Overall survival (OS) was the primary outcome, and cancer-specific survival (CSS), progression-free survival (PFS), and disease-free survival (DFS) were secondary outcomes. Data from studies reporting a hazard ratio (HR) and 95% confidence interval (CI) were pooled in a meta-analysis. Pooled HRs were computed and weighted using generic inverse-variance and random-effect modeling. All statistical tests were two-sided.

RESULTS

Seventy-six studies comprising 22 882 patients, mainly with advanced disease, were included in the analysis. Median cut-off of serum LDH was 245 U/L. Overall, higher LDH levels were associated with a HR for OS of 1.7 (95% CI 1.62-1.79; p < 0.00001) in 73 studies. The prognostic effect was highest in renal cell, melanoma, gastric, prostate, nasopharyngeal and lung cancers (all p < 0.00001). HRs for PFS was 1.75 (all p < 0.0001).

CONCLUSIONS

A high serum LDH level is associated with a poor survival in solid tumors, in particular melanoma, prostate and renal cell carcinomas, and can be used as a useful and inexpensive prognostic biomarker in metastatic carcinomas.

Neuroendocrine differentiation in prostate cancer: a mechanism of radioresistance and treatment failure

Neuroendocrine differentiation (NED) in prostate cancer is a well-recognized phenotypic change by which prostate cancer cells transdifferentiate into neuroendocrine-like (NE-like) cells. NE-like cells lack the expression of androgen receptor and prostate specific antigen, and are resistant to treatments. In addition, NE-like cells secrete peptide hormones and growth factors to support the growth of surrounding tumor cells in a paracrine manner. Accumulated evidence has suggested that NED is associated with disease progression and poor prognosis. The importance of NED in prostate cancer progression and therapeutic response is further supported by the fact that therapeutic agents, including androgen-deprivation therapy, chemotherapeutic agents, and radiotherapy, also induce NED. We will review the work supporting the overall hypothesis that therapy-induced NED is a mechanism of resistance to treatments, as well as discuss the relationship between therapy-induced NED and therapy-induced senescence, epithelial-to-mesenchymal transition, and cancer stem cells. Furthermore, we will use radiation-induced NED as a model to explore several NED-based targeting strategies for development of novel therapeutics. Finally, we propose future studies that will specifically address therapy-induced NED in the hope that a better treatment regimen for prostate cancer can be developed.

Prostate cancer and neuroendocrine differentiation: more neuronal, less endocrine?

Neuroendocrine differentiation (NED) marks a structural and functional feature of certain cancers, including prostate cancer (PCa), whereby the malignant tissue contains a significant proportion of cells displaying neuronal, endocrine, or mixed features. NED cells produce, and can secrete, a cocktail of mediators commonly encountered in the nervous system, which may stimulate and coordinate cancer growth. In PCa, NED appears during advanced stages, subsequent to treatment, and accompanies treatment resistance and poor prognosis. However, the term “neuroendocrine” in this context is intrinsically vague. This article seeks to provide a framework on which a unified view of NED might emerge. First, we review the mutually beneficial interplay between PCa and neural structures, mainly supported by cell biology experiments and neurological conditions. Next, we address the correlations between PCa and neural functions, as described in the literature. Based upon the integration of clinical and basic observations, we suggest that it is legitimate to seek for true neural differentiation, or neuromimicry, in cancer progression, most notably in PCa cells exhibiting what is commonly described as NED.

Chromogranin A is a potential prognostic marker in prostate cancer patients treated with enzalutamide

BACKGROUND

In this retrospective study, we assessed chromogranin A (CgA) baseline value as a possible factor associated with poor prognosis in metastatic castration-resistant prostate cancer (CRPC).

METHODS

Thirty-five patients with metastatic CRPC progressing after docetaxel chemotherapy treated with enzalutamide are subdivided into three groups: serum CgA level was normal when <120 ng/ml (group A, n = 10), within three times the upper normal value (UNV) when between 120 and 360 (group B, n = 17), more than three times the UNV when ≥360 ng/ml (group C, n = 8).

RESULTS

No correlation was observed in three groups among CgA baseline values and PSA response rates (RR) (P = 0.4648), whereas a significative difference was associated with median progression-free survival (PFS) and overall survival (OS) among three CgA groups (P = 0.0301 and P = 0.0011, respectively). In the multivariate analysis, PSA RR (nonresponsive vs. responsive) and CgA levels (group 3 vs. groups 1 + 2) were predictors of OS (P = 0.0029 and P = 0.0025, respectively), whereas they only were not significantly correlated with PFS, even had a borderline significance (P = 0.0628 and P = 0.0772, respectively).

CONCLUSIONS

In CRPC patients treated with enzalutamide, the evaluation of serum CgA levels could be an useful prognostic factor because of the strong association between CgA value more than three times the UNV and clinical outcome, independently from PSA response.

Inhibition of NF-kappa B signaling restores responsiveness of castrate-resistant prostate cancer cells to anti-androgen treatment by decreasing androgen receptor-variant expression

Androgen receptor splicing variants (ARVs) that lack the ligand-binding domain (LBD) are associated with the development of castration-resistant prostate cancer (CRPC), including resistance to the new generation of high-affinity anti-androgens. However, the mechanism by which ARV expression is regulated is not fully understood. In this study, we show that the activation of classical nuclear factor-kappa B (NF-κB) signaling increases the expression of ARVs in prostate cancer (PCa) cells and converts androgen-sensitive PCa cells to become androgen-insensitive, whereas downregulation of NF-κB signaling inhibits ARV expression and restores responsiveness of CRPC to anti-androgen therapy. In addition, we demonstrated that combination of anti-androgen with NF-κB-targeted therapy inhibits efficiently tumor growth of human CRPC xenografts. These results indicate that induction of ARVs by activated NF-κB signaling in PCa cells is a critical mechanism by which the PCa progresses to CRPC. This has important implications as it can prolong the survival of CRPC patients by restoring the tumors to once again respond to conventional androgen-deprivation therapy (ADT).

The role of epithelial plasticity in prostate cancer dissemination and treatment resistance

Nearly 30,000 men die annually in the USA of prostate cancer, nearly uniformly from metastatic dissemination. Despite recent advances in hormonal, immunologic, bone-targeted, and cytotoxic chemotherapies, treatment resistance and further dissemination are inevitable in men with metastatic disease. Emerging data suggests that the phenomenon of epithelial plasticity, encompassing both reversible mesenchymal transitions and acquisition of stemness traits, may underlie this lethal biology of dissemination and treatment resistance. Understanding the molecular underpinnings of this cellular plasticity from preclinical models of prostate cancer and from biomarker studies of human metastatic prostate cancer has provided clues to novel therapeutic approaches that may delay or prevent metastatic disease and lethality over time. This review will discuss the preclinical and clinical evidence for epithelial plasticity in this rapidly changing field and relate this to clinical phenotype and resistance in prostate cancer while suggesting novel therapeutic approaches.

Chromogranin A predicts outcome in prostate cancer patients treated with abiraterone

In this retrospective study, we evaluated the chromogranin A (CgA) baseline value as a predictor of clinical outcome in patients with metastatic castration-resistant prostate cancer (CRPC) treated with abiraterone 1000 mg per day, whose disease progressed after docetaxel chemotherapy. In the 48 evaluable patients, serum CgA level was normal when <120  ng/ml (group A, n=16), within three times the upper normal value (UNV) when between 120 and 360 (group B, n=16), more than three times the UNV when ≥360  ng/ml (group C, n=16). Decline in PSA level ≥50% or more (PSA RR) was observed in 26 of 48 (54%) patients. PSA response rate did not correlate with the CgA groups. CgA levels more than three times the UNV predicted an early radiological progressive disease in eight of 11 cases (73%). The median progression-free survival (PFS) among the CgA groups A, B, and C was 9.2, 9.2, and 4.8 months respectively, P=0.0459. The median overall survival (OS) among the CgA groups was 19.0, 18.8, and 10.8 months respectively, P=0.2092. In the multivariate analysis, PSA RR (nonresponsive vs responsive) and CgA levels (group 3 vs groups 1+2) were predictors of PFS (P=0.0002 and P=0.0047 respectively), whereas PSA RR only was significantly associated with OS (P=0.0024), while CgA levels remained of borderline significance (P=0.0919). A serum CGA level more than three times the UNV predicted PFS and showed a trend vs OS prediction, independently from PSA response, in CRPC patients treated with abiraterone.

Prognostic impact of the neutrophil-to-lymphocyte ratio in men with metastatic castration-resistant prostate cancer

BACKGROUND

We retrospectively evaluated the prognostic impact of neutrophil-lymphocyte ratio (NLR) as a marker for inflammatory and immune state in men with progressive metastatic castration resistant prostate cancer (mCRPC) following docetaxel.

METHODS

The SUN-1120 phase III trial comparing prednisone combined with sunitinib (n = 584) or placebo (n = 289) for mCRPC following docetaxel-based chemotherapy was evaluated. The arms were combined for analysis, since no difference was observed in the primary endpoint of overall survival (OS). A logarithmic transformation was applied to non-normal factors. The Kaplan-Meier method was used for OS estimation. To identify an optimal prognostic model for survival, we used a Cox proportional hazards regression method with forward stepwise selection, stratifying for ECOG PS, progression type (prostate specific antigen [PSA] or radiographic) and treatment group. Patients were categorized into risk groups.

RESULTS

Complete data was evaluable for 784 men. The factors used in the model that remained individually significant for OS in multivariable analysis were: log-lactate dehydrogenase level (LDH) level (HR 2.86 [95% CI = 2.29, 3.56], P < .001), hemoglobin (0.80 [0.74, 0.85], P < .001), > 1 organ involved by metastatic disease (1.49 [1.21, 1.84], P < .001), log-alkaline phosphatase (1.13 [0.99, 1.28], P = .074), log-number of prior cycles of docetaxel (0.84 [0.71, 0.98], P = .031), progression on docetaxel (1.35 [1.00, 1.81], P = .049), log-PSA (1.06 [1.00, 1.12], P = .075) and log-NLR (1.55 [1.32, 1.83], P < .001). NLR increased the c-statistic of the prognostic model from 0.703 to 0.715.

CONCLUSION

High NLR may be associated with an independent poor prognostic impact in post-docetaxel patients with mCRPC. These data warrant external validation.

Potential predictive biomarkers for individualizing treatment for men with castration-resistant prostate cancer

With the surge in therapeutic options for men with castration-resistant prostate cancer (CRPC) comes increasingly complicated treatment decision making, highlighting the need for biomarkers that can identify appropriate patients for specific treatments and accurately assess disease response. Predictive biomarkers are factors related to the disease or the host that are associated with improvements in outcomes, such as survival, due to specific therapies. Such biomarkers have become of paramount importance in oncology to maximize the benefits of novel systemic agents while minimizing harm to individual patients and the costs to society. Given the number of newly approved and expensive systemic therapies, including novel hormonal therapies, chemotherapies, immunotherapies, and bone microenvironment-targeting therapies, predictive biomarkers are needed to give physicians a more rational sense of matching the right patient to the right therapy sequence at a given time. There are currently no validated predictive biomarkers in CRPC. We discuss potential predictive biomarkers in men with CRPC and how these may be developed in the context of therapeutic clinical trials.

Platinum-based chemotherapy for variant castrate-resistant prostate cancer

PURPOSE

Clinical features characteristic of small-cell prostate carcinoma (SCPC), "anaplastic," often emerge during the progression of prostate cancer. We sought to determine the efficacy of platinum-based chemotherapy in patients meeting at least one of seven prospectively defined "anaplastic" clinical criteria, including exclusive visceral or predominantly lytic bone metastases, bulky tumor masses, low prostate-specific antigen levels relative to tumor burden, or short response to androgen deprivation therapy.

EXPERIMENTAL DESIGN

A 120-patient phase II trial of first-line carboplatin and docetaxel (CD) and second-line etoposide and cisplatin (EP) was designed to provide reliable clinical response estimates under a Bayesian probability model with early stopping rules in place for futility and toxicity.

RESULTS

Seventy-four of 113 (65.4%) and 24 of 71 (33.8%) were progression free after four cycles of CD and EP, respectively. Median overall survival (OS) was 16 months [95% confidence interval (CI), 13.6-19.0 months]. Of the seven "anaplastic" criteria, bulky tumor mass was significantly associated with poor outcome. Lactic acid dehydrogenase strongly predicted for OS and rapid progression. Serum carcinoembryonic antigen (CEA) concentration strongly predicted OS but not rapid progression. Neuroendocrine markers did not predict outcome or response to therapy.

CONCLUSION

Our findings support the hypothesis that patients with "anaplastic" prostate cancer are a recognizable subset characterized by a high response rate of short duration to platinum-containing chemotherapies, similar to SCPC. Our results suggest that CEA is useful for selecting therapy in men with castration-resistant prostate cancer and consolidative therapies to bulky high-grade tumor masses should be considered in this patient population.

BMI1, stem cell factor acting as novel serum-biomarker for Caucasian and African-American prostate cancer

BACKGROUND

Lack of reliable predictive biomarkers is a stumbling block in the management of prostate cancer (CaP). Prostate-specific antigen (PSA) widely used in clinics has several caveats as a CaP biomarker. African-American CaP patients have poor prognosis than Caucasians, and notably the serum-PSA does not perform well in this group. Further, some men with low serum-PSA remain unnoticed for CaP until they develop disease. Thus, there is a need to identify a reliable diagnostic and predictive biomarker of CaP. Here, we show that BMI1 stem-cell protein is secretory and could be explored for biomarker use in CaP patients.

METHODOLOGY/PRINCIPAL FINDINGS

Semi-quantitative analysis of BMI1 was performed in prostatic tissues of TRAMP (autochthonous transgenic mouse model), human CaP patients, and in cell-based models representing normal and different CaP phenotypes in African-American and Caucasian men, by employing immunohistochemistry, immunoblotting and Slot-blotting. Quantitative analysis of BMI1 and PSA were performed in blood and culture-media of siRNA-transfected and non-transfected cells by employing ELISA. BMI1 protein is (i) secreted by CaP cells, (ii) increased in the apical region of epithelial cells and stromal region in prostatic tumors, and (iii) detected in human blood. BMI1 is detectable in blood of CaP patients in an order of increasing tumor stage, exhibit a positive correlation with serum-PSA and importantly is detectable in patients which exhibit low serum-PSA. The clinical significance of BMI1 as a biomarker could be ascertained from observation that CaP cells secrete this protein in higher levels than cells representative of benign prostatic hyperplasia (BPH).

CONCLUSIONS/SIGNIFICANCE

BMI1 could be developed as a dual bio-marker (serum and biopsy) for the diagnosis and prognosis of CaP in Caucasian and African-American men. Though compelling these data warrant further investigation in a cohort of African-American patients.

Measurement of affective and activity pain interference using the Brief Pain Inventory (BPI): Cancer and Leukemia Group B 70903

OBJECTIVE

The Brief Pain Inventory (BPI) was designed to yield separate scores for pain intensity and interference. It has been proposed that the pain interference factor can be further broken down into unique factors of affective (e.g., mood) and activity (e.g., work) interference. The purpose of this analysis was to confirm this affective/activity interference dichotomy.

PATIENTS AND METHODS

A retrospective confirmatory factor analysis was completed for a sample of 184 individuals diagnosed with castrate-resistant prostate cancer (age 40-86, mean = 65.46, 77% White non-Hispanic) who had been administered the BPI as part of Cancer and Leukemia Group B trial 9480. A one-factor model was compared against two-factor and three-factor models that were developed based on the design of the instrument.

RESULTS

Root mean squared error of approximation (0.075), comparative fit index (0.971), and change in chi-square, given the corresponding change in degrees of freedom (13.33, P < 0.05) values for the three-factor model (i.e., pain intensity, activity interference, and affective interference), were statistically superior in comparison with the one- and two-factor models. This three-factor structure was found to be invariant across age, mean prostate-specific antigen, and hemoglobin levels.

CONCLUSIONS

These results confirm that the BPI can be used to quantify the degree to which pain separately interferes with affective and activity aspects of a patient's everyday life. These findings will provide clinical trialists, pharmaceutical sponsors, and regulators with confidence in the flexibility of the BPI as they consider the use of this instrument to assist with understanding the patient experience as it relates to treatment.

The effects of short-term genistein intervention on prostate biomarker expression in patients with localised prostate cancer before radical prostatectomy

Nutritionally relevant levels of genistein, the predominant isoflavone in soyabean associated with lower risk of prostate cancer (PCa), may modulate the expression of prostate tissue biomarkers associated with cancer prediction and progression. A phase 2 placebo-controlled, randomised, double-blind clinical trial was conducted in forty-seven Norwegian patients before prostatectomy. Intervention was 30 mg genistein or placebo capsules daily for 3-6 weeks. Luminal cells from malignant and benign glands were isolated with laser capture microdissection and the mRNA levels of androgen-related biomarkers (androgen receptor, NK3 homeobox 1, kallikrein-related peptide 4 (KLK4)) and cell cycle-related genes (p21 Waf1/Cip1 , p27 Kip1 , p53) were analysed with real-time semiquantitative PCR. Immunohistochemistry of androgen-, cell cycle-, proliferative- (Ki67 nuclear antigen), apoptotic- (B-cell CLL/lymphoma 2 (BCL-2) and BCL-2-associated X protein) and neuroendocrine differentiation-related biomarkers (neuron-specific enolase and cytoplasmic chromogranin A) was performed using tissue microarrays containing normal, Gleason grade 3 and grade 4 prostate tissues. There were no significant effects by genistein intervention on proliferation-, cell cycle-, apoptosis- or neuroendocrine biomarkers. Genistein intervention, however, significantly reduced the mRNA level of KLK4 in tumour cells (P = 0·033) and there was a non-significant reduction in androgen and cell cycle-related biomarkers, except for p27Kip1, whose expression in the nuclear compartment was increased. Genistein intervention modulated the expression of several biomarkers which may be related to PCa prediction and progression. The present study supports genistein as a chemopreventive agent in PCa. Further investigation is warranted in larger and longer-duration studies.

Neuroendocrine differentiation in castration-resistant prostate cancer: a systematic diagnostic attempt

BACKGROUND

Assessing the neuroendocrine (NE) pattern in castration-resistant prostate cancer (CRPC) may prove useful in selecting potential responders to target therapies such as somatostatin analogues. The aim of this study was to define a panel of markers or examinations appropriate to characterize NE differentiation (NED).

METHODS

Forty-seven patients with CRPC underwent a systematic diagnostic attempt to characterize the NE phenotype using a plasma blood test for chromogranin A (CgA) and immunohistochemical staining of needle biopsy-obtained specimens (CgA, somatostatin receptor 2 [SSTR2], Ki-67, and androgen receptors). In a subgroup of 26 patients, somatostatin receptor scintigraphy using (111)In-DTPA-d-Phe octreotide (octreotide scintigraphy; Octreoscan, Covidien, Hazelwood, MO) was also performed.

RESULTS

NED was found in 85.1% of patients (if serum CgA, tissular CgA, and tissular SSTR2 were considered separately: 54%, 67%, and 58%, respectively). Only 15% of the 26-patient subgroup had an abnormal octreotide scintigraphy result. Although p-CgA and t-CgA were associated with more aggressive disease with a worse prognosis, patients with positive tissular SSTR2 staining had longer overall survival (OS).

CONCLUSION

This systematic approach to explore the NED in a quite homogeneous group of patients with CRPC seems reproducible and appropriate. Further investigations are required to validate this panel and better characterize potential responders to targeted therapy.

Prognostic significance of neuroendocrine differentiation in prostate adenocarcinoma

Much progress has been made toward an understanding of the development and progression of prostate cancer (PC) and the factors that drive the development of androgen independence. Neuroendocrine (NE) cells may provide an intriguing link between NE cell differentiation (NED) and tumor progression in PC. NED in PC generally confers a more aggressive clinical behavior and less favorable prognosis than conventional PC. In this article, we review the known functions of NE cells in PC and discuss the current knowledge on stimulation of cancer proliferation, invasion, apoptosis resistance, serum and immunohistochemical markers, and the prognostic significance of NED in human PC.

Prognostic, predictive, and surrogate factors for individualizing treatment for men with castration-resistant prostate cancer

With the surge in therapeutic options for castration-resistant prostate cancer (CRPC) comes increasingly complicated treatment decision making, highlighting the need for biomarkers that can identify appropriate patients for specific treatments and accurately assess disease response. Here we discuss existing and potential prognostic, predictive, and surrogate biomarkers in CRPC.

Biomarkers in the management and treatment of men with metastatic castration-resistant prostate cancer

CONTEXT

We have recently witnessed a rapid increase in the number of effective systemic agents for men with metastatic castration-resistant prostate cancer (CRPC), including novel hormonal therapies (abiraterone acetate and MDV3100), immunotherapies (sipuleucel-T), chemotherapies (cabazitaxel), and bone microenvironment targeting agents (denosumab, radium 223). Given the increasing complexity of treatment decisions for this disease, major research and clinical priorities are (1) finding biomarkers that enable an understanding of the natural history and complex biology of this heterogeneous malignancy, (2) defining predictive biomarkers that identify men most likely to benefit from a given therapy, and (3) identifying biomarkers of early response or progression to optimize outcomes.

OBJECTIVE

In this review, we discuss existing and potential biomarkers in CRPC and how they may currently inform prognosis, aid in treatment selection (predictive value), and relate to survival outcomes (surrogacy).

EVIDENCE ACQUISITION

PubMed-based literature searches and abstracts through September 2011 provided the basis for this literature review as well as expert opinion.

EVIDENCE SYNTHESIS

We address blood and urine-based biomarkers such as prostate-specific antigen, lactate dehydrogenase, total and bone alkaline phosphatase and other bone turnover markers, hemoglobin, and circulating tumor cells in the context of prognosis, prediction, and patient selection for therapy. Given the inherent problems associated with defining progression-free survival in CRPC, the importance of biomarker development and the needed steps are highlighted. We place the discussion of biomarkers within the context of the design/intent of a trial and mechanism of action of a given systemic therapy. We discuss novel biomarker development and the pathway for surrogate or predictive biomarkers to become credentialed as useful tests that inform therapeutic decisions.

CONCLUSIONS

A greater understanding of biomarkers in CRPC permits a more personalized approach to care that maximizes benefit and minimizes harm and can inform clinical trials tailored to men most likely to derive benefit.

Gastrin-releasing peptide: predictor of castration-resistant prostate cancer?

BACKGROUND

Neuroendocrine (NE) cells of the prostate are known to be androgen-independent and NE peptides like gastrin-releasing peptide (GRP) or neuron-specific enolase (NSE) can stimulate growth in a paracrine manner, and this is thought to be one of the escape mechanisms in castration-resistant prostate cancer (CRPCa). In a longitudinal study, we investigated the development of the NE serum factors GRP, NSE, and chromogranin A and their correlation with prostate-specific androgen (PSA) during hormonal treatment.

MATERIALS AND METHODS

Thirty two patients, with histology-proven, localized or metastatic prostatic carcinoma (PCa), who were undergoing therapy with LHRH analogue or a combination of LHRH analog and peripheral androgen blockade, took part in the study. In addition, eight healthy volunteers were each tested twice for serum GRP to elicit a "physiological" standard value. Blood samples were taken periodically from each patient within an 18-month time frame.

RESULTS

We defined the standard value for GRP in the healthy participants as 0.852 ng/ml (mean  +  2 SD) and observed that the GRP values for patients with PCa were significantly higher (P = 0.034). There was a positive correlation between PSA and GRP in patients with biochemical failure. CgA correlated with PSA development in the CRPCa patients. NSE values rose steadily over the study period, but with no correlation to PSA.

CONCLUSION

Our data confirm that NE factors are elevated during hormonal treatment of prostate cancer. GRP is higher in PCa patients undergoing androgen deprivation therapy and is possibly involved in the initiation of hormonal escape in PCa.

Alternative Tests to Psa for Prostate Cancer Diagnosis

Prostate specific antigen (PSA) is still the most useful tool to select the population requiring prostate biopsy. The main downsides of PSA are an inadequate sensitivity to be used in screening and a low specificity for cancer detection.

So far, a limited value for PSA derivates (velocity, density, free, proisoforms and doubling time) has been recognised.

We present a short review of the literature describing a selection of the most promising alternatives to PSA being studied currently: PCA3, serum kallikreins, serum detectable prostate specific membrane antigen, the nuclear matrix protein EPCA, EPCA-2, prostatic acid phosphatase, urine detectable GSTP1, anti-AMACR antibodies, sarcosine, plasminogen activating urokinase, IGFBP, TGF beta 1, PSP94, IL6, plasmatic DNA, serum autoantibodies, neuroendocrine markers, proteomic analysis.

Prognostic role of neuroendocrine differentiation in prostate cancer, putting together the pieces of the puzzle

Neuroendocrine (NE) differentiation is a common feature in prostate cancer (PC). The clinical significance of this phenomenon is controversial; however preclinical and clinical data are in favor of an association with poor prognosis and early onset of a castrate resistant status. NE PC cells do not proliferate, but they can stimulate the proliferation of the exocrine component through the production of paracrine growth factors. The same paracrine signals may favor the outgrowth of castrate adapted tumors through androgen receptor dependent or independent mechanisms. Noteworthy, NE differentiation in PC is not a stable phenotype, being stimulated by several agents including androgen deprivation therapy, radiation therapy, and chemotherapy. The proportion of NE positive PC, therefore, is destined to increase during the natural history of the disease. This may complicate the assessment of the prognostic significance of this phenomenon. The majority of clinical studies have shown a significant correlation between NE differentiation and disease prognosis, confirming the preclinical rationale. In conclusion the NE phenotype is a prognostic parameter in PC. Whether this phenomenon is a pure prognostic factor or whether it can influence the prognosis by favoring the onset of a castrate resistance status is a matter of future research.

The prognostic role of immunohistochemical chromogranin a expression in prostate cancer patients is significantly modified by androgen-deprivation therapy

BACKGROUND

Several data suggest that neuroendocrine (NE) differentiation in prostate cancer is implicated in the development of resistance to androgen-deprivation therapy (ADT). This study was undertaken to assess the prognostic role of tissue chromogranin A (CgA) expression in patients addressed to ADT as opposed to those who did not.

METHODS

Four hundred fourteen newly diagnosed prostate cancer patients, consecutively recruited in a single institution, entered the study. Two hundred fourteen patients received ADT early after diagnosis, 200 did not. Median follow-up was 85 months. CgA expression was evaluated immunohistochemically in prostate cancer needle biopsies.

RESULTS

In multivariate analysis after adjusting for Gleason score, serum PSA, disease stage and local treatments, tissue CgA expression in overall cases was significantly associated with a shorter survival (P = 0.009) but failed to be associated with PSA progression (P = 0.10). Dividing patients according to whether they received immediate ADT or not, tissue CgA was associated with a shorter time to PSA progression in ADT-treated patients (hazard ratios (HR) 1.96, 95% confidence interval (CI): 1.37-2.81, P = 0.0001), but failed to be associated in those who did not (HR 0.87, 95% CI: 0.58-1.30, P = 0.49), interaction test P = 0.007. Conversely the survival effect of tissue CgA was not modified by ADT (interaction test, P = 0.41).

CONCLUSIONS

Tissue CgA expression, evaluated in prostate cancer needle biopsies at diagnosis, is an independent prognostic factor of survival in prostate cancer patients. The negative influence of NE differentiation on time to progression confined in ADT-treated patients suggests a role of NE differentiation in predicting endocrine resistance that deserves validation.

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

OBJECTIVES

To examine whether pretreatment serum human epidermal growth factor receptor 2 (HER2/neu) and immunohistochemical HER2/neu expression predict biochemical recurrence-free survival in advanced prostate cancer.

METHODS

We studied 75 untreated patients with metastatic prostate cancer and compared them to a control group of 97 patients without histologically diagnosed prostate cancer. Serum samples were collected for HER2/neu protein analysis before the patients started endocrine therapy. HER2/neu expression in the prostate tissue was evaluated using immunohistochemical analysis.

RESULTS

Serum concentration of HER2/neu in patients with prostate cancer was significantly higher than in those without cancer (P = 0.005). Based on the median HER2/neu value, a cut-off level of 12.5 ng/mL was established to separate low from high serum HER2/neu levels. The biochemical recurrence-free survival rate was significantly lower in patients with a high serum HER2 level (P < 0.001). HER2/neu overexpression was found in 18 patients (24%) by immunohistochemical analysis. Biochemical recurrence-free survival rates did not show a statistically significant difference between HER2/neu positive and negative groups. Multivariate analysis showed that the pretreatment serum HER2/neu value was an independent predictor of biochemical recurrence (P = 0.02).

CONCLUSIONS

Pretreatment serum HER2/neu may represent a more valuable tool than immunohistochemical HER2/neu expression for the prediction of biochemical recurrence in metastatic prostate cancer patients.

Cushing's syndrome due to ectopic ACTH production by (neuroendocrine) prostate carcinoma

Ectopic adrenocorticotropin (ACTH) secretion accounts for less than 10% of all causes of endogenous Cushing's syndrome (CS) and is usually associated with neuroendocrine tumors and small cell carcinoma of the lung. We report the case of a 62-year-old man with CS due to ectopic ACTH production by small cell carcinoma of the prostate. He presented with severe hypercortisolism and associated symptoms. Plasma neuron specific enolase (NSE) was grossly elevated. Despite performing a laparoscopic bilateral adrenalectomy, the patient died as a result of sepsis with multi-organ failure. Post-mortem immunohistochemical staining of prostate tumor tissue showed ACTH expression. ACTH staining was also performed in four additional patients with small cell carcinoma of the urinary tract without CS. None of these additional cases showed a positive staining for ACTH. Although a rare cause of ectopic ACTH production, neuroendocrine prostate carcinoma should be considered in male patients with Cushing's syndrome, in particular in those with an occult source of ACTH overproduction.

Correlation of three immunohistochemically detected markers of neuroendocrine differentiation with clinical predictors of disease progression in prostate cancer

BACKGROUND

The importance of immuno-histological detection of neuroendocrine differentiation in prostatic adenocarcinoma with respect to disease at presentation and Gleason grade is gaining acceptance. There is limited literature on the relative significance of three commonly used markers of NE differentiation i.e. Chromogranin A (CgA), Neuron specific enolase (NSE) and Synaptophysin (Syn). In the current work we have assessed the correlation of immuno-histological detection of neuroendocrine differentiation in prostatic adenocarcinoma with respect to disease at presentation and Gleason grade and to determine the relative value of various markers.

MATERIALS AND METHODS

Consecutive samples of malignant prostatic specimens (Transurethral resection of prostate or radical retropubic prostatectomy) from 84 patients between January 1991 and December 1998 were evaluated by immunohistochemical staining (PAP technique) using selected neuroendocrine tumor markers i.e. Chromogranin A (CgA), Neuron specific enolase (NSE), and Synaptophysin (Syn). According to the stage at diagnosis, patients were divided into three groups. Group (i) included patients who had organ confined disease, group (ii) included patients with locally invasive disease, and group (iii) with distant metastasis. NE expression was correlated with Gleason sum and clinical stage at presentation and analyzed using Chi-Square test and one way ANNOVA.

RESULTS

The mean age of the patients was 70 +/- 9.2 years. Group I had 14 patients, group II had 31 patients and group III had 39 patients. CgA was detected in 33 cases, Syn in 8 cases, and NSE in 44 cases. Expression of CgA was seen in 7% of group I, 37% in group II and 35% of group III patients (p 0.059). CgA (p 0.024) and NSE (p 0.006) had a significantly higher expression with worsening Gleason grade.

CONCLUSION

CgA has a better correlation with disease at presentation than other markers used. Both NSE and CgA had increasing expression with worsening histological grade this correlation has a potential for use as a prognostic indicator. Limitations in the current work included small number and retrospective nature of work. The findings of this work needs validation in a larger cohort.

Emerging Biomarkers for the Diagnosis and Prognosis of Prostate Cancer

Background: Early detection of prostate cancer (CaP), the most prevalent cancer and the second-leading cause of death in men, has proved difficult, and current detection methods are inadequate. Prostate-specific antigen (PSA) testing is a significant advance for early diagnosis of patients with CaP.

Content: PSA is produced almost exclusively in the prostate, and abnormalities of this organ are frequently associated with increased serum concentrations. Because of PSA’s lack of specificity for CaP, however, many patients undergo unnecessary biopsies or treatments for benign or latent tumors, respectively. Thus, a more specific method of CaP detection is required to augment or replace screening with PSA. The focus recently has been on creating cost-effective assays for circulating protein biomarkers in the blood, but because of the heterogeneity of CaP, it has become clear that this effort will be a formidable challenge. Each marker will require proper validation to ensure clinical utility. Although much work has been done on variations of the PSA test (i.e., velocity, density, free vs bound, proisoforms) with limited usefulness, there are many emerging markers at various stages of development that show some promise for CaP diagnosis. These markers include kallikrein-related peptidase 2 (KLK2), early prostate cancer antigen (EPCA), PCA3, hepsin, prostate stem cell antigen, and α-methylacyl-CoA racemase (AMACR). We review biomarkers under investigation for the early diagnosis and management of prostate cancer.

Summary: It is hoped that the use of panels of markers can improve CaP diagnosis and prognosis and help predict the therapeutic response in CaP patients.

Human ASH1 expression in prostate cancer with neuroendocrine differentiation

Neuroendocrine differentiation in prostate cancer correlates with overall prognosis and disease progression after androgen-deprivation therapy, although its specific mechanisms are currently poorly understood. A role of Notch pathway has been reported in determining neuroendocrine phenotype of normal and neoplastic tissues. The aim of this study was to analyze whether this pathway might affect neuroendocrine differentiation in prostate cancer. Human achaete-scute homolog 1 (hASH1), a pivotal member of the Notch pathway, was investigated in 80 prostate cancers selected and grouped according to chromogranin A immunohistochemistry, as follows: prostate cancers without neuroendocrine differentiation, untreated (25 cases); prostate cancers with neuroendocrine differentiation, untreated (40 cases); prostate cancers with previous androgen-deprivation therapy, all having neuroendocrine differentiation (15 cases). Human ASH1 protein was analyzed by immunohistochemistry, whereas the presence of hASH1 mRNA transcripts was investigated on paraffin material by real-time PCR. By immunohistochemistry, hASH1 was colocalized with chromogranin A in neuroendocrine cells of normal prostatic gland. It was absent in all but one prostate cancers without neuroendocrine differentiation, whereas it was positive in 25% of prostate cancers with neuroendocrine differentiation/untreated, with a significant correlation with the extent of neuroendocrine features (P=0.02). Moreover, comparing untreated and treated prostate cancers with neuroendocrine differentiation, a positive association with androgen-deprivation therapy was observed (P=0.01). In prostate cancers with neuroendocrine differentiation, RNA analysis confirmed the association of higher transcript levels in androgen deprivation-treated compared with untreated patients (P=0.01). In addition, hASH1 mRNA analysis in microdissected chromogranin A-positive and chromogranin A-negative areas within the same tumor demonstrated a two- to sevenfold increase of hASH1 mRNA expression in chromogranin A-positive tumor cell populations.

Blood biomarkers for prostate cancer detection and prognosis

Prostate cancer is the most non-cutaneous malignancy diagnosed in men in the USA. The discovery of prostate-specific antigen (PSA) revolutionized prostate cancer diagnosis and management in the 1990s. Despite its remarkable performance as a marker for prostate cancer, PSA is not prostate cancer specific. PSA can be released by normal as well as hyperplastic prostate cells, which undermines the specificity of PSA for prostate cancer diagnosis. Hence, there is a need for new biomarkers that can detect prostate cancer and, in addition, distinguish indolent from biologically aggressive cancers. Moreover, the emergence of new therapeutic approaches for prostate cancer cannot flourish without a more reliable set of markers to serve as prognosticators, targets and surrogate end points of disease progression and response to treatment. As the most useful clinical biomarkers are likely to be those assayed from blood, there is an increasing interest in profiling blood proteins. With recent advances in biotechnology such as high-throughput molecular analyses, many potential blood biomarkers have been identified and are currently under investigation.

Prognostic and Predictive Factors in Patients with Androgen-Independent Prostate Cancer Treated with Docetaxel and Estramustine: A Single Institution Experience

OBJECTIVES

To investigate potential prognostic and predictive factors in patients with androgen-independent prostate cancer (AIPC) treated with docetaxel chemotherapy.

METHODS

This analysis included 94 consecutive AIPC patients who were treated between March 2001 and May 2006 with biweekly docetaxel 45 mg/m(2) (day 2) and estramustine 140 mg three dimes daily (days 1-3).

RESULTS

Prostate-specific antigen (PSA) responses were observed in 45 of 84 evaluable patients (53%), whereas objective responses were observed in 16 of 40 patients with measurable disease (40%). Median survival (OS) was 16.2 mo (95% confidence interval [CI], 12.9-19.4) and median time to PSA progression (TTP) 5.0 mo (95%CI, 3.6-7.1). OS was independently associated with pain score baseline PSA and weight loss. Patients with only extraosseous disease had higher PSA response rate (87% vs. 49%, p=0.014) and superior TTP compared with patients with bone metastases with or without extraosseous disease (7.3 vs. 4.3 vs. 4 mo, p=0.002). Concurrent bone and extraosseous metastases were associated with worse prognosis compared with each site alone (median OS: 12.3 vs.19 vs.18.3 mo, p=0.007).

CONCLUSIONS

Among patients with AIPC treated with biweekly docetaxel and estramustine, baseline PSA >100, existence of pain, weight loss, and simultaneous extraosseous and bone disease were associated with worse prognosis. Extraosseous metastases seem to be more sensitive than bone disease to this chemotherapy.

A contemporary prognostic nomogram for men with hormone-refractory metastatic prostate cancer: a TAX327 study analysis

PURPOSE

To develop a prognostic model and nomogram using baseline clinical variables to predict death among men with metastatic hormone-refractory prostate cancer (HRPC).

EXPERIMENTAL DESIGN

TAX327 was a clinical trial that randomized 1,006 men with metastatic HRPC to receive every three week or weekly docetaxel or mitoxantrone, each with prednisone. We developed a multivariate Cox model and nomogram to predict survival at 1, 2, and 5 years.

RESULTS

Ten independent prognostic factors other than treatment group were identified in multivariate analysis: (a) presence of liver metastases [hazard ratio (HR), 1.66; P = 0.019], (b) number of metastatic sites (HR, 1.63 if > or =2 sites; P = 0.001), (c) clinically significant pain (HR, 1.48; P < 0.0001), (d) Karnofsky performance status (HR, 1.39 if < or =70; P = 0.016), (e) type of progression (HR, 1.37 for measurable disease progression and 1.29 for bone scan progression; P = 0.005 and 0.01, respectively), (f) pretreatment prostate-specific antigen (PSA) doubling time (HR, 1.19 if <55 days; P = 0.066), (g) PSA (HR, 1.17 per log rise; P < 0.0001), (h) tumor grade (HR, 1.18 for high grade; P = 0.069), (i) alkaline phosphatase (HR, 1.27 per log rise; P < 0.0001), and (j) hemoglobin (HR, 1.11 per unit decline; P = 0.004). A nomogram was developed based on this multivariate model and validated internally using bootstrap methods, with a concordance index of 0.69.

CONCLUSIONS

This multivariate model identified several new independent prognostic factors in men with metastatic HRPC, including PSA doubling time, and led to the successful development of a clinically applicable nomogram. External prospective validation may support the wider use of this prognostic baseline model for men with HRPC treated with chemotherapy.