PROSTATE SPECIFIC ANTIGEN ONLY PROGRESSION OF PROSTATE CANCER:

Integrated high-throughput analysis identifies super enhancers in metastatic castration-resistant prostate cancer

Background: Metastatic castration-resistant prostate cancer (mCRPC) is a highly aggressive stage of prostate cancer, and non-mutational epigenetic reprogramming plays a critical role in its progression. Super enhancers (SE), epigenetic elements, are involved in multiple tumor-promoting signaling pathways. However, the SE-mediated mechanism in mCRPC remains unclear. Methods: SE-associated genes and transcription factors were identified from a cell line (C4-2B) of mCRPC by the CUT&Tag assay. Differentially expressed genes (DEGs) between mCRPC and primary prostate cancer (PCa) samples in the GSE35988 dataset were identified. What's more, a recurrence risk prediction model was constructed based on the overlapping genes (termed SE-associated DEGs). To confirm the key SE-associated DEGs, BET inhibitor JQ1 was applied to cells to block SE-mediated transcription. Finally, single-cell analysis was performed to visualize cell subpopulations expressing the key SE-associated DEGs. Results: Nine human TFs, 867 SE-associated genes and 5417 DEGs were identified. 142 overlapping SE-associated DEGs showed excellent performance in recurrence prediction. Time-dependent receiver operating characteristic (ROC) curve analysis showed strong predictive power at 1 year (0.80), 3 years (0.85), and 5 years (0.88). The efficacy of his performance has also been validated in external datasets. In addition, FKBP5 activity was significantly inhibited by JQ1. Conclusion: We present a landscape of SE and their associated genes in mCPRC, and discuss the potential clinical implications of these findings in terms of their translation to the clinic.

Management of Biochemical Recurrence after Primary Curative Treatment for Prostate Cancer: A Review

How to manage patients with prostate cancer (PCa) with biochemical recurrence (BCR) following primary curative treatment is a controversial issue. Importantly, this prostate-specific antigen (PSA)-only recurrence is a surrogate neither of PCa-specific survival nor of overall survival. Physicians are therefore challenged with preventing or delaying the onset of clinical progression in those deemed at risk, while avoiding over-treating patients whose disease may never progress beyond PSA-only recurrence. Adjuvant therapy for radical prostatectomy (RP) or local radiotherapy (RT) has a role in certain at-risk patients, although it is not recommended in low-risk PCa owing to the significant side-effects associated with RT and androgen deprivation therapy (ADT). The recommendations for salvage therapy differ depending on whether BCR occurs after RP or primary RT, and in either case, definitive evidence regarding the best strategy is lacking. Options for treatment of BCR after RP are RT at least to the prostatic bed, complete or intermittent ADT, or observation; for BCR after RT, salvage RP, cryotherapy, complete or intermittent ADT, brachytherapy, high-intensity focused ultrasound (HIFU), or observation can be considered. Many patient- and cancer-specific factors need to be taken into account when deciding on the best strategy, and optimal management depends on the involvement of a multidisciplinary team, consultation with the patient themselves, and the adoption of an individualised approach. Improvements in imaging techniques may enable earlier detection of metastases, which will hopefully refine future management decisions.

Comparative analysis of multiparametric magnetic resonance and PET-CT in the management of local recurrence after radical prostatectomy for prostate cancer

PURPOSE

Our aim was to assess whether multiparametric magnetic resonance and PET-CT can have a role in detecting local recurrence in patients with biochemical recurrence after radical prostatectomy.

METHODS

We reviewed the recent international literature by carrying out a PUBMED search.

RESULTS

We critically reviewed 11 recent original studies about the use of PET-CT and 5 recent studies about the use of multiparametric magnetic resonance. PET-CT has not shown significant results in terms of detection rate for local recurrence in patients with low level of PSA. Multiparametric magnetic resonance showed encouraging results to detect local recurrence in patients with low PSA and with small diameter lesions.

CONCLUSIONS

Currently, most important urological societies do not consider multiparametric magnetic resonance and PET-CT in the follow-up of patients with suspected local recurrence after radical prostatectomy. We can assert that multiparametric magnetic resonance seems to have excellent results in detecting local recurrence in patients submitted to radical prostatectomy and PSA<1.5 ng/ml.

A pilot trial of CTLA-4 blockade with human anti-CTLA-4 in patients with hormone-refractory prostate cancer

PURPOSE

Blockade of the T-cell inhibitory receptor CTL-associated antigen-4 (CTLA-4) augments and prolongs T-cell responses and is a strategy to elicit antitumor immunity. The objectives of this pilot study were to establish the pharmacokinetic and safety profile for a single dose of 3 mg/kg of the anti-CTLA-4 antibody Ipilimumab (MDX-010, BMS-734016) and to assess if this therapy resulted in prostate-specific antigen (PSA) modulation and the development of polyclonal T-cell activation and/or clinical autoimmunity in patients with hormone-refractory prostate cancer treated with Ipilimumab.

EXPERIMENTAL DESIGN

Patients with metastatic hormone-refractory prostate cancer received a single 3 mg/kg i.v. dose of Ipilimumab. Serologic measures of autoimmunity were obtained, and T-cell activation was evaluated by flow cytometry. Pharmacokinetic sampling of plasma for MDX-CTLA-4, PSA measurement, and diagnostic imaging were also undertaken.

RESULTS

Fourteen patients were treated: 12 patients received a single dose of Ipilimumab, and 2 patients were re-treated with a second dose upon PSA progression. Two patients showed PSA declines of > or =50%. Treatment was well tolerated with clinical autoimmunity limited to one patient who developed grade 3 rash/pruritus requiring systemic corticosteroids. The mean +/- SD Ipilimumab terminal elimination half-life was 12.5 +/- 5.3 days.

CONCLUSIONS

A single dose of 3 mg/kg Ipilimumab, an anti-CTLA-4 antibody, given to patients with prostate cancer is safe and does not result in significant clinical autoimmunity. PSA-modulating effects observed warrant further investigation.

A phase II trial of imatinib mesylate in patients with biochemical relapse of prostate cancer after definitive local therapy

OBJECTIVE

To determine the biological effects of imatinib mesylate (STI-571, Gleevec; Novartis Pharmaceuticals, Inc., East Hanover, NJ, USA), as measured by prostate-specific antigen (PSA) kinetics in men with biochemical relapse of prostate cancer after definitive local therapy.

PATIENTS AND METHODS

Men with prostate cancer, who had had definitive local therapy, with nonmetastatic recurrent disease as manifested by a rising PSA level, were enrolled on this phase II trial. Men received 400 mg of imatinib mesylate orally twice daily and continuously until disease progression or unacceptable toxicity. The PSA level was measured monthly.

RESULTS

In all, 20 men with biochemically relapsed prostate cancer were treated. The median pretreatment PSA level was 5.4 ng/mL. Of the 19 evaluable men, one achieved a >or= 50% reduction in PSA level and two had decreases of <50%. For the 16 men in whom the on-treatment PSA doubling time (PSADT) could be calculated (those with increasing PSA level) the median PSADT did not increase significantly (5.8 vs 7.2 months, P = 0.64). Eleven of 20 men discontinued therapy due to toxicity and the trial was stopped early due to toxicity.

CONCLUSIONS

Based on the lack of PSA modulation and pronounced toxicities leading to early closure of this trial, further study of single-agent imatinib mesylate at this dose (400 mg twice daily) cannot be recommended in this patient population.

Variables which might predict the response to salvage radiotherapy in chinese patients with biochemical failure after radical prostatectomy

BACKGROUND/AIMS

To evaluate the relationship between the variables and the outcomes of salvage radiotherapy (sRT) to find some predictors of sRT.

METHODS

The medical records of 56 patients receiving sRT for biochemical failure after radical prostatectomy (RP) were available for retrospective review. sRT was defined as external beam radiotherapy for patients with a continuous increase in the prostate-specific antigen (PSA) level of >or=0.2 ng/ml after RP. Response was defined as achievement of a PSA nadir of <or=0.1 ng/ml.

RESULTS

The mean follow-up period after sRT was 31.6 months. The predictors of response to sRT were PSA doubling time (PSADT) and seminal vesicle invasion. The median PSADT in responders was 6.5 months versus 4.0 months in non-responders (OR=1.66, p=0.006). The patients with a PSADT of >6 months were all responders. The response rate in patients with seminal vesicle invasion was 42.9% (6/14) versus 76.2% (32/42) in patients without seminal vesicle invasion (OR=0.119, p=0.015).

CONCLUSION

PSADT and the state of seminal vesicle invasion were good predictors of response to sRT. sRT was especially effective when the PSADT was >6 months and in patients without seminal vesicle invasion.

Cancer biomarkers: knowing the present and predicting the future

In recent years the discovery of cancer biomarkers has become a major focus of cancer research. The widespread use of prostate-specific antigen in prostate cancer screening has motivated researchers to identify suitable markers for screening different types of cancer. Biomarkers are also useful for diagnosis, monitoring disease progression, predicting disease recurrence and therapeutic treatment efficacy. With the advent of new and improved genomic and proteomic technologies such as DNA and tissue microarray, two-dimensional gel eletrophoresis, mass spectrometry and protein assays coupled with advanced bioinformatic tools, it is possible to develop biomarkers that are able to reliably and accurately predict outcomes during cancer management and treatment. In years to come, a serum or urine test for every phase of cancer may drive clinical decision making, supplementing or replacing currently existing invasive techniques.

Clinical trials in patients with biochemically relapsed prostate cancer

In this section there is a wide diversity of mini-reviews, covering several areas of interest for readers. Authors from the USA write about clinical trials in patients with biochemically relapsed prostate cancer, again bridging the divide between medical oncologists and urologists who specialise in urological oncological surgery. The second paper is a joint one from Germany and the USA, bringing the reader up to date with advances in the treatment of stress urinary incontinence. Finally there are two papers from Australia describing the use of positron emission tomography in renal cancer and in prostate cancer.

11C-Choline Positron Emission Tomography in Prostate Cancer: Primary Staging and Recurrent Site Staging

OBJECTIVES

To evaluate the usefulness of 11C-choline positron emission tomography (PET) for primary staging and re-staging of prostate cancer.

PATIENTS AND METHODS

11C-choline PET, a total of 22 scans, was performed on 13 patients with histologically proven prostate cancer in primary staging (n = 6) and recurrent site staging; following radical prostatectomy (n = 5) and following radiation therapy (n = 3). In 1 patient, 11C-choline PET was performed in both primary staging and re-staging. Also, 3 patients histologically proven to have no malignant prostate were included.

RESULTS

Because urinary 11C-choline activity was low, it did not interfere with the visualization of pelvic structures. 11C-choline PET visualized normal prostate with a mean SUV of 2.99 (range 2.27-3.68) and primary prostate cancer as a hot spot in 5/6 scans with a mean SUV of 4.21 (range 2.99-6.2). In re-staging, 11C-choline PET was true positive in 9/16 scans and true negative in 2/16 scans. 5/16 scans in 2 patients were false negative with negative conventional imaging.

CONCLUSIONS

In primary staging, 11C-choline PET may not be of use because of no reliable differential 11C-choline uptake of BPH and prostate cancer. On the other hand, 11C-choline PET may be of value in recurrent site staging and monitoring for the prostate cancer.

Diagnosis of local recurrence after radical prostatectomy

In the long-term there is biochemical evidence of recurrent prostate carcinoma in approximately 40% of patients after radical prostatectomy (RP). Detecting the site of recurrence (local vs distant) is critical for defining the optimum treatment. Pathological and clinical variables, e.g. Gleason score, involvement of seminal vesicles or lymph nodes, margin status at surgery, and especially the timing and pattern of prostate-specific antigen (PSA) recurrence, may help to predict the site of relapse. Transrectal ultrasonography (TRUS) of the prostatic fossa in association with TRUS-guided needle biopsy is considered more sensitive than a digital rectal examination for detecting local recurrence, especially if PSA levels are low. Although it cannot detect minimal tumour mass at very low PSA levels (< 1 ng/mL) TRUS biopsy is presently the most sensitive method for detecting local recurrence. Nevertheless, the conclusive role of biopsy of the vesico-urethral anastomosis remains unclear. However, 111In-capromab pendetide scintigraphy and [11C]-choline tomography (which are better than conventional imaging for detecting metastatic tumour), have low detection rates for local disease and are considered complementary to TRUS in this setting. Patients with a high PSA after RP may be managed with external beam salvage radiotherapy. An initial PSA of < 1 ng/mL, Gleason score < 8 and radiation dose of 66-70 Gy seem to be key factors in determining success. Although a positive TRUS anastomotic biopsy may predict a better outcome after radiation therapy, the need to take a biopsy in the event of PSA failure remains under investigation. The value of salvage radiation to the prostatic bed for PSA-only progression after RP remains in question.

The androgen receptor: a potential target for therapy of prostate cancer

The androgen receptor plays a pivotal role in the prostate. Its primary function is to provide responsive gene products for differentiation and growth, but under abnormal conditions it contributes to the development of prostate cancer. The goal of this review is to elucidate the molecular functions of the androgen receptor and its role in prostate cancer. Initially the function of the androgen receptor will be described. Next, the clinical diagnosis, epidemiological impact, and treatments of androgen-dependent and -independent prostate cancer will be discussed. Finally we will examine how the mechanism of androgen action has played a role in the translation of new therapies and how this may influence future treatment modalities of prostate cancer.