Association between the dihydrotestosterone level in the prostate and prostate cancer aggressiveness using the Gleason score

Intraprostatic hormone dosage: Validation of a novel prostate biopsy technique

BACKGROUND

Advances in chromatography and mass spectrometry have allowed us to develop a novel technique for measuring intraprostatic hormone concentrations directly on prostate needle biopsies, rather than using traditional punch excision. This has significant clinical implications as intraprostatic dihydrotestosterone and testosterone levels could help monitor prostate growth, neoplasia and castration resistance.

METHODS

Patients undergoing radical cystoprostatectomy for bladder cancer were prospectively included. Each prostate specimen received one 90mg punch excision and six needle biopsies. Intraprostatic hormones were dosed through gas chromatography-mass spectrometry.

RESULTS

We included twenty patients, of which eleven were incidentally diagnosed with prostate cancer; four had ISUP 1 (20%) and seven had ISUP 2 (35%). The prostate biopsy technique was unable to obtain measures for testosterone, Delta-4-androsterone and androstenedione. Tissue concentrations of DHEA, DHT, E1 and E2 can be obtained with no significant difference from the reference established on a punch from a single biopsy core sample.

CONCLUSIONS

Our study demonstrates that intraprostatic concentrations of DHEA, DHT, E1 and E2 can be measured without significant difference from the reference established on a single punch excision. This finding opens the way to research on the interactions between endocrinology and prostate oncogenesis and particularly on the mechanisms of resistance to hormone therapies in vivo.

LEVEL OF EVIDENCE: 2

Advances in the Current Understanding of the Mechanisms Governing the Acquisition of Castration-Resistant Prostate Cancer

Despite aggressive treatment and androgen-deprivation therapy, most prostate cancer patients ultimately develop castration-resistant prostate cancer (CRPC), which is associated with high mortality rates. However, the mechanisms governing the development of CRPC are poorly understood, and androgen receptor (AR) signaling has been shown to be important in CRPC through AR gene mutations, gene overexpression, co-regulatory factors, AR shear variants, and androgen resynthesis. A growing number of non-AR pathways have also been shown to influence the CRPC progression, including the Wnt and Hh pathways. Moreover, non-coding RNAs have been identified as important regulators of the CRPC pathogenesis. The present review provides an overview of the relevant literature pertaining to the mechanisms governing the molecular acquisition of castration resistance in prostate cancer, providing a foundation for future, targeted therapeutic efforts.

Determination of Intraprostatic and Intratesticular Androgens

Androgens represent the main hormones responsible for maintaining hormonal balance and function in the prostate and testis. As they are involved in prostate and testicular carcinogenesis, more detailed information of their active concentration at the site of action is required. Since the introduction of the term intracrinology as the local formation of active steroid hormones from inactive precursors of the adrenal gland, mainly dehydroepiandrosterone (DHEA) and DHEA-S, it is evident that blood circulating levels of sex steroid hormones need not reflect their actual concentrations in the tissue. Here, we review and critically evaluate available methods for the analysis of human intraprostatic and intratesticular steroid concentrations. Since analytical approaches have much in common in both tissues, we discuss them together. Preanalytical steps, including various techniques for separation of the analytes, are compared, followed by the end-point measurement. Advantages and disadvantages of chromatography-mass spectrometry (LC-MS, GC-MS), immunoanalytical methods (IA), and hybrid (LC-IA) are discussed. Finally, the clinical information value of the determined steroid hormones is evaluated concerning differentiating between patients with cancer or benign hyperplasia and between patients with different degrees of infertility. Adrenal-derived 11-oxygenated androgens are mentioned as perspective prognostic markers for these purposes.

Association of prostate cancer SLCO gene expression with Gleason grade and alterations following androgen deprivation therapy

Background.

SLCO-encoded transporters have been associated with progression to castration resistant prostate cancer (CRPC) after initiation of androgen deprivation therapy (ADT). Although expressed at lower levels than in CRPC tissues, SLCO-encoded transporters may also play a role in response of primary prostate cancer (PCa) to ADT and biochemical recurrence.

Methods.

We systematically explored expression of the 11 human SLCO genes in a large sample of untreated and ADT-treated normal prostate (NP) and primary PCa tissues, including tumors treated with neoadjuvant abiraterone.

Results.

Transporters with the most recognized role in steroid uptake in PCa, including SLCO2B1 (DHEAS) and 1B3 (testosterone), were consistently detected in primary PCa. SLCO1B3 was nearly 5-fold higher in PCa vs NP with no difference in Gleason 3 vs 4 and no change with ADT. SLCO2B1 was detected at 3-fold lower levels in PCa than NP but was nearly 7-fold higher in Gleason 4 vs Gleason 3 and increased 3-fold following ADT (p<0.05 for all).

Conclusions.

We observed clear differences in SLCO expression in PCa vs NP samples, in Gleason 4 vs Gleason 3 tumors, and in ADT-treated vs untreated tissues. These findings are hypothesis generating due to small sample size, but suggest that baseline and ADT-induced changes in PCa OATP expression may influence steroid uptake and response to ADT, as well as uptake and response to drugs such as abiraterone and docetaxel which are also subject to OATP-mediated transport and are now being routinely combined with ADT in the metastatic castration sensitive setting.

Pre- and post-radical prostatectomy testosterone levels in prostate cancer patients

Radical prostatectomy is one of the treatment of choices for localized prostate cancer. Published data show that radical prostatectomy is associated with both an increase and decrease in testosterone levels. This study aimed to document the changes in pre- and postoperative serum testosterone levels after radical prostatectomy along with the associations between serum testosterone levels and prostate cancer profiles in Thai population. Localized and locally advanced prostate cancer patients who elected to have radical prostatectomy without prior androgen deprivation therapy were included in the study. Patients' demographic data, pre- and postoperative serum testosterone levels, sex hormone binding globulin, albumin, prostate-specific antigen, and final pathologic reports were collected. Eighty-five prostate cancer patients were included in this study. Mean age was 67.32 years. Mean pre- and postoperative serum testosterone levels were 424.95 ng/dL and 371.94 ng/dL, respectively (p-value < 0.001). There was a greater testosterone reduction in patients with a final pathologic report of Gleason 4 + 3 and above compared with those with a Gleason 3 + 3 and 3 + 4 (p-value = 0.001). No significant association between preoperative testosterone levels and final Gleason scores was observed. This study documented significant postoperative testosterone reductions in prostate cancer patients after a radical prostatectomy. Patients with high Gleason grades had greater testosterone reductions. These findings may have clinical implications for the prediction of postoperative hypogonadal states in prostate cancer patients.

Methodological approach to the intracrine study and estimation of DHEA and DHEA-S using liquid chromatography-tandem mass spectrometry (LC-MS/MS)

A reliable and sensitive method for analyzing steroids using liquid chromatography tandem mass spectrometry (LC-MS/MS) is required for research concerning dehydroepiandrosterone (DHEA), which plays a central role in steroid hormone biosynthesis and metabolism. Furthermore, after the first proposal of the concept of intracrine DHEA, stable isotope tracer analysis, which is useful for structural recognition as well as determination of steroids, has been required to evaluate physiological action and hormone biosynthesis/metabolism in target organs. We describe sample processing and analysis methods for simultaneous quantification of multiple hormones, including DHEA, in serum, saliva and tissue using LC-MS/MS. A derivatization technique compatible with each functional group for measuring 3β-hydroxy-5-enes, such as DHEA and 5α/5β-steroids, with high sensitivity and specificity is also described. Finally, we describe a newly developed method for intracrine research using stable isotope-labeled (13)C-steroid substrates with tracer analysis of their metabolites by LC-MS/MS.This article is part of a Special Issue entitled'Essential role of DHEA'.

Limited in vitro efficacy of CYP17A1 inhibition on human castration resistant prostate cancer

Although accumulating evidence indicates high expression of CYP17A1(P45017A1) allows castration resistant prostate cancer (CRPC) to maintain high intratumoral androgen levels, the potential P45017A1 activity has not been characterized yet. The aim of this study was to examine the potential CYP17A1 activity including 17α-hydroxylase and 17,20-lyase activities in human CRPC and the effect of a CYP17A inhibitor. We used three human CRPC cell lines: C4-2 and C4-2AT6 which was established from C4-2 under androgen ablation conditions for 6months, and PC3. To ascertain the potential CYP17A1 activity, we cultured with the steroid precursors: (13)C-[2,3,4]-progesterone (13C-Prog), and analyzed the sequential biosynthesis (13)C-[2,3,4]-17-hydroxyprogesterone (13C-17OHP) and (13)C-[2,3,4]-androstenedione(13C-Adione) by liquid chromatography/mass spectrometry (LC/MS/MS).The C4-2AT6 cells showed significantly higher CYP17A1 expression than C4-2 cells (p<0.001). LC/MS/MS analysis enabled us to detect the 13C-17-OHP and 13C-A-dione in these cell lines. The concentration ratio of 13C-Adione/13C-17OHP (Adione-17OHP ratio), which is thought to reflect the differences between 17-hydroxylase and 17,20-lyase activities, was then determined. The Adione-17OHP ratio in C4-2AT6 cells was significantly higher than that of C4-2 cells (p<0.001). Abiraterone were able to inhibit the CYP17A activities, although abiraterone did not have anti-proliferative effects on C4-2 and C4-2AT6 cells at clinically achievable concentrations of <1000nM in vitro. The present study clearly demonstrates CRPC have the dual activities of CYP17A1 mediated by 17-hydroxylase activity and 17,20-lyase activity. Abiraterone doesn't have an in vitro anti-proliferative efficacy in CRPC cells, suggesting limited efficacy in vitro.

High testosterone levels in prostate tissue obtained by needle biopsy correlate with poor-prognosis factors in prostate cancer patients

Background

There is currently no consensus on the correlations between androgen concentrations in prostate tissue and blood and stage and pathological grade of prostate cancer. In this study, we used a newly-developed ultra-sensitive liquid-chromatography tandem mass spectrometry method to measure testosterone (T) and dihydrotestosterone (DHT) concentrations in blood and needle biopsy prostate specimens from patients with prostate cancer.

Methods

We analyzed androgen levels in 196 men diagnosed with prostate cancer. All patients had undergone systematic needle biopsy, and an additional needle biopsy from the peripheral zone was conducted for the simultaneous determination of T and DHT. We analyzed the relationships between T and DHT levels in tissue and blood and Gleason score, clinical stage, and percentage of positive biopsy cores, using multivariate analysis.

Results

The median T and DHT levels in blood were 3551.0 pg/mL and 330.5 pg/mL, respectively. There was a strong correlation between serum T and DHT. The median T and DHT levels in prostate tissue were 0.5667 pg/mg and 7.0625 pg/mg, respectively. In multivariate analysis, serum prostate-specific antigen and tissue T levels were significantly associated with poor prognosis; high T levels in prostate tissue were significantly related to high Gleason score (p = 0.041), advanced clinical stage (p = 0.002), and a high percentage of positive biopsy cores (p = 0.001).

Conclusions

The results of this study indicate that high T levels in prostate tissue are related to high Gleason score, advanced clinical stage, and a high percentage of positive biopsy cores in patients with prostate cancer. T level in needle biopsy specimens may therefore be a useful prognostic factor in prostate cancer patients.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-717) contains supplementary material, which is available to authorized users.

Is DHT Production by 5α-Reductase Friend or Foe in Prostate Cancer?

The first advance in the history of studies on prostate cancer (PCa) and androgens was the development of treatment with castration and administration of estrogen by Charles B. Huggins, who won the Nobel Prize in Physiology and Medicine. Since then, and for 70 years, androgen deprivation therapy has been the standard therapy for advanced PCa and the center of studies on PCa. However, recent advances have shed light on the relationship between androgens and the development or the progression of PCa. The use of 5AR inhibitors to prevent progression of PCa continues to be widely discussed. Discussion has been fueled by the findings of two large randomized, placebo-controlled trials: the Prostate Cancer Prevention Trial with finasteride and the Reduction by Dutasteride of Prostate Cancer Events trial. Does the development of PCa or progression to castration-resistant PCa depend on dihydrotestosterone (DHT)? Here, we summarize and discuss recent topics of local androgen production of DHT in PCa.

GnRH agonists and the rapidly increasing use of combined androgen blockade in prostate cancer

The discovery of medical castration with GnRH agonists in 1979 rapidly replaced surgical castration and high doses of estrogens for the treatment of prostate cancer. Soon afterwards, it was discovered that androgens were made locally in the prostate from the inactive precursor DHEA of adrenal origin, a mechanism called intracrinology. Taking into account these novel facts, combined androgen blockade (CAB) using a pure antiandrogen combined with castration in order to block the two sources of androgens was first published in 1982. CAB was the first treatment shown in randomized and placebo-controlled trials to prolong life in prostate cancer, even at the metastatic stage. Most importantly, the results recently obtained with the novel pure antiandrogen enzalutamide as well as with abiraterone, an inhibitor of 17α-hydroxylase in castration-resistant prostate cancer, has revitalized the CAB concept. The effects of CAB observed on survival of heavily pretreated patients further demonstrates the importance of the androgens made locally in the prostate and are a strong motivation to apply CAB to efficiently block all sources of androgens earlier at start of treatment and, even better, before metastasis occurs. The future of research in this field thus seems to be centered on the development of more potent blockers of androgens formation and action in order to obtain better results at the metastatic stage and, for the localized stage, reduce the duration of treatment required to achieve complete apoptosis and control of prostate cancer proliferation before it reaches the metastatic or noncurable stage.

A hormone-dependent feedback-loop controls androgen receptor levels by limiting MID1, a novel translation enhancer and promoter of oncogenic signaling

BACKGROUND

High androgen receptor (AR) level in primary tumour predicts increased prostate cancer (PCa)-specific mortality. Furthermore, activations of the AR, PI3K, mTOR, NFκB and Hedgehog (Hh) signaling pathways are involved in the fatal development of castration-resistant prostate cancer during androgen ablation therapy. MID1, a negative regulator of the tumor-suppressor PP2A, is known to promote PI3K, mTOR, NFκB and Hh signaling. Here we investigate the interaction of MID1 and AR.

METHODS

AR and MID1 mRNA and protein levels were measured by qPCR, Western blot and immunohistochemistry. Co-immunoprecipitation followed by PCR and RNA-pull-down followed by Western blot was used to investigate protein-mRNA interaction, chromatin-immunoprecipitation followed by next-generation sequencing for identification of AR chromatin binding sites. AR transcriptional activity and activity of promoter binding sites for AR were analyzed by reporter gene assays. For knockdown or overexpression of proteins of interest prostate cancer cells were transfected with siRNA or expression plasmids, respectively.

RESULTS

The microtubule-associated MID1 protein complex associates with AR mRNA via purine-rich trinucleotide repeats, expansions of which are known to correlate with ataxia and cancer. The level of MID1 directly correlates with the AR protein level in PCa cells. Overexpression of MID1 results in a several fold increase in AR protein and activity without major changes in mRNA-levels, whereas siRNA-triggered knockdown of MID1 mRNA reduces AR-protein levels significantly. Upregulation of AR protein by MID1 occurs via increased translation as no major changes in AR protein stability could be observed. AR on the other hand, regulates MID1 via several functional AR binding sites in the MID1 gene, and, in the presence of androgens, exerts a negative feedback loop on MID1 transcription. Thus, androgen withdrawal increases MID1 and concomitantly AR-protein levels. In line with this, MID1 is significantly over-expressed in PCa in a stage-dependent manner.

CONCLUSION

Promotion of AR, in addition to enhancement of the Akt-, NFκB-, and Hh-pathways by sustained MID1-upregulation during androgen deprivation therapy provides a powerful proliferative scenario for PCa progression into castration resistance. Thus MID1 represents a novel, multi-faceted player in PCa and a promising target to treat castration resistant prostate cancer.

Corpulence is the crucial factor: association of testosterone and/or obesity with prostate cancer stage

OBJECTIVES

To evaluate whether low testosterone levels or obesity, or both, are directly associated with tumor stage/grade in patients with clinically localized prostate cancer.

METHODS

Preoperative androgen serum levels (total and free testosterone), sex hormone-binding globulin, body mass index and waist circumference were assessed in 510 consecutive European Caucasian men treated with radical prostatectomy. Hormone levels and body mass index/waist circumference were correlated with patient- and tumor-specific characteristics using multivariable logistic regression analysis.

RESULTS

Even though we confirmed an inverse correlation between bodyweight and testosterone levels, only overweight - but not low testosterone - was associated with advanced disease and poor differentiation of prostate cancer. Using multivariate analyses, both body mass index ≥30 kg/m(2) and waist circumference >110 cm were associated with high-grade disease (Gleason score ≥8). A waist circumference >110 cm also correlated significantly with lymph node metastasis.

CONCLUSIONS

This is the first study showing that obesity, but not low serum testosterone levels, is significantly associated with high grade and metastatic disease in men diagnosed with clinically localized prostate cancer. The present findings suggest that low androgen levels at diagnosis, which used to be held responsible for the development of aggressive prostate cancer, is only an epiphenomenon of obesity rather than the cause of prostate cancer development and/or progression.

Human castration resistant prostate cancer rather prefer to decreased 5α-reductase activity

Physiologically relevant steroid 5α-reductase (SRD5A) activity that is essential for dihydrotestosterone (DHT) biosynthesis in human castration-resistant prostate cancer (CRPC) has not been fully characterized yet. In this study to ascertain the potential SRD5A activity, we cultured two human CRPC cell lines, C4-2 and C4-2AT6, with the steroid precursor: ¹³C-[2,3,4]-androstenedione (13C-Adione), and analyzed the sequential biosynthesis of ¹³C-[2,3,4]-testosterone (13C-T) and ¹³C-[2,3,4]-DHT (13C-DHT) by liquid chromatography/mass spectrometry (LC/MS/MS). The 13C-DHT/13C-T concentration ratio detected by LC/MS/MS in C4-2AT6 cells appeared to reflect the SRD5A activity. The ratio in C4-2AT6 was significantly lower than that in C4-2. An increased concentration of DHT did not have a positive effect on cell proliferation, rather it exhibited inhibitory effects. 5α-reductase inhibitors did not have any inhibitory effect at clinically achievable concentrations. These results indicate that CRPC cells may have an unknown regulation system to protect themselves from an androgenic suppressive effect mediated by SRD5A activity.

Serum testosterone levels after medical or surgical androgen deprivation: a comprehensive review of the literature

Androgens and the androgen receptor play a role in the progression of prostate cancer. Androgen deprivation therapy (ADT) is a mainstay in the treatment of metastatic prostate cancer. ADT is expected to reduce serum testosterone levels from a normal level of about 500 to 600 ng/dl (17.3-20.8 nmol) down to castration levels. Traditionally, castration was considered to be achieved if testosterone levels were lowered to a threshold of 50 ng/dl (1.73 nmol/l), a definition determined more by measurement methods derived from the use of old assay methods than by evidence. Serum testosterone levels in three-quarter patients after surgical castration drop to less than 20 ng/dl (0.69 nmol/l). Ineffective suppression of testosterone is currently poorly recognized and may possibly have an effect of prostate cancer mortality. Persistent levels of serum testosterone after castration are mainly derived from adrenal androgens. Furthermore, the arrival of new therapies targeting androgen synthesis and androgen receptor activity has renewed interest on serum testosterone. This review discusses the biosynthetic pathway for androgen synthesis in humans and provides a comprehensive review of serum testosterone levels after surgical or medical castration. This review assesses serum testosterone levels after surgical castration and different pharmacologic castration in patients with prostate cancer under ADT, and ineffective testosterone suppression. The author proposes methods to better lower serum testosterone levels during ADT.

Diabetes predicts metastasis after radical prostatectomy in obese men: results from the SEARCH database

OBJECTIVE

To examine the association between diabetes and metastasis risk after radical prostatectomy (RP) and to determine if race or obesity modifies this relationship.

PATIENTS AND METHODS

Patients comprised 2058 US veterans with prostate cancer (PCa) enrolled in the Shared Equal-Access Regional Cancer Hospital (SEARCH) database and treated with RP between 1988 and 2010. The association of diabetes with metastasis risk or secondary treatment rates was examined using Cox proportional hazards, adjusting for preoperative and, separately, clinical and postoperative findings. The effect modification by race (black vs white) and obesity (body mass index [BMI] ≥30 vs <30 kg/m(2) ) was tested via interaction terms.

RESULTS

Men with diabetes had higher BMIs and were more likely to be non-white (all P ≤ 0.001). On multivariable analysis, diabetes was not associated with metastasis risk (P ≥ 0.45), but, among men with diabetes, longer diabetes duration was associated with higher metastasis risk (P ≤ 0.035). When stratified by obesity, diabetes was linked with higher metastasis risk in obese but not in non-obese men (P-interaction ≤ 0.037), but there was no significant interaction with race (P-interaction ≥ 0.56). Diabetes also predicted more aggressive secondary treatment among obese men but less aggressive treatment among non-obese men (hazard ratio 1.39 vs 0.63, P-interaction = 0.006). Where applicable, results were similar for both pre- and postoperative models.

CONCLUSIONS

Diabetes was not associated with metastasis risk overall. Stratification by obesity yielded significant differences, with diabetes linked to a fourfold higher metastasis risk in obese men, despite predicting more aggressive secondary treatment. Longer diabetes duration was also associated with increased metastasis risk.

Androgen deprivation therapy in combination with radiotherapy for high-risk clinically localized prostate cancer

Androgen deprivation therapy (ADT) has remained the main therapeutic option for patients with advanced prostate cancer (PCa) for about 70 years. Several reports and our findings revealed that aggressive PCa can occur under a low dihydrotestosterone (DHT) level environment where the PCa of a low malignancy with high DHT dependency cannot easily occur. Low DHT levels in the prostate with aggressive PCa are probably sufficient to propagate the growth of the tumor, and the prostate with aggressive PCa can produce androgens from the adrenal precursors more autonomously than that with non-aggressive PCa does under the low testosterone environment with testicular suppression. In patients treated with ADT the pituitary-adrenal axis mediated by adrenocorticotropic hormone has a central role in the regulation of androgen synthesis. Several experimental studies have confirmed the potential benefits from the combination of ADT with radiotherapy (RT). A combination of external RT with short-term ADT is recommended based on the results of phase III randomized trials. In contrast, the combination of RT plus 6 months of ADT provides inferior survival as compared with RT plus 3 years of ADT in the treatment of locally advanced PCa. Notably, randomized trials included patients with diverse risk groups treated with older RT modalities, a variety of ADT scheduling and duration and, importantly, suboptimal RT doses. The use of ADT with higher doses of RT or newer RT modalities has to be properly assessed.

Intraprostatic testosterone and dihydrotestosterone. Part I: concentrations and methods of determination in men with benign prostatic hyperplasia and prostate cancer

Owing to inconsistencies and methodological differences, the present peer-reviewed literature lacks conclusive data on the intraprostatic levels of androgens, in particular dihydrotestosterone (DHT), in untreated benign prostatic hyperplasia (BPH) and prostate cancer. To date, no difference has been shown between DHT concentrations in normal prostatic tissue and BPH, and nor has a difference been shown in DHT concentrations between the histologically distinct regions of the prostate. Recent literature has also failed to show a consistent difference in androgen level between BPH and prostate cancer. The role of intraprostatic DHT in the pathogenesis of BPH and in the initiation and progression of prostate cancer thus remains to be established. Increased knowledge of the mechanisms of the androgenic steroid pathways in prostatic diseases, with a special focus on intraprostatic androgen levels may lead to more optimized and more personalized forms of treatment, and probably new therapeutic targets as well.

Testosterone augments polyphenol-induced DNA damage response in prostate cancer cell line, LNCaP

Recently, we reported that combined ingestion of soy isoflavones and curcumin significantly decreased the serum level of prostate-specific antigen based on a randomized placebo-controlled double-blind clinical study. We investigated whether these polyphenols inhibited the proliferation of prostate cancer cells by activating a DNA damage response. The effects of isoflavones and curcumin on the expression and phosphorylation of ataxia-telangiectasia-mutated kinase (ATM), histone H2AX variant (H2AX) and checkpoint kinase2 (Chk2) were examined in LNCaP cells. The induction of apoptosis in LNCaP cells was evaluated by poly(ADP-ribose) polymerase (PARP) cleavage. Furthermore, the effects of a testosterone supplement on modulation of the DNA damage response were examined. Combined treatment of isoflavones and curcumin additively suppressed cellular proliferation and induced phosphorylation of ATM, histone H2AX, Chk2 and p53. Testosterone augmented the activation of the DNA damage response and PARP cleavage induced by curcumin. Our results indicate that activation of the DNA damage response by polyphenols might suppress the malignant transformation of prostate cancer. In addition, testosterone, when combined with curcumin, may have suppressive effects on the progression of prostate cancer.

Is a decreased serum testosterone level a risk factor for prostate cancer? A cohort study of korean men

Purpose

To investigate patients who had transrectal ultrasonography (TRUS)-guided prostate biopsy to define the role of the serum testosterone level in predicting prostate cancer risk and its association with a high Gleason score.

Materials and Methods

A total of 568 patients who underwent prostate biopsy were entered in this study. We divided the patients into two groups according to serum testosterone level (median level, 3.85 ng/ml): the high-testosterone group (n=285) and the low-testosterone group (n=283). Multivariate regression analysis was used to define the effect of age, prostate volume, serum prostate-specific antigen (PSA) level and PSA density, and serum testosterone level on the risk of prostate cancer and a high Gleason score.

Results

Baseline characteristics did not differ significantly between the two groups. Compared with the high-testosterone group, the low-testosterone group had a significantly higher prostate cancer incidence (38.9% vs. 29.5%, p=0.018). Factors associated with an increased risk of prostate cancer were increased age (odds ratio [OR]=1.08, 95% confidence interval [CI]=1.25-3.16, p=0.001), a high serum PSA level (OR=3.35, 95% CI=2.63-4.25, p=0.001), a low prostate volume (OR=0.183, 95% CI=0.11-0.30, p=0.001), and a low serum testosterone level (OR=1.99, 95% CI=1.25-3.16, p=0.001). Among these, only the serum PSA level was a strong predictor of high-grade prostate cancer (Gleason score ≥7) (OR=2.19, 95% CI=1.57-2.95, p=0.001).

Conclusions

Patients with lower levels of serum testosterone had a higher risk of prostate cancer than did patients with high serum testosterone. Even though a lower serum testosterone level was a predictor of prostate cancer risk, it was not associated with an increased risk of high-grade prostate cancer.

Relationship between initial PSA density with future PSA kinetics and repeat biopsies in men with prostate cancer on active surveillance

The objective of our study is to examine the correlation between PSA density (PSAd) at the time of diagnosis with PSA velocity (PSAV), PSA doubling time and tumour progression, on repeat biopsy, in men with prostate cancer on active surveillance. Data from 102 patients with clinically localized prostate cancer on active surveillance in the period between 1992 and 2007, who had the necessary parameters available, were collected. PSAd was calculated and correlated with PSAV, PSA doubling time (PSADT), Gleason score at diagnosis and local progression on repeated biopsies. PSAV was 0.64 and 1.31 ng ml^–1 per year (P=0.02), PSADT of 192 and 113 months (P=0.4) for PSAd below and above 0.15, respectively. The rate of detecting high Gleason score (⩾7) at diagnosis was 6 and 23% for PSAd below and above 0.15, respectively. A total of 101 patients underwent at least a second biopsy and the incidence of upgrading was 10 and 31% for PSAd below and above 0.15, respectively (P=0.001). Although low PSAd is an accepted measure for suggesting insignificant prostate cancer, our study expands its role to indicate that PSAd <0.15 may be an additional clinical parameter that may suggest indolent disease, as measured by future PSAV and repeat biopsy over time.

Male infertility and prostate cancer risk: a nested case-control study

The pathogenesis of prostate cancer is unclear, although experimental evidence implicates androgens as playing an important role. Infertile men frequently suffer from some degree of hypogonadism and may hence be hypothesized to be at lower risk of developing prostate cancer than fertile men. To test this hypothesis, we conducted a case-control study nested within "the Malmö Diet and Cancer Study" cohort in Sweden, inviting 661 prostate cancer cases and 661 age-matched controls to participate. Of the 975 (74%) respondents, we excluded 84 childless men with unknown fertility status. Thus, 891 men were included, providing 445 prostate cancer cases and 446 controls. Of these, 841 (94%) men were biological fathers and 50 (6%) men were infertile. Logistic regression showed that the infertile men were at significantly lower risk of being diagnosed with prostate cancer than the fertile men (odds ratio, 0.45; 95% confidence interval, 0.25-0.83). Conditional and unconditional multivariate models, adjusting for socioeconomic, anthropometric, and health-status-related factors, provided similar estimates. We conclude that enduring male infertility is associated with a reduced prostate cancer risk, thus corroborating the theory that normal testicular function, and hence most probably sufficient steroidogenesis, is an important contributing factor to the later development of this malignancy.

The evolutionary impact of androgen levels on prostate cancer in a multi-scale mathematical model

Background

Androgens bind to the androgen receptor (AR) in prostate cells and are essential survival factors for healthy prostate epithelium. Most untreated prostate cancers retain some dependence upon the AR and respond, at least transiently, to androgen ablation therapy. However, the relationship between endogenous androgen levels and cancer etiology is unclear. High levels of androgens have traditionally been viewed as driving abnormal proliferation leading to cancer, but it has also been suggested that low levels of androgen could induce selective pressure for abnormal cells. We formulate a mathematical model of androgen regulated prostate growth to study the effects of abnormal androgen levels on selection for pre-malignant phenotypes in early prostate cancer development.

Results

We find that cell turnover rate increases with decreasing androgen levels, which may increase the rate of mutation and malignant evolution. We model the evolution of a heterogeneous prostate cell population using a continuous state-transition model. Using this model we study selection for AR expression under different androgen levels and find that low androgen environments, caused either by low serum testosterone or by reduced 5α-reductase activity, select more strongly for elevated AR expression than do normal environments. High androgen actually slightly reduces selective pressure for AR upregulation. Moreover, our results suggest that an aberrant androgen environment may delay progression to a malignant phenotype, but result in a more dangerous cancer should one arise.

Conclusions

The model represents a useful initial framework for understanding the role of androgens in prostate cancer etiology, and it suggests that low androgen levels can increase selection for phenotypes resistant to hormonal therapy that may also be more aggressive. Moreover, clinical treatment with 5α-reductase inhibitors such as finasteride may increase the incidence of therapy resistant cancers.

Reviewers

This article was reviewed by Ariosto S. Silva (nominated by Marek Kimmel) and Marek Kimmel.

Circulating steroid hormones in prostate carcinogenesis. Part 1 – Androgens

The aim of this review is to identify circulating steroids associated with prostate cancer (PCa) in bibliographic reports. First, we summarize chronological reports comparing circulating steroid levels in men with a high risk of PCa, such as African-Americans (AAs), with men having a lower risk. Higher testosterone plasma levels in young AA men have been reported. However, the difference between AAs and Caucasians decreases with age. When measured, dihydrotestosterone (DHT) was found to be higher in AAs; however, these results must be taken with caution, as immunological assay of this steroid is difficult. Second, we summarize chronological reports concerning circulating steroids assayed in blood samples drawn several years before a diagnosis of PCa was made, compared to controls. These nested case-control studies did not lead to straightforward conclusions regarding an increase in circulating testosterone. However, large collaborative studies showed a trend of a decrease in plasma sex hormone binding globulin, consequently an increase in bioavailable plasma testosterone in PCa. These nested case-control studies failed to associate plasma DHT levels with PCa risk. Third, we summarize numerous chronological publications relating plasma concentrations, measured at the time of PCa diagnosis. Numerous results showed a decrease in plasma testosterone levels in aggressive PCa (high Gleason score, advanced stage with positive surgical margins). Testosterone levels returned to normal several months after prostatectomy. All plasma hormone assay levels were always carried out using immunological methods. We recommend replacing this methodology by mass spectrometry coupled with gas chromatography or liquid chromatography in these epidemiologic studies.

Association between serum sex hormone levels and prostate cancer: effect of prostate cancer on serum testosterone levels

Androgens are essential for prostatic growth and development, but also play a significant role in the pathogenesis of prostate disease. The traditional view that higher testosterone levels represent a risk factor for prostate cancer (PCa) appears to have little evidentiary support. Some studies have described a relationship between lower testosterone levels and more advanced disease. Serum androgen levels, within a broad range, are thus suggested to show no association with PCa risk, whereas low rather than high serum testosterone levels have been found to be associated with advanced or high-grade disease at the time of PCa diagnosis. Dihydrotestosterone, the principal prostatic androgen, is transformed from testosterone by type 1 and type 2 5alpha-reductase, and therapeutic benefits may thus be potentially achieved through the inhibition of 5alpha-reductase.

Development of highly sensitive quantification method for testosterone and dihydrotestosterone in human serum and prostate tissue by liquid chromatography-electrospray ionization tandem mass spectrometry

We developed highly sensitive detection of testosterone (T) and 5alpha-dihydrotestosterone (DHT) by liquid chromatography-electrospray ionization tandem mass spectrometry using high proton affinitive derivatization of 17beta-hydroxyl group of T and DHT with picolinic acid, mobile phase consisting of MeCN-MeOH-H(2)O-formic acid and conventional octadecylsilica (ODS) column. Purification of the derivatives was carried out using solid-phase extraction with ODS cartridge. By this method, T and DHT were determined simultaneously with limits of quantification (LOQs) of 1 pg/0.2 ml in serum, and T and DHT with LOQs of 0.5 pg and 1 pg/3mg in prostate tissue, respectively, under acceptable assay performance (intra-assay and inter-assay accuracy and precision). The present method provides reliable and reproducible results for quantification of T and DHT in small volumes of serum and prostate samples for diagnosis in prostatic disorders and male climacteric.

Testosterone deficiency syndrome: treatment and cancer risk

Testosterone deficiency syndrome (TDS) can be linked to premature mortality and to a number of co-morbidities (such as sexual disorders, diabetes, metabolic syndrome, ...). Testosterone deficiency occurs mainly in ageing men, at a time when prostate disease (benign or malign) start to emerge. New testosterone preparations via different route of administration appeared during the last decade allowing optimized treatment to these patients. One potential complication of this treatment is the increased risk of prostate and breast cancer. Consequently, the guidelines from the agencies and the institutions, the recommendations of the scientific expert committees and the attitude of the clinicians to who, when and how to treat hypogonadal patients, is very conservative, not to say, highly restrictive. To date, as documented in many reviews on the subject, nothing has been found to support the evidence that restoring testosterone levels within normal range increases the incidence of prostate cancer. In our experience, during a long-term clinical study including 200 hypogonadal patients receiving a patch of testosterone, 50 patients ended 5 years of treatment and no prostate cancer have been reported. In fact, the incidence of prostate cancer in primary or secondary testosterone treated hypogonadal men is lower than the incidence observed in the untreated eugonadal population. However, even if the number of patients treated in well-conducted clinical trials for whom cancer of the prostate has been reported is insignificant (a very few), the observed population is still too small to raise definite conclusions. Low testosterone levels have been reported in patients undergoing radical prostatectomy and the outcomes are of worse diagnostic in this population; at a later stage, testosterone deficiency can be induced by anti hormonal manipulation of patient with a prostate cancer, leading to the symptoms of hypogonadism. The question is to know whether it is justified, in case of profound symptoms, to supplement those patients with testosterone. Some attempts have been made and the results are encouraging: so it is time to re-examine our position and to question about the definite recommendation that patients with prostate cancer should never receive testosterone supplementation therapy; this is already the situation when intermittent androgen blockade is initiated if the biological response is satisfactory. Furthermore, it has been advocated that, under a rigorous surveillance, patients cured of prostate cancer can be treated with testosterone supplementation with beneficial results.

The REDUCE trial: chemoprevention in prostate cancer using a dual 5alpha-reductase inhibitor, dutasteride

Dutasteride, a dual 5alpha-reductase inhibitor, is used in the treatment of benign prostatic hyperplasia (BPH). It reduces serum prostate-specific antigen levels by approximately 50% at 6 months and total prostate volume by 25% after 2 years. Randomized placebo-controlled trials in BPH patients have shown the efficacy of dutasteride in symptomatic relief, improvements in quality of life and peak urinary flow rate. Side effects occurring with dutasteride are decreased libido, erectile dysfunction, ejaculation disorders and gynecomastia. Preliminary data from placebo-controlled BPH trials have shown a decrease in the detection of prostate cancer in patients treated with dutasteride, although these studies were not designed to look at this issue. Dutasteride differs from finasteride in that it inhibits both isoenzymes of 5alpha-reductase, type I and type II. The landmark Prostate Cancer Prevention Trial at the end of the 7-year study demonstrated a 24.8% reduction in the incidence of prostate cancer in the finasteride group compared with placebo. However, a 25.5% increase in the prevalence of high-grade Gleason tumors has been observed, the clinical significance of which has been debated. Preliminary data suggest a decrease in prostate cancer incidence in dutasteride-treated patients and demonstrate type I alphareductase enzyme expression in prostate cancer. As a result, dutasteride is being investigated for prostate cancer prevention in the ongoing Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial, which is discussed here.

The role of testosterone in the pathogenesis of prostate cancer

Relationships between androgenic hormones and prostatic tissue growth are complex. It is certainly true that the prostate will not develop without androgens and the gland will atrophy if androgen support is withdrawn. The hormonal hypothesis remains one of the most important hypotheses in the etiology of prostate cancer (PCa), and efforts are continuing to improve the understanding of androgen actions in PCa. Although evidence from epidemiological studies of associations between circulating levels of androgens and PCa risk has been inconsistent, the traditional view that higher testosterone (T) levels represent a risk factor for PCa appears to have little evidentiary support. Reinvestigation of the relationship between T and PCa seems important and necessary if a new, clinically and scientifically rewarding concept is to be constructed. The present review considers the metabolism and intraprostatic action of T, epidemiological evidence, and the association between T and PCa risk.

Effect of exercise on serum sex hormones in men: a 12-month randomized clinical trial

PURPOSE

The effect of exercise on androgens in middle-aged to older men is poorly understood, and it could have implications for several aspects of health. This analysis was conducted to examine the effects of long-term aerobic exercise on serum sex hormones in middle-aged to older men.

METHODS

One hundred two sedentary men, ages 40-75 yr, were randomly assigned to a 12-month exercise intervention or a control group (no change in activity). The combined facility- and home-based exercise program consisted of moderate/vigorous-intensity aerobic activity for 60 min.d(-1), 6 d.wk(-1). Serum concentrations of testosterone, free testosterone, dihydrotestosterone (DHT), 3alpha-androstanediol glucuronide (3alpha-Diol-G), estradiol, free estradiol, and sex hormone-binding globulin (SHBG) were measured at baseline, 3, and 12 months.

RESULTS

Exercisers trained a mean of 370 min.wk(-1) (102% of goal), with only two dropouts. Cardiopulmonary fitness (.VO(2max)) increased 10.8% in exercisers and decreased by 1.8% in controls (P < 0.001). DHT increased 14.5% in exercisers versus 1.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.6% above baseline in exercisers versus a 3.1% decrease in controls (P = 0.03). SHBG increased 14.3% in exercisers versus 5.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.9% above baseline in exercisers versus 4.0% in controls (P = 0.13). There were significant trends toward increasing DHT and SHBG, with greater increases in .VO(2max) at 3 and 12 months in exercisers. No statistically significant differences were observed for testosterone, free testosterone, 3alpha-Diol-G, estradiol, or free estradiol in exercisers versus controls.

CONCLUSIONS

A year-long, moderate-intensity aerobic exercise program increased DHT and SHBG, but it had no effect on other androgens in middle-aged to older men.

Intra-prostatic androgen levels during various androgen-blockade regimens

Androgens are heavily involved in the development of prostate cancer. This article reviews the scenario of the androgen environment and androgen metabolism in the prostate during androgen-deprivation therapy (ADT) in patients with prostate cancer. Ways of altering the intra-prostatic androgen milieu during various androgen-blockade regimens include surgical castration, luteinizing hormone-releasing hormone analogues to block androgen secretion by the testes, anti-androgens, and 5alpha-reductase inhibitors. The levels of androgen precursors in the blood are different under different ADT regimens, and the androgen levels in the prostate also vary according to the ADT used. This may affect the therapeutic effect of ADT. We therefore discuss the subject of prostatic androgen levels during various androgen-blockade regimens, and we describe the prospects for the future of ADT.

Mechanisms linking physical activity with cancer

About 25% of cancer cases globally are due to excess weight and a sedentary lifestyle. Physical activity may decrease risk for various cancers by several mechanisms, including decreasing sex hormones, metabolic hormones and inflammation, and improving immune function. The level of physical activity might also be associated with prognosis among individuals with cancer. Randomized clinical trials have shown that physical activity interventions can change biomarkers of cancer risk. Observational studies can also provide useful information on mechanisms that might link physical activity to cancer.

The Change in the Dihydrotestosterone Level in the Prostate Before and After Androgen Deprivation Therapy in Connection With Prostate Cancer Aggressiveness Using the Gleason Score

PURPOSE

We investigated the change in dihydrotestosterone in the prostate during androgen deprivation therapy in connection with prostate cancer aggressiveness using the Gleason score.

MATERIALS AND METHODS

A total of 28 patients with clinically localized prostate cancer who were treated with androgen deprivation therapy for 6 months were enrolled in this study. Dihydrotestosterone in the prostate and serum were analyzed using liquid chromatography/electrospray ionization-mass spectrometry after polar derivatization before and after androgen deprivation therapy.

RESULTS

The change in dihydrotestosterone during androgen deprivation therapy in the prostate with Gleason score 7 to 10 prostate cancer was significantly smaller than that in the prostate with Gleason score 6 or less (p = 0.016). There were no significant differences between patients with Gleason score 7 to 10 prostate cancer and patients with Gleason score 6 or less in dihydrotestosterone in the prostate, in serum androgens and in serum androgen ratios before and after androgen deprivation therapy.

CONCLUSIONS

Low dihydrotestosterone in the prostate is probably sufficient to propagate the growth of aggressive prostate cancer. Furthermore, the prostate with aggressive prostate cancer can produce androgens from adrenal precursors more autonomously than the prostate with nonaggressive prostate cancer under a low testosterone environment with testicular suppression.

Prostate cancer risk in testosterone-treated men

Men with classical androgen deficiency have reduced prostate volume and blood prostate-specific antigen (PSA) levels compared with their age peers. As it is plausible that androgen deficiency partially protects against prostate disease, and that restoring androgen exposure increases risk to that of eugonadal men of the same age, men using ART should have age-appropriate surveillance for prostate disease. This should comprise rectal examination and blood PSA measurement at regular intervals (determined by age and family history) according to the recommendations, permanently revisited, published by ISSAM, EAU, Endocrine Society.... Testosterone replacement therapy is now being prescribed more often for aging men, the same population in which prostate cancer incidence increases; it has been suggested that administration in men with unrecognised prostate cancer might promote the development of clinically significant disease. In hypogonadal men who were candidates for testosterone therapy, a 14% incidence of occult cancer was found. A percentage (15.2%) of prostate cancer has been found in the placebo group (with normal DRE and PSA) in the prostate cancer prevention study investigating the chemoprevention potential of finasteride. The hypothesis that high levels of circulating androgens is a risk factor for prostate cancer is supported by the dramatic regression, after castration, of tumour symptoms in men with advanced prostate cancer. However these effects, seen at a very late stage of cancer development, may not be relevant to reflect the effects of variations within a physiological range at an earlier stage. Data from all published prospective studies on circulating level of total and free testosterone do not support the hypothesis that high levels of circulating androgens are associated with an increased risk of prostate cancer. A study on a large prospective cohort of 10,049 men, contributes to the gathering evidence that the long standing "androgen hypothesis" of increasing risk with increasing androgen levels can be rejected, suggesting instead that high levels within the reference range of androgens, estrogens and adrenal androgens decrease aggressive prostate cancer risk. Indeed, high-grade prostate cancer has been associated with low plasma level of testosterone. Furthermore, pre-treatment total testosterone was an independent predictor of extraprostatic disease in patients with localized prostate cancer; as testosterone decreases, patients have an increased likelihood of non-organ confined disease and low serum testosterone levels are associated with positive surgical margins in radical retropubic prostatectomy. A clinical implication of these results concerns androgen supplementation which has become easier to administer with the advent of transdermal preparations (patch or gel) that achieve physiological testosterone serum levels without supra physiological escape levels. During the clinical development of a new testosterone patch in more than 200 primary or secondary hypogonadal patients, no prostate cancer was diagnosed.