Luminal breast cancer identity is determined by loss of glucocorticoid receptor activity

Glucocorticoid receptor (GR) is a transcription factor that plays a crucial role in cancer biology. In this study, we utilized an in silico-designed GR activity signature to demonstrate that GR relates to the proliferative capacity of numerous primary cancer types. In breast cancer, the GR activity status determines luminal subtype identity and has implications for patient outcomes. We reveal that GR engages with estrogen receptor (ER), leading to redistribution of ER on the chromatin. Notably, GR activation leads to upregulation of the ZBTB16 gene, encoding for a transcriptional repressor, which controls growth in ER-positive breast cancer and associates with prognosis in luminal A patients. In relation to ZBTB16's repressive nature, GR activation leads to epigenetic remodeling and loss of histone acetylation at sites proximal to cancer-driving genes. Based on these findings, epigenetic inhibitors reduce viability of ER-positive breast cancer cells that display absence of GR activity. Our findings provide insights into how GR controls ER-positive breast cancer growth and may have implications for patients' prognostication and provide novel therapeutic candidates for breast cancer treatment.

Abstract BS1-2: A new perspective on androgen receptor action in estrogen receptor-α positive breast cancer

Resistance to estrogen receptor alpha (ER) target therapies is the major cause of breast cancer death. Therapeutic engagement of steroid receptors that impinge on, but do not ablate, ER signalling is an emerging new treatment strategy. The AR is expressed in the majority of breast tumors and represents an exceptional therapeutic target, especially as a range of drugs including AR agonists, antagonists and selective AR modulators (SARMs) are available. Interest in targeting AR for treatment of breast cancer has escalated over the past decade. Despite clinical correlations and preclinical studies supporting a protective role for AR in breast cancer, especially in ER-positive disease, enthusiasm was largely directed toward antagonizing AR with anti-androgenic drugs used to treat men with prostate cancer, a disease definitively driven by oncogenic AR activity. While some pre-clinical studies supported use of an AR antagonist for ER-positive breast cancer, this strategy has had minimal success in clinical trials. Our most recent preclinical studies using a diverse range of in vivo breast cancer models (Hickey et al, Nature Medicine 2021) provides compelling evidence for (i) AR being a tumor suppressor in ER+ breast cancer, and (ii) an AR agonist, not an antagonist, treatment strategy being the optimal therapeutic approach.

Citation Format: W Tilley. A new perspective on androgen receptor action in estrogen receptor-α positive breast cancer. [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr BS1-2.

Abstract OT-09-07: Winpro: A window of opportunity study of endocrine therapy with and without prometrium in postmenopausal women with early stage hormone receptor-positive breast cancer

Background: There is bidirectional interplay between PR and ER in human breast cancers (Lim, Endo Rel Can 2016). Evidence in breast cancer cell lines suggests that dual treatment with estrogen and progesterone compared to estrogen alone leads to reprogramming of ER chromatin binding sites via regulation of 470 genes (Mohammed, Nature 2015). Importantly, there was an additive anticancer effect in preclinical breast cancer models when natural progesterone was combined with standard endocrine therapy; we hypothesize that this combination has activity in women with breast cancer.Trial design: We are conducting a phase II multi-center, randomised, open-label, three-arm study in which 200 postmenopausal women with early-stage ER-positive (ER ≥10%), PR-positive (PR ≥10%), HER2-negative breast cancer will be randomised 1:1:1 to letrozole 2.5mg daily (arm 1); letrozole 2.5mg and prometrium 300mg PO daily (arm 2); or tamoxifen 20mg and prometrium 300mg PO daily (arm 3). Surgery will occur on day 14 after treatment initiation. Eligible subjects must have tumor size ≥10mm on imaging, no history of uterine cancer or venous thromboembolism, and no receipt of other preoperative therapies. The primary objective is to assess the reduction in proliferative marker Ki67 following treatment in either combination arm compared to letrozole alone.Methods: Blood will be collected at baseline and at end of treatment. Tissue samples will be collected from the diagnostic biopsy and at the time of surgery. The primary endpoint is geometric mean reduction of centrally assessed Ki67 expression after two weeks of treatment compared with baseline. Given the expected geometric mean reduction of 76% for aromatase inhibitor alone (Dowsett, J Natl Can Inst 2007) and allowing 4% dropouts, 200 patients provides 80% power to detect an improvement in Ki67 suppression to 92% in either experimental arm with p-value 0.025 for each comparison.The secondary endpoint of safety and tolerability will be assessed (NCI-CTCAE v4.0). Translational endpoints include definition of a predictive gene set biomarker for Ki67 reduction; tumor biomarkers after treatment, including apoptotic markers Bcl-2 and cleaved-caspase3, as well as protein and mRNA expression of ER, PR, AR, FoxA1, and CyclinD1; and levels of estrone, estradiol, E2, progesterone, testosterone, DHT, and DHEAS in serum and finger prick dried blood spot after treatment.Accrual: Enrolment commenced in February 2018 and 70 patients have been randomized from 7 sites to date (1 July 2020). Target accrual is 200 patients enrolled from 8 sites.Contact information: This study is led at The Kinghorn Cancer Centre, St Vincent’s Sydney Hospital Sydney, Australia, and funded by the Cancer Council of NSW and the NHMRC Translational Breast Cancer Project grant. Contact Elgene Lim MBBS FRACP PhD at e.lim@garvan.org.au.

Citation Format: Brandon Lau, Davendra Segara, Andrew Ong, Janne Bingham, Belinda Kiely, Emma-Kate Carson, Julia Chen, Cindy Mak, Sanjay Warrier, Mun Hui, Kate Middleton, Andrew Parker, Bruce Mann, Geoffrey Lindeman, Wayne Tilley, Elgene Lim. Winpro: A window of opportunity study of endocrine therapy with and without prometrium in postmenopausal women with early stage hormone receptor-positive breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-09-07.

Abstract PS18-17: Mdm2 inhibition synergises with endocrine therapy or cdk4/6 inhibition for the treatment of estrogen receptor-positive breast cancer

Background: Resistance to endocrine therapy is a major clinical challenge in the management of estrogen receptor (ER)-positive breast cancer. In this setting p53 is frequently wildtype and its activity may be suppressed via upregulation of its key regulator MDM2. This underlies our rationale to evaluate MDM2 inhibition as a therapeutic strategy in treatment resistant ER-positive breast cancer.

Methods: We used the MDM2 inhibitor NVP-CGM097 to treat in vitro and in vivo models alone and in combination with fulvestrant or palbociclib. We perform cell viability, cell cycle, apoptosis and senescence assays to evaluate antitumor effects in p53 wildtype and p53 mutant ER positive cell lines (MCF-7, ZR75-1, T-47D) and MCF-7 lines resistant to endocrine therapy and to CDK4/6 inhibition. We further assess the drug effects in patient-derived xenograft (PDX) models of endocrine-sensitive and -resistant ER positive breast cancer.

Results: We demonstrate that MDM2 inhibition results in cell cycle arrest and increased apoptosis in p53-wildtype in vitro and in vivo breast cancer models, leading to potent anti-tumour activity. We find that endocrine therapy or CDK4/6 inhibition synergises with MDM2 inhibition but does not further enhance apoptosis. Instead, combination treatments result in profound regulation of cell cycle-related transcriptional programmes, with synergy achieved through increased antagonism of cell cycle progression. Combination therapy pushes cell lines resistant to fulvestrant or palbociclib to become senescent and significantly reduces tumour growth in a fulvestrant resistant patient derived xenograft model.

Conclusions: We conclude that MDM2 inhibitors in combination with ER degraders or CDK4/6 inhibitors represent a rational strategy for treating advanced, endocrine resistant ER-positive breast cancer, operating through synergistic activation of cell cycle co-regulatory programs.

Citation Format: Neil Portman, Heloisa Milioli, Sarah Alexandrou, Rhiannon Coulson, Aliza Yong, Kristine Fernandez, KeeMing Chia, Ensar Halilovic, Davendra Segara, Andrew Parker, Sue Haupt, Ygal Haupt, Wayne Tilley, Alex Swarbrick, Liz Caldon, Elgene Lim. Mdm2 inhibition synergises with endocrine therapy or cdk4/6 inhibition for the treatment of estrogen receptor-positive breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS18-17.

Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction

Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction.

Abstract 2076: Phospholipid profiling of clinical prostate tissues reveals targetable alterations in membrane lipid composition accompanying tumorigenesis

Membranes are unique phospholipid (PL) interfaces that play a central role in cancer cell biology. However, PL composition of clinical tumors, and its dynamic regulation, remains a critical gap in the molecular profiling of this disease. Here, we used mass spectrometry-based spatial imaging and lipidomics to generate PL profiles of clinical prostate tissues upon cancer development and in patient-derived tumor explants (PDEs; n=43) cultured with the current clinical agent enzalutamide. Analysis of more than 100 PL species in tumors and matched normal tissues from 21 patients revealed a complexity of cancer-related changes in the tissue PL landscape. Phosphatidylcholine (PC)-based PLs were the most abundant PL class, and their relative abundance was increased in tumors compared to matched benign tissues. A greater proportion of monounsaturated fatty acid chains was characteristic of PLs in tumors, most evident in the PC and phosphatidylethanolamine (PE) PLs, as was striking elongation of fatty acid chains in the phosphatidylinositol (PI) and phosphatidylserine (PS) classes. The abundance of specific PL species and saturation groups was significantly associated with malignancy in both this and an independent cohort of unmatched patient tissues (n=47). Notably, the PL profile was significantly associated with the ERG molecular subtype and basal proliferative index (Ki67) in tumors. Furthermore, we identified individual PL species that were associated with the antiproliferative response to enzalutamide, in cultured PDEs. In light of these PL features, we proposed acetyl coA carboxylase (ACC) as a novel therapeutic target in prostate cancer. Indeed, blocking lipid biosynthesis and elongation in prostate tumors with an ACC inhibitor (ACCi, PF-05175157) significantly reduced tumor cell proliferation in PDE tissues (n=13), concomitant with increased pACC1 staining and a decreased proportion of longer chain PLs. Our findings suggest that the clinical PCa lipidome is not only a marker of malignant transformation and aggressiveness, but also therapeutic response to enzalutamide. Moreover, defining this unique biology identified further clinically actionable targets that may improve prostate cancer outcomes.

Citation Format: Lisa M. Butler, Chui Yan Mah, Jonas Dehairs, Andrew Vincent, Shadrack Mutuku, Xander Spotbeen, Rajdeep Das, Zeyad Nassar, Luke Selth, Paul Trim, Marten Snel, David Lynn, Lisa Horvath, Wayne Tilley, Margaret Centenera, Johannes Swinnen. Phospholipid profiling of clinical prostate tissues reveals targetable alterations in membrane lipid composition accompanying tumorigenesis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2076.

Targeting CDK2 in cancer: challenges and opportunities for therapy

Cyclin-dependent kinase 2 (CDK2) plays a pivotal part in cell cycle regulation and is involved in a range of biological processes. CDK2 interacts with and phosphorylates proteins in pathways such as DNA damage, intracellular transport, protein degradation, signal transduction, DNA and RNA metabolism and translation. CDK2 and its regulatory subunits are deregulated in many human cancers and there is emerging evidence suggesting CDK2 inhibition elicits antitumor activity in a subset of tumors with defined genetic features. Previous CDK2 inhibitors were nonspecific and limited by off-target effects. The development of new-generation CDK2 inhibitors represents a therapeutic opportunity for CDK2-dependent cancers.

Abstract 112: Patient derived models reveal impact of the tumor microenvironment on therapeutic response

Prostate cancer (PCa) is the most common non-cutanenous cancer and the second leading cause of cancer-related death in American men. Androgen receptor (AR) is a hormone-activated transcription factor that plays an important role in both the development and progression of PCa. Androgen deprivation therapy is a common first-line therapy for disseminated disease. However, virtually all tumors become resistant to such therapy and the tumor recurs. Thus, there is a vital need for the development of novel, more effective drugs. One major hurdle in this aspect is the lack of adequate preclinical models. Current models do not effectively recapitulate the heterogeneity and the microenvironment of human PCa tumors, significantly hindering the ability to accurately predict therapeutic response. Our collaborative group has utilized and characterized a method to culture patient tumors ex vivo, termed Patient Derived Explant (PDE). This approach maintains the integrity of the native tumor microenvironment, tumor tissue morphology, and molecular signaling. Importantly, our PDE model can be manipulated both chemically (drugs/compounds) and genetically (shRNA) in order to determine specific reactions and mechanisms of response on individual tumor growth. Furthermore, with this model we can quantitatively assess drug efficacy on numerous parameters (i.e. AR levels, Ki67 staining, apoptosis screening, and desmoplasmic indices). Data to be discussed will assess the variances in response to AR-directed therapeutics and underlying mechanisms of action, while also utilizing TME characteristics as a means to predict response to therapy. In addition, we can potentially identify clinically relevant subpopulations of patients and molecularly profile their cultured tissue to uncover new pathways for therapeutic intervention. Thus, the PDE model allows for a comprehensive evaluation of individual tumors in their native microenvironment to ultimately develop more effective therapies. This study will have transformative clinical impact discerning novel metrics for the inclusion of precision medicine for advanced PCa.

Citation Format: Ayesha A. Shafi, Matthew J. Schiewer, Renée de Leeuw, Emanuela Dylgjeri, Peter A. McCue, Neelima Shah, Leonard Gomella, Costas Lallas, Edouard Trabulsi, Margaret Centerera, Theresa Hickey, Lisa Butler, Ganesh Raj, Wayne Tilley, Edna Cukierman, Karen E. Knudsen. Patient derived models reveal impact of the tumor microenvironment on therapeutic response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 112.

Abstract P6-20-04: Activation of AR inhibits growth of endocrine-resistant breast cancer

Introduction

Resistance to endocrine therapy is a major clinical problem in estrogen receptor positive (ER+) breast cancer. The androgen receptor (AR) is expressed in ˜90% of all ER+ breast cancers and high expression of AR is associated with a better patient outcome in this subtype. In agreement, AR activation in breast cancer cell line models reduces proliferation of cells via antagonism of ER signaling. However, uncertainty surrounding the role of AR in endocrine resistance is reflected in current clinical trials in which both AR agonists and antagonists are being investigated. In this study, we sought to investigate the optimal approach in targeting AR in endocrine-resistant breast cancer.

Methods

We evaluated the consequences of AR activation, using AR cognate ligand 5α-dihydrotestosterone (DHT) and selective AR modulator enobosarm, and AR antagonism using enzalutamide on in vitro and in vivo models of endocrine-resistance. The efficacy of these AR modulators were assessed in vitro using tamoxifen-resistant (TamR) and long-term estrogen derived (LTED) models of MCF7 cells, and in vivo using ESR1 mutant E2-dependent (HCI-005) and ESR1 wild-type E2-independent (Gar15-13) endocrine-resistant PDX models

Results

Treatment with DHT and enobosarm inhibited the growth of MCF7 TamR and LTED cells but enzalutamide had no effect. AR activation was associated with loss of ER in MCF7 TamR cells and loss of ER-regulated PR expression in MCF7 LTED which suggests that this growth suppression was mediated through the antagonism of ER signaling. Notably, an additive anti-proliferative effect was observed with the combination of enobosarm and CDK4/6 inhibitor palbocilib in the MCF7 TamR cells. A similar pattern was observed in vivo with DHT strongly inhibiting the proliferation of both PDX models. Enobosarm similarly suppressed the proliferation of HCI-005, and to a lesser extent in Gar15-13. The benefit of enobosarm in Gar15-13 was significant given that this model is fulvestrant-resistant. Antagonizing AR with enzalutamide had no effect on growth of Gar15-13 model, similar to our in vitro data. AR agonists reduced expression levels of ER and PR in HCI-005, and transcriptomic analysis of AR agonist-treated Gar15-13 identified significant negative enrichment of genes related to proliferation and estrogen response. These observations indicate that the growth-suppressive effects of AR activation in vivo were mediated through inhibiting ER signaling. We identified an AR gene signature, through RNA-seq analysis of DHT-treated Gar15-13 PDX, which is strongly associated with good outcome in the METABRIC dataset, supporting the hypothesis that an active canonical AR signaling is tumor suppressive in both endocrine-sensitive and -resistant disease contexts. Lastly, we present in vivo data demonstrating enhanced suppression of Ki-67 with the combination of enobosarm and palbociclib in the Gar15-13 PDX.

Conclusion

We have demonstrated that activating AR is an effective therapeutic approach in endocrine-resistant breast cancer, and the combination of an AR agonist with a CDK4/6 inhibitor warrants further investigation in this breast cancer subtype.

Citation Format: Chia KM, Milioli H, Portman N, Laven-Law G, Yong A, Swarbrick A, Caldon L, Tilley W, Hickey T, Lim E. Activation of AR inhibits growth of endocrine-resistant breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-20-04.

Abstract OT1-01-03: The WinPro study: A window of opportunity study of endocrine therapy with and without prometrium in postmenopausal women with early stage hormone receptor-positive breast cancer

Background

There is bidirectional interplay between PR and ER in human breast cancers (Lim et al, Endo Rel Can 2016). There is evidence for a reprogramming of ER chromatin binding sites with 470 genes differentially regulated by dual treatment with estrogen plus progestogen compared to estrogen alone in breast cancer cell lines (Mohammed et al, Nature 2015). Functionally, there was an additive anti-cancer effect with the addition of natural progesterone to endocrine therapy in preclinical breast cancer models.

Trial Design

This is a phase II multi-site, randomised, open-label, three-arm, study in 200 postmenopausal women with early-stage ER+, PR+, HER2-negative breast cancer. Eligible patients will be randomised 1:1:1 to receive 14 days of intervention with either letrozole 2.5mg PO daily (arm 1), letrozole 2.5mg + prometrium 300mg PO daily (arm 2) or tamoxifen 20mg + prometrium 300mg PO daily (arm 3), between diagnosis of breast cancer and definite surgery.

Australian Clinical Trials Registry: ACTRN1261800092813

Eligibility Criteria

Inclusion Criteria

a) Histologically confirmed ER+ and PR+ breast cancers (≥10% positive staining cells)

b) HER2/CEP17 ratio of <2 and mean HER2 copy number <6 (ASCO CAP 2013 guidelines)

c) Tumour size ≥1cm on ultrasound and/or mammogram

d) Aged ≥18 years

Exclusion Criteria

a) Currently on hormone therapies (HRT and OCP)

b) Locally advanced/inoperable and inflammatory breast cancer

c) Clinical evidence of metastatic disease

d) Received other preoperative systemic therapies

e) Nut allergy (prometrium contains peanut oil)

f) Prior history of uterine cancer, deep vein thrombosis, pulmonary embolism or clotting disorder

g) Women who are pregnant/breast feeding

Specific Aims

a) Primary Endpoint

The geometric mean suppression of the centrally assessed proliferation marker Ki67, after two weeks of intervention, compared with baseline. This will be obtained by comparing the mean difference in Ki67 staining between pre and post-treated samples in each intervention arm.

b) Secondary Endpoint

Safety and tolerability of combination therapy (NCI-CTCAE v4.0)

c) Translational Endpoints

1. Define a gene set as a predictive biomarker for a reduction in Ki67

2. Evaluate changes in the apoptotic markers Bcl-2 and Caspase 3 in the tumors following intervention

3. Evaluate changes in ER, PR, AR, FoxA1, Cyclin D1 protein and mRNA expression in the tumors following intervention

Statistical Methods

The IMPACT study reported a geometric mean reduction in Ki67 after 2 weeks of preoperative tamoxifen of 59.5% and anastrazole of 76% (Dowsett et al, JNCI 2007). This allows estimation of power to detect differences between Arm 1 and either Arm 2 or Arm 3 with a p-value of 0.025. For the third possible comparison of Arm 2 vs Arm 3, there is no prior evidence, therefore this as a purely exploratory comparison. With a total trial recruitment of 200 and allowing 4% dropouts, this would give 80% power to detect an improvement in Ki67 suppression from 76% in the letrozole alone control arm to 92% in either experimental arm.

Accrual

Present: 5 (1 site open)

Target: 200 (8 sites total)

Contact Information

Elgene Lim, MBBS, FRACP, PhD. e.lim@garvan.com.au

Citation Format: Carson E, Segara D, Parker A, O'Toole S, Coates A, Mann B, Lindeman G, Tilley W, Lim E. The WinPro study: A window of opportunity study of endocrine therapy with and without prometrium in postmenopausal women with early stage hormone receptor-positive breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT1-01-03.

Author Correction: Association analyses of more than 140,000 men identify 63 new prostate cancer susceptibility loci

In the version of this article initially published, the name of author Manuela Gago-Dominguez was misspelled as Manuela Gago Dominguez. The error has been corrected in the HTML and PDF version of the article.

Cyclin-Dependent Kinase 2 Inhibitors in Cancer Therapy: An Update

Cyclin-dependent kinase 2 (CDK2) drives the progression of cells into the S- and M-phases of the cell cycle. CDK2 activity is largely dispensable for normal development, but it is critically associated with tumor growth in multiple cancer types. Although the role of CDK2 in tumorigenesis has been controversial, emerging evidence proposes that selective CDK2 inhibition may provide a therapeutic benefit against certain tumors, and it continues to appeal as a strategy to exploit in anticancer drug development. Several small-molecule CDK2 inhibitors have progressed to the clinical trials. However, a CDK2-selective inhibitor is yet to be discovered. Here, we discuss the latest understandings of the role of CDK2 in normal and cancer cells, review the core pharmacophores used to target CDK2, and outline strategies for the rational design of CDK2 inhibitors. We attempt to provide an outlook on how CDK2-selective inhibitors may open new avenues for cancer therapy.

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

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

Association analyses of more than 140,000 men identify 63 new prostate cancer susceptibility loci

Genome-wide association studies (GWAS) and fine-mapping efforts to date have identified more than 100 prostate cancer (PrCa)-susceptibility loci. We meta-analyzed genotype data from a custom high-density array of 46,939 PrCa cases and 27,910 controls of European ancestry with previously genotyped data of 32,255 PrCa cases and 33,202 controls of European ancestry. Our analysis identified 62 novel loci associated (P < 5.0 × 10-8) with PrCa and one locus significantly associated with early-onset PrCa (≤55 years). Our findings include missense variants rs1800057 (odds ratio (OR) = 1.16; P = 8.2 × 10-9; G>C, p.Pro1054Arg) in ATM and rs2066827 (OR = 1.06; P = 2.3 × 10-9; T>G, p.Val109Gly) in CDKN1B. The combination of all loci captured 28.4% of the PrCa familial relative risk, and a polygenic risk score conferred an elevated PrCa risk for men in the ninetieth to ninety-ninth percentiles (relative risk = 2.69; 95% confidence interval (CI): 2.55-2.82) and first percentile (relative risk = 5.71; 95% CI: 5.04-6.48) risk stratum compared with the population average. These findings improve risk prediction, enhance fine-mapping, and provide insight into the underlying biology of PrCa1.

Fine-mapping of prostate cancer susceptibility loci in a large meta-analysis identifies candidate causal variants

Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling.

An analysis of multiple biomarkers to better predict prostate cancer metastasis and death after radical prostatectomy

54

Background: Identification of potentially lethal disease at the time of diagnosis with localized prostate cancer (PCa) remains a significant clinical issue despite a plethora of candidate biomarkers. This study evaluates a range of biomarkers previously associated with biochemical relapse (BR) in localized PCa to determine whether a combined expression model can improve detection of clinically significant cases. Methods: The Australian PCa Research Centre NSW has completed 23 studies of molecular biomarkers associated with BR in a well-described localized PCa cohort (n=324, median followup 16 years). 12 studies were excluded due to missing data. Each biomarker was analyzed as a marker for metastatic-free survival (MFS) and prostate cancer specific survival (PCSS) and then used to develop a prognostic model for clinical outcomes incorporating clinico-pathological factors. This model is currently being validated in an independent cohort. Results: The PCa cohort experienced 39 metastatic relapses (12%) and 23 PCa deaths (7%). Of 12 biomarkers (AR, AZPG1, C0S, Cyclin D1a, Cyclin D1b, E6AP, H3K18Ac, H3K4me2, Ki67, p53, PML, SGTA) assessed, only AZGP1 and Ki67 were associated with MFS (HR 2.9, 95% CI, 1.4-5.6; P=0.002, and HR 1.2, 95% CI, 1.0-1.4; P=0.03, respectively) and PCSS (HR 4.2, 95% CI, 1.7-10.5; P=0.002; and HR 1.2, 95% CI, 1.0-1.5; P=0.04, respectively). The combined panel of AZGP1 and Ki67 was an independent predictor of MFS (HR 1.9, 95% CI, 1.1-3.2; P=0.01), and PCSS (HR 3.3, 95% CI, 1.5-7.3; P=0.002) when modeled with known clinicopathological variables. The panel was more robust in predicting MFS and PCSS compared to the individual biomarkers alone and superior to other prognostic models (See table). Data from the validation cohort will be available for the meeting. Conclusions: Our novel signature of AZPG1 and Ki67 improves existing prognostication tools in predicting PCa metastasis and death. [Table: see text]

Role of Androgen Receptor Variants in Prostate Cancer: Report from the 2017 Mission Androgen Receptor Variants Meeting

CONTEXT

Although a number of studies have demonstrated the importance of constitutively active androgen receptor variants (AR-Vs) in prostate cancer, questions still remain about the precise role of AR-Vs in the progression of castration-resistant prostate cancer (CRPC).

OBJECTIVE

Key stakeholders and opinion leaders in prostate cancer convened on May 11, 2017 in Boston to establish the current state of the field of AR-Vs.

EVIDENCE ACQUISITION

The meeting "Mission Androgen Receptor Variants" was the second of its kind sponsored by the Prostate Cancer Foundation (PCF). This invitation-only event was attended by international leaders in the field and representatives from sponsoring organizations (PCF and industry sponsors). Eighteen faculty members gave short presentations, which were followed by in-depth discussions. Discussions focused on three thematic topics: (1) potential of AR-Vs as biomarkers of therapeutic resistance; (2) role of AR-Vs as functionally active CRPC progression drivers; and (3) utility of AR-Vs as therapeutic targets in CRPC.

EVIDENCE SYNTHESIS

The three meeting organizers synthesized this meeting report, which is intended to summarize major data discussed at the meeting and identify key questions as well as strategies for addressing these questions. There was a critical consensus that further study of the AR-Vs is an important research focus in CRPC. Contrasting views and emphasis, each supported by data, were presented at the meeting, discussed among the participants, and synthesized in this report.

CONCLUSIONS

This article highlights the state of knowledge and outlines the most pressing questions that need to be addressed to advance the AR-V field.

PATIENT SUMMARY

Although further investigation is needed to delineate the role of androgen receptor (AR) variants in metastatic castration-resistant prostate cancer, advances in measurement science have enabled development of blood-based tests for treatment selection. Detection of AR variants (eg, AR-V7) identified a patient population with poor outcomes to existing AR-targeting therapies, highlighting the need for novel therapeutic agents currently under development.

Abstract LB-109: PDeX (Patient Derived eXplant) models to determine the basis for response to targeted agents in prostate cancer

Prostate cancer (PCa) is the most common non-cutanenous cancer and the third leading cause of cancer-related death in American men. Androgen receptor (AR) is a hormone-activated transcription factor that plays an important role in both the development and progression of PCa. Androgen deprivation therapy is a common first-line therapy for disseminated disease. However, virtually all tumors become resistant to such therapy and the tumor recurs. Thus, there is a vital need for the development of novel, more effective drugs. One major hurdle in this aspect is the lack of adequate preclinical models. Current models do not effectively recapitulate the heterogeneity and the microenvironment of human PCa tumors, significantly hindering the ability to accurately predict therapeutic response. Our collaborative group has utilized and characterized a method to culture patient tumors ex vivo, termed Patient Derived eXplant (PDeX). This approach maintains the integrity of the native tumor microenvironment, tumor tissue morphology, and molecular signaling. Importantly, our PDeX model can be manipulated both chemically (drugs/compounds) and genetically (shRNA) in order to determine specific reactions and mechanisms of response on individual tumor growth. Furthermore, with this model we can quantitatively assess drug efficacy on numerous parameters (i.e. AR levels, Ki67 staining, apoptosis screening, and desmoplasmic indices). Data to be discussed will assess the variances in response to AR-directed therapeutics and underlying mechanisms of action, while also utilizing TME characteristics as a means to predict response to therapy. In addition, we can potentially identify clinically relevant subpopulations of patients and molecularly profile their cultured tissue to uncover new pathways for therapeutic intervention. Thus, the PDeX model allows for a comprehensive evaluation of individual tumors in their native microenvironment to ultimately develop more effective therapies. This study will have transformative clinical impact discerning novel metrics for the inclusion of precision medicine for advanced PCa.

Citation Format: Ayesha A. Shafi, Matthew J. Schiewer, Renee de Leeuw, Peter A. McCue, Leonard G. Gomella, Costas D. Lallas, Edouard J. Trabulsi, Theresa Hickey, Neelima Shah, Edna Cukierman, Lisa M. Butler, Wayne Tilley, Ganesh Raj, Karen E. Knudsen. PDeX (Patient Derived eXplant) models to determine the basis for response to targeted agents in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-109. doi:10.1158/1538-7445.AM2017-LB-109

Abstract LB-003: Androgen-regulated proteome reveals a therapeutically relevant androgen receptor coactivator target in prostate cancer

Resistance to androgen deprivation therapy (ADT) and the development of castration resistant prostate cancer (CRPC) remains a major challenge in the treatment of advanced prostate cancer (PCa). Elucidation of resistance mechanisms leading to CRPC is essential to develop novel therapeutic interventions. Using a systems biology approach, we interrogated the androgen-regulated proteome and identified a mitotic Kinase as a novel androgen regulated kinase in PCa. The kinase was shown to be androgen-regulated in PCa and its nuclear localisation significantly increased in CRPC and was associated with biochemical relapse. Interestingly, the Kinase interacted directly with the amino terminus transactivation and carboxy terminus ligand binding domain of androgen receptor (AR), resulting in stabilisation of AR protein and its activity. The AR-driven global transcriptional program was regulated by this coactivator kinase including pathways involved in tumour invasion and metastasis. The inhibition of the kinase function decreased AR levels and activity, and slowed growth of PCa cell lines and human PCa explants. Thus the mitotic kinase is a novel AR-Stablised kinase with potential for clinical applications as both a candidate biomarker of PCa progression and a therapeutic target in advanced disease.

Citation Format: Mohammad Asim, Charlie Massie, Anne Warren, Katarina Luko, Brinder Chohan, Suraj Menon, Ajoeb Baridi, Folake Orafidiya, Wanfeng Zhao, Carlos Escriu, Hisham Mohammed, Clive D’Santos, Xiaoping Yang, Chris Taylor, Arham Qureshi, Kate Watt, Vincent Zecchini, Luke Selth, Scott Dehm, Ian Mills, Jason Carroll, Wayne Tilley, Iain McEwan, Aria Baniahmad, David Neal. Androgen-regulated proteome reveals a therapeutically relevant androgen receptor coactivator target in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-003.

Evaluation of Testosterone Supplementation during Anastrozole Therapy in a Breast Explant Model

Background: Aromatase inhibitors (AI) are currently used as first line adjuvant therapy for postmenopausal women with estrogen receptor (ER) positive breast cancer. Side effects of AI therapy, such as arthralgia, can cause significant patient discomfort leading to compliance issues. This may be exacerbated by low tissue testosterone (T), which is naturally lower post-menopause and may be decreased further following chemotherapy. T supplementation has emerged as a potential means to treat AI-associated arthralgia and has generated favourable results in a phase II clinical trial (NCT00497458). However, T replacement in breast cancer had been contraindicated until the advent of powerful 3rd generation AIs such as anastrozole. AIs are highly efficacious in blocking conversion of T to estrogen, thereby increasing the potential for 5α-reduction of T to its more active tissue form, 5α-dihydrotestosterone (DHT), which counterbalances estrogen induced proliferative effects in hormonally sensitive breast tumors1. Our objective was to test the effects of T supplementation during AI administration on tumor growth in a human breast explant system.Materials and Methods: Fresh breast tumor samples collected from 17 post-menopausal women were cut into 3 mm3 pieces, cultured for 24h on gelatine sponges submersed in culture media with 10% steroid depleted fetal calf serum and treated with vehicle (control), T (5nM) and/or AI (25ng/ml). Tissues were stained with antibodies for ER, progesterone receptor (PR), androgen receptor (AR), and Ki67, a marker of cell proliferation that has been used to predict the outcome of therapy with anastrozole2. Tissue sections were scanned using a high resolution image scanner (NanoZoomer) and the percent Ki67 positive cells was determined by counting at least 2000 cells per slide.Results: All tumor tissues were positive (&gt;30%) for ER, AR and PR, with the exception of 1 tumor that lacked PR. As expected for primary tissues, percent Ki67 positivity (mean; range) in the control was highly variable (6.45; 1-43.2). Tissue responses to T (7.9; 0.1-46), AI (6.06; 1.4-35.3), and T+AI (4.97; 0.7-26.1) were not significantly different from control (Wilcoxon signed rank test). However, the combination of T+AI showed a trend towards reduced Ki67 positivity compared to AI alone (p=0.07). In two patients T significantly increased Ki67 positivity by 2-4 fold, and in both instances this stimulatory effect of T was reduced to or below control values by treatment with AI.Discussion: Our results suggest that T supplementation during adjuvant AI therapy does not compromise AI-mediated inhibition of breast tumor growth. Indeed, combined therapy with T and AI may further enhance tumor suppression through elevation of DHT levels in the breast. This finding supports the clinical potential of T supplementation in post-menopausal women on adjuvant AI therapy to prevent or relieve AI-associated side effects.1. Peters A et al Cancer Res (In Press)2. Dowsett M et al JNCI 2007

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4089.

166. MATERNAL OBESITY IS ASSOCIATED WITH AN INCREASED INCIDENCE OF PROSTATE ABNORMALITIES IN ADULT RAT OFFSPRING

The World Health Organization has stated that 75% of adults worldwide are overweight, and in Australia nearly 25% of men are obese. Obesity is associated with an increased risk of cardiovascular disease, type 2 diabetes and cancer, with 30 to 40% of the latter possibly preventable by maintaining a healthy weight (The International Association for the Study of Obesity). Prostate cancer is the most commonly diagnosed cancer in men and there is increasing evidence that obesity increases the risk of prostate cancer mortality. High birth weight, an indication of excess nutrition during foetal development, has been associated with an increased risk of childhood and adult obesity, and for cancer. Using an animal model, we investigated whether obese mothers are more likely to have obese sons who are at an increased risk of developing prostate abnormalities and thus prostate cancer, in adulthood. Female rats were fed with either a control diet (4g fat/kg) or high fat diet (100g fat/kg) from before mating and throughout pregnancy. Prostate tissues were collected from the male offspring at 90 days (post-puberty) and 180 days (young adult). Histological analysis of the day 90 prostates identified hyperplasia in 100% of the ventral lobes (VL) and 64% of the dorsolateral lobes (DLP) in offspring of the maternal high fat group compared to 0% in each respectively, in those of the maternal control diet group. The VL is the most hormone sensitive prostate lobe of the rat, while the DLP is considered the equivalent of the human peripheral zone, the region from which the majority of human prostate cancers arise. These results suggest for the first time that maternal high fat diet may induce prostate abnormalities in male offspring that may in turn, predispose to an increased risk of prostate cancer in later life.

415. Increased expression of an androgen receptor regulated gene, kit ligand, in polycystic ovaries

Polycystic ovaries (PCO) are induced by pathological or pharmacological female androgen excess, but the role of the androgen receptor (AR) in the pathogenesis of PCO is unknown. We therefore tested the hypothesis that PCO have increased expression of AR or kit ligand (KITL), a cytokine that was recently identified as a candidate AR-regulated gene in the ovary (1). Immunohistochemical analysis of AR and KITL expression was performed on archival paraffin-embedded sections of 8 morphologically normal and 8 polycystic ovaries from women under the age of 40 years. Stained sections were scanned with a NanoZoomer Digital Pathology System and immunoreactivity was qualitatively assessed using a 0-3+ scale, where 3+ represents the most intense staining. Electronic images of follicles at different stages of folliculogenesis were assessed by two independent observers who were blinded to the morphology of the source ovary. Each individual ovary contributed a minimum of 1 follicle per size class and a minimum of 10 follicles per size class were analysed. AR immunoreactivity was present in granulosa cells at all stages of folliculogenesis, in thecal cells of large antral follicles, and in the ovarian stroma. Staining intensity for AR did not differ between normal and polycystic ovaries. KITL expression, summarised in Table 1, was found to be significantly elevated in the oocytes of primordial and primary follicles and in the granulosa cells of follicles at all stages of folliculogenesis. These results show that AR expression is normal in PCO but expression of an AR-regulated gene is increased, potentially due to an excess of androgen hormone that is characteristic of women with PCO. Based on the roles of KITL established by murine studies, increased expression of KITL could explain many of the features of PCO including follicle excess, hyperthecosis and abnormal androgen secretion.

Androgen receptor coregulators and their involvement in the development and progression of prostate cancer

The androgen receptor signaling axis plays an essential role in the development, function and homeostasis of male urogenital structures including the prostate gland although the mechanism by which the AR axis contributes to the initiation, progression and metastatic spread of prostate cancer remains somewhat enigmatic. A number of molecular events have been proposed to act at the level of the AR and associated coregulators to influence the natural history of prostate cancer including deregulated expression, somatic mutation, and post-translational modification. The purpose of this article is to review the evidence for deregulated expression and function of the AR and associated coactivators and corepressors and how such events might contribute to the progression of prostate cancer by controlling the selection and expression of AR targets.

Circulating Steroid Hormones and the Risk of Prostate Cancer

Epidemiologic studies have failed to support the hypothesis that circulating androgens are positively associated with prostate cancer risk and some recent studies have even suggested that high testosterone levels might be protective particularly against aggressive cancer. We tested this hypothesis by measuring total testosterone, androstanediol glucuronide, androstenedione, DHEA sulfate, estradiol, and sex hormone-binding globulin in plasma collected at baseline in a prospective cohort study of 17,049 men. We used a case-cohort design, including 524 cases diagnosed during a mean 8.7 years follow-up and a randomly sampled sub-cohort of 1,859 men. The association between each hormone level and prostate cancer risk was tested using Cox models adjusted for country of birth. The risk of prostate cancer was approximately 30% lower for a doubling of the concentration of estradiol but the evidence was weak (P(trend)=0.07). None of the other hormones was associated with overall prostate cancer (P(trend) >or= 0.3). None of the hormones was associated with nonaggressive prostate cancer (all P(trend) >or= 0.2). The hazard ratio [HR; 95% confidence interval (95% CI)] for aggressive cancer almost halved for a doubling of the concentration of testosterone (HR, 0.55; 95% CI, 0.32-0.95) and androstenedione (HR, 0.51; 95% CI, 0.31-0.83), and was 37% lower for a doubling of the concentration of DHEA sulfate (HR, 0.63; 95% CI, 0.46-0.87). Similar negative but nonsignificant linear trends in risk for aggressive cancer were obtained for free testosterone, estradiol, and sex hormone-binding globulin (P(trend)=0.06, 0.2, and 0.1, respectively). High levels of testosterone and adrenal androgens are thus associated with reduced risk of aggressive prostate cancer but not with nonaggressive disease.

Mutation of the androgen receptor causes oncogenic transformation of the prostate

Recent evidence demonstrates that the androgen receptor (AR) continues to influence prostate cancer growth despite medical therapies that reduce circulating androgen ligands to castrate levels and/or block ligand binding. Whereas the mutation, amplification, overexpression of AR, or cross-talk between AR and other growth factor pathways may explain the failure of androgen ablation therapies in some cases, there is little evidence supporting a causal role between AR and prostate cancer. In this study, we functionally and directly address the role whereby AR contributes to spontaneous cancer progression by generating transgenic mice expressing (i) AR-WT to recapitulate increased AR levels and ligand sensitivity, (ii) AR-T857A to represent a promiscuous AR ligand response, and (iii) AR-E231G to model altered AR function. Whereas transgenes encoding either AR-WT or AR-T857A did not cause prostate cancer when expressed at equivalent levels, expression of AR-E231G, which carries a mutation in the most highly conserved signature motif of the NH2-terminal domain that also influences interactions with cellular coregulators, caused rapid development of prostatic intraepithelial neoplasia that progressed to invasive and metastatic disease in 100% of mice examined. Taken together, our data now demonstrate the oncogenic potential of steroid receptors and implicate altered AR function and receptor coregulator interaction as critical determinants of prostate cancer initiation, invasion, and metastasis.

Androgen metabolic genes in prostate cancer predisposition and progression

Significant evidence implicates androgens in prostate cancer etiology. We review recent data with regard to the association between several allelic variants of specific androgen-metabolic genes and the predisposition to prostate cancer. We also review the emerging evidence regarding the role of genetic variants of these genes as well as the androgen receptor in prostate cancer progression. Based on the prostate cancer paradigm, we propose that a multidisciplinary attack on the problem--involving biochemistry, genetics, pharmacogenetics, endocrinology and molecular epidemiology--may be important for the understanding and successful treatment of complex (in terms of etiology) human diseases.

ELAC2/HPC2 polymorphisms, prostate-specific antigen levels, and prostate cancer

BACKGROUND

The ELAC2 gene has been proposed to be a prostate cancer susceptibility gene and is being referred to as HPC2, in part because three case-control studies suggested that two common polymorphisms (Ser217Leu and Ala541Thr) are associated with risk. However, four subsequent larger studies have not confirmed this association. In five of the seven total studies, subject selection was influenced by prostate-specific antigen (PSA) levels. We examined the association and possible effect of subject selection in a larger study and a meta-analysis.

METHODS

In a population-based study in Australia, 825 case patients and 732 control subjects were genotyped for the Ser217Leu and Ala541Thr polymorphisms of ELAC2. Odds ratios (ORs) for prostate cancer were estimated by unconditional logistic and polytomous regression. A meta-analysis was conducted combining our data with those from seven published studies. The association of genotype with the logarithm of plasma PSA levels in control subjects was analyzed by linear regression.

RESULTS

The ORs for prostate cancer were 0.74 (95% confidence interval [CI] = 0.50 to 1.09) for Leu217 homozygotes and 1.01 (95% CI = 0.68 to 1.50) for Thr541 heterozygotes and homozygotes compared with Ser217 and Ala541 homozygotes, respectively. ORs were not changed by excluding control subjects with elevated PSA levels. Among control subjects, there were no statistically significant associations between genotype frequencies and PSA level for either polymorphism (both P>.4). The meta-analysis gave pooled OR estimates of 1.04 (95% CI = 0.85 to 1.26) for Leu217 homozygotes and 1.18 (OR = 0.98 to 1.42) for Thr541 homozygotes and heterozygotes.

CONCLUSION

There is no evidence that either ELAC2 polymorphism is associated with prostate cancer or PSA level.

Rehabilitation of the burned upper extremity

With the advancement in medical technology and more effective life-sustaining measures, the rehabilitation therapist is faced with the immense task of effectively restoring functional ROM, strength, and mobility and producing a cosmetic result acceptable to the patient. Rehabilitation therapists have a very significant role to play in achieving these goals. The patients and their families come to rely very heavily on the therapists for advice, support, and information both in the acute phase of burn management and, potentially, for years to follow. A concerted team approach is necessary for a satisfactory functional outcome following burn injury.

Functional evaluation of the shoulder following latissimus dorsi muscle transfer

The dynamic muscle function of the shoulder in 26 patients (10 males, 16 females) who underwent a pedicled or free vascularized latissimus dorsi muscle transfer between 1985 and 1991 (mean follow-up, 4.4 yr) was studied. Instrumented muscle testing was performed on the Kinetic Communicator machine (Kin Com) and the Baltimore Therapeutic Equipment (BTE) work simulator. The female unilateral pedicle group (n = 13) showed a significant difference between operated and nonoperated shoulders for both peak torque (power) and work (endurance) measurements of shoulder adduction and extension on the Kin Com (mean ratios operated/nonoperated shoulders, 55% to 69%). They also showed significant differences for work performance on three of four BTE tests (mean ratios, 77% to 84%). The male free vascularized group (n = 10) similarly showed a significant deficit of both peak torque and work for shoulder extension and adduction on the Kin Com (mean ratios, 74% to 84%); however, they showed no deficit on the BTE tests. In conclusion, dynamic muscle tests demonstrate a deficit of muscle power and endurance of shoulder extension and adduction following latissimus dorsi muscle transfer.

Xenografted small cell undifferentiated cancer of prostate: possible common origin with prostatic adenocarcinoma

The first xenograft line of small cell undifferentiated carcinoma of the prostate (UCRU-PR-2) has been established and characterized. The donor tumor and the xenograft share the common morphological and ultrastructural features of small cell undifferentiated carcinoma (including neurosecretory granules) but also elaborate epithelial membrane antigen and carcinoembryonic antigen, in addition to neurone-specific enolase. The line expresses a diploid DNA complement. Androgen and estrogen receptors are not expressed, although prostatic acid phosphatase is present in sera from tumor-bearing mice in low levels. From these studies, we postulate a possible common stem cell origin for adenocarcinoma and small cell undifferentiated carcinoma of the prostate; further studies of a cell line derived from this tumor may clarify the issue.

Effectiveness of ivermectin in the treatment of equine Parascaris equorum and Oxyuris equi infections

Fifteen horses harboring naturally acquired, patent Parascaris equorum and Oxyuris equi infections were equally allotted to 3 treatment groups given (1) injectable vehicle; (2) injectable ivermectin at the dose rate of 200 microgram/kg of body weight; and (3) injectable ivermectin at the rate of 300 microgram/kg. All treatments were given IM in the neck. All animals were killed 14 days after treatment and examined for the targeted nematodes. Regardless of dose rate, ivermectin proved 100% effective in the removal of adult O equi and P equorum infections. Levels of immature P equorum were decreased by 98.5% in both ivermectin-treated groups. Oxyuris equi 4th-stage larval injections were decreased by 95.7% and 99.9% by the 200 and 300 microgram/kg ivermectin treatments, respectively. Adverse reactions to the injections of drug were not seen.

Antiparasitic effectiveness of ivermectin in the horse

By way of a controlled trial, the anthelmintic efficacies of the injectable and paste formulations of ivermectin were evaluated in the horse. Treatment was given at the rate of 200 microgram/kg of body weight. Regardless of formulation, 100% removals were demonstrated for Strongylus vulgaris (intestinal), S edentatus, 2nd and 3rd instars of Gastrophilus nasalis and G intestinalis, "small strongyles," Triodontophorus serratus and T tenuicollis. Adult Cylicocyclus insigne populations were eliminated at the rates of 99.9% and 96.3% by the injectable and paste formulations, respectively. Levels of 4th-stage Cylicocyclus spp larvae, as detected in the luminal contents of the colon, were reduced by 88.3% and 33.2% by the injectable and paste formulations, respectively. There were no adverse tissue or behavioral reactions induced by either preparation of ivermectin.

Anthelmintic activities of ivermectin against gastrointestinal nematodes of cattle

The anthelmintic efficacy of ivermectin, a combined solution of the B1a and B1b fractions of avermectin, was assessed in a controlled trial. Twenty-four yearling calves experiencing naturally acquired, clinical gastrointestinal helminthiasis were evenly divided on the basis of weight into two 12-animal groups. The medicated group was given (subcutaneously) ivermectin at the dose rate of 200 microgram/kg of body weight. The control animals were given the vehicle alone, at an equivalent rate. All animals were killed 14 days later. At necropsy of the calves, gastrointestinal helminth arithmetic means were 178,626 and 575 for the control and the treated groups, respectively, an overall reduction of 99.7%. Nematodes which were present at substantial levels were Ostertagia ostertagi, O lyrata, Trichostrongylus axei, Cooperia punctate, C oncophora, C mcmasteri, and Oesophagostomum radiatum. Anthelmintic activity of ivermectin was excellent regardless of nematode species, sex, or stage of development.