Constitutively active MyD88/CD40 costimulation enhances expansion and efficacy of chimeric antigen receptor T cells targeting hematological malignancies.

Successful adoptive chimeric antigen receptor (CAR) T-cell therapies against hematological malignancies require CAR-T expansion and durable persistence following infusion. Balancing increased CAR-T potency with safety, including severe cytokine-release syndrome (sCRS) and neurotoxicity, warrants inclusion of safety mechanisms to control in vivo CAR-T activity. Here, we describe a novel CAR-T cell platform that utilizes expression of the toll-like receptor (TLR) adaptor molecule, MyD88, and tumor-necrosis factor family member, CD40 (MC), tethered to the CAR molecule through an intentionally inefficient 2A linker system, providing a constitutive signal that drives CAR-T survival, proliferation, and antitumor activity against CD19+ and CD123+ hematological cancers. Robust activity of MC-enhanced CAR-T cells was associated with cachexia in animal models that corresponded with high levels of human cytokine production. However, toxicity could be successfully resolved by using the inducible caspase-9 (iC9) safety switch to reduce serum cytokines, by administration of a neutralizing antibody against TNF-α, or by selecting "low" cytokine-producing CD8+ T cells, without loss of antitumor activity. Interestingly, high basal activity was essential for in vivo CAR-T expansion. This study shows that co-opting novel signaling elements (i.e., MyD88 and CD40) and development of a unique CAR-T architecture can drive T-cell proliferation in vivo to enhance CAR-T therapies.

Two-Dimensional Regulation of CAR-T Cell Therapy with Orthogonal Switches.

Use of chimeric antigen receptors (CARs) as the basis of targeted adoptive T cell therapies has enabled dramatic efficacy against multiple hematopoietic malignancies, but potency against bulky and solid tumors has lagged, potentially due to insufficient CAR-T cell expansion and persistence. To improve CAR-T cell efficacy, we utilized a potent activation switch based on rimiducid-inducible MyD88 and CD40 (iMC)-signaling elements. To offset potential toxicity risks by this enhanced CAR, an orthogonally regulated, rapamycin-induced, caspase-9-based safety switch (iRC9) was developed to allow in vivo elimination of CAR-T cells. iMC costimulation induced by systemic rimiducid administration enhanced CAR-T cell proliferation, cytokine secretion, and antitumor efficacy in both in vitro assays and xenograft tumor models. Conversely, rapamycin-mediated iRC9 dimerization rapidly induced apoptosis in a dose-dependent fashion as an approach to mitigate therapy-related toxicity. This novel, regulatable dual-switch system may promote greater CAR-T cell expansion and prolonged persistence in a drug-dependent manner while providing a safety switch to mitigate toxicity concerns.

Regulated Expansion and Survival of Chimeric Antigen Receptor-Modified T Cells Using Small Molecule-Dependent Inducible MyD88/CD40.

Anti-tumor efficacy of T cells engineered to express chimeric antigen receptors (CARs) is dependent on their specificity, survival, and in vivo expansion following adoptive transfer. Toll-like receptor (TLR) and CD40 signaling in T cells can improve persistence and drive proliferation of antigen-specific CD4+ and CD8+ T cells following pathogen challenge or in graft-versus-host disease (GvHD) settings, suggesting that these costimulatory pathways may be co-opted to improve CAR-T cell persistence and function. Here, we present a novel strategy to activate TLR and CD40 signaling in human T cells using inducible MyD88/CD40 (iMC), which can be triggered in vivo via the synthetic dimerizing ligand, rimiducid, to provide potent costimulation to CAR-modified T cells. Importantly, the concurrent activation of iMC (with rimiducid) and CAR (by antigen recognition) is required for interleukin (IL)-2 production and robust CAR-T cell expansion and may provide a user-controlled mechanism to amplify CAR-T cell levels in vivo and augment anti-tumor efficacy.

Phase I trial of antigen-targeted autologous dendritic cell-based vaccine with in vivo activation of inducible CD40 for advanced prostate cancer.

This phase I trial reports the safety and activity of BPX101, a second-generation antigen-targeted autologous antigen presenting cell (APC) vaccine in men with metastatic castration-resistant prostate cancer (mCRPC). To manufacture BPX101, APCs collected in a single leukapheresis were transduced with adenoviral vector Ad5f35 encoding inducible human (ih)-CD40, followed by incubation with protein PA001, which contains the extracellular domain of human prostate-specific membrane antigen. The ih-CD40 represents a modified chimeric version of the dendritic cell (DC) co-stimulatory molecule, CD40, which responds to a bioinert membrane-permeable activating dimerizer drug, rimiducid (AP1903), permitting temporally controlled, lymphoid-localized, DC-specific activation. Eighteen men with progressive mCRPC following ≤1 prior chemotherapy regimen were enrolled to evaluate three doses of BPX101 (4 × 106, 12.5 × 106 and 25 × 106 cells) administered intradermally every 2-4 weeks followed by rimiducid (0.4 mg/kg) intravenous (IV) infusion 24 h after each BPX101 dose. There were no dose-limiting toxicities. Immune upregulation as well as anti-tumor activity was observed with PSA declines, objective tumor regressions and robust efficacy of post-trial therapy. This novel antigen-targeted and in vivo activated immunotherapy platform may warrant further development as monotherapy and as a component of rational combinations.

Prostate Health Index improves multivariable risk prediction of aggressive prostate cancer.

OBJECTIVE: To examine the use of the Prostate Health Index (PHI) as a continuous variable in multivariable risk assessment for aggressive prostate cancer in a large multicentre US study. MATERIALS AND METHODS: The study population included 728 men, with prostate-specific antigen (PSA) levels of 2-10 ng/mL and a negative digital rectal examination, enrolled in a prospective, multi-site early detection trial. The primary endpoint was aggressive prostate cancer, defined as biopsy Gleason score ≥7. First, we evaluated whether the addition of PHI improves the performance of currently available risk calculators (the Prostate Cancer Prevention Trial [PCPT] and European Randomised Study of Screening for Prostate Cancer [ERSPC] risk calculators). We also designed and internally validated a new PHI-based multivariable predictive model, and created a nomogram. RESULTS: Of 728 men undergoing biopsy, 118 (16.2%) had aggressive prostate cancer. The PHI predicted the risk of aggressive prostate cancer across the spectrum of values. Adding PHI significantly improved the predictive accuracy of the PCPT and ERSPC risk calculators for aggressive disease. A new model was created using age, previous biopsy, prostate volume, PSA and PHI, with an area under the curve of 0.746. The bootstrap-corrected model showed good calibration with observed risk for aggressive prostate cancer and had net benefit on decision-curve analysis. CONCLUSION: Using PHI as part of multivariable risk assessment leads to a significant improvement in the detection of aggressive prostate cancer, potentially reducing harms from unnecessary prostate biopsy and overdiagnosis.

MyD88/CD40 Genetic Adjuvant Function in Cutaneous Atypical Antigen-Presenting Cells Contributes to DNA Vaccine Immunogenicity.

Therapeutic DNA-based vaccines aim to prime an adaptive host immune response against tumor-associated antigens, eliminating cancer cells primarily through CD8+ cytotoxic T cell-mediated destruction. To be optimally effective, immunological adjuvants are required for the activation of tumor-specific CD8+ T cells responses by DNA vaccination. Here, we describe enhanced anti-tumor efficacy of an in vivo electroporation-delivered DNA vaccine by inclusion of a genetically encoded chimeric MyD88/CD40 (MC) adjuvant, which integrates both innate and adaptive immune signaling pathways. When incorporated into a DNA vaccine, signaling by the MC adjuvant increased antigen-specific CD8+ T cells and promoted elimination of pre-established tumors. Interestingly, MC-enhanced vaccine efficacy did not require direct-expression of either antigen or adjuvant by local antigen-presenting cells, but rather our data supports a key role for MC function in "atypical" antigen-presenting cells of skin. In particular, MC adjuvant-modified keratinocytes increased inflammatory cytokine secretion, upregulated surface MHC class I, and were able to increase in vitro and in vivo priming of antigen-specific CD8+ T cells. Furthermore, in the absence of critical CD8α+/CD103+ cross-priming dendritic cells, MC was still able to promote immune priming in vivo, albeit at a reduced level. Altogether, our data support a mechanism by which MC signaling activates an inflammatory phenotype in atypical antigen-presenting cells within the cutaneous vaccination site, leading to an enhanced CD8+ T cell response against DNA vaccine-encoded antigens, through both CD8α+/CD103+ dendritic cell-dependent and independent pathways.

The prostate health index selectively identifies clinically significant prostate cancer.

PURPOSE: The Prostate Health Index (phi) is a new test combining total, free and [-2]proPSA into a single score. It was recently approved by the FDA and is now commercially available in the U.S., Europe and Australia. We investigate whether phi improves specificity for detecting clinically significant prostate cancer and can help reduce prostate cancer over diagnosis. MATERIALS AND METHODS: From a multicenter prospective trial we identified 658 men age 50 years or older with prostate specific antigen 4 to 10 ng/ml and normal digital rectal examination who underwent prostate biopsy. In this population we compared the performance of prostate specific antigen, % free prostate specific antigen, [-2]proPSA and phi to predict biopsy results and, specifically, the presence of clinically significant prostate cancer using multiple criteria. RESULTS: The Prostate Health Index was significantly higher in men with Gleason 7 or greater and "Epstein significant" cancer. On receiver operating characteristic analysis phi had the highest AUC for overall prostate cancer (AUCs phi 0.708, percent free prostate specific antigen 0.648, [-2]proPSA 0.550 and prostate specific antigen 0.516), Gleason 7 or greater (AUCs phi 0.707, percent free prostate specific antigen 0.661, [-2]proPSA 0.558, prostate specific antigen 0.551) and significant prostate cancer (AUCs phi 0.698, percent free prostate specific antigen 0.654, [-2]proPSA 0.550, prostate specific antigen 0.549). At the 90% sensitivity cut point for phi (a score less than 28.6) 30.1% of patients could have been spared an unnecessary biopsy for benign disease or insignificant prostate cancer compared to 21.7% using percent free prostate specific antigen. CONCLUSIONS: The new phi test outperforms its individual components of total, free and [-2]proPSA for the identification of clinically significant prostate cancer. Phi may be useful as part of a multivariable approach to reduce prostate biopsies and over diagnosis.

Prospective multicenter evaluation of the Beckman Coulter Prostate Health Index using WHO calibration.

PURPOSE: Reported prostate specific antigen values may differ substantially among assays using Hybritech® or WHO standardization. The Beckman Coulter® Prostate Health Index and [-2]proPSA are newly approved serum markers associated with prostate cancer risk and aggressiveness. We studied the influence of assay standardization on these markers. MATERIALS AND METHODS: Prostate specific antigen, percent free prostate specific antigen and [-2]proPSA were measured using Hybritech calibration in 892 men from a prospective, multicenter study undergoing prostate biopsy. We calculated the Prostate Health Index using the equation, ([-2]proPSA/free prostate specific antigen) × PSA. Index performance characteristics for prostate cancer detection were then determined using recalculated WHO calibration prostate specific antigen values. RESULTS: The median Prostate Health Index was significantly higher in men with prostate cancer than in those with negative biopsies using WHO values (47.4 vs 39.8, p <0.001). The index offered improved discrimination of prostate cancer detection on biopsy (AUC 0.704) compared to percent free or total prostate specific antigen using the WHO calibration. CONCLUSIONS: The Prostate Health Index can be calculated using Hybritech or WHO standardized assays. It significantly improved prediction of the biopsy outcome over that of percent free or prostate specific antigen alone.

A composite MyD88/CD40 switch synergistically activates mouse and human dendritic cells for enhanced antitumor efficacy.

The in vivo therapeutic efficacy of DC-based cancer vaccines is limited by suboptimal DC maturation protocols. Although delivery of TLR adjuvants systemically boosts DC-based cancer vaccine efficacy, it could also increase toxicity. Here, we have engineered a drug-inducible, composite activation receptor for DCs (referred to herein as DC-CAR) comprising the TLR adaptor MyD88, the CD40 cytoplasmic region, and 2 ligand-binding FKBP12 domains. Administration of a lipid-permeant dimerizing ligand (AP1903) induced oligomerization and activation of this fusion protein, which we termed iMyD88/CD40. AP1903 administration to vaccinated mice enabled prolonged and targeted activation of iMyD88/CD40-modified DCs. Compared with conventionally matured DCs, AP1903-activated iMyD88/CD40-DCs had increased activation of proinflammatory MAPKs. AP1903-activated iMyD88/CD40-transduced human or mouse DCs also produced higher levels of Th1 cytokines, showed improved migration in vivo, and enhanced both antigen-specific CD8+ T cell responses and innate NK cell responses. Furthermore, treatment with AP1903 in vaccinated mice led to robust antitumor immunity against preestablished E.G7-OVA lymphomas and aggressive B16.F10 tumors. Thus, the iMyD88/CD40 unified "switch" effectively and safely replaced exogenous adjuvant cocktails, allowing remote and sustained DC activation in vivo. DC "licensing" through iMyD88/CD40 may represent a mechanism by which to exploit the natural synergy between the TLR and CD40 signaling pathways in DCs using a single small molecule drug and could augment the efficacy of antitumor DC-based vaccines.

The phosphatase SRC homology region 2 domain-containing phosphatase-1 is an intrinsic central regulator of dendritic cell function.

Dendritic cells (DCs) initiate proinflammatory or regulatory T cell responses, depending on their activation state. Despite extensive knowledge of DC-activating signals, the understanding of DC inhibitory signals is relatively limited. We show that Src homology region 2 domain-containing phosphatase-1 (SHP-1) is an important inhibitor of DC signaling, targeting multiple activation pathways. Downstream of TLR4, SHP-1 showed increased interaction with several proteins including IL-1R-associated kinase-4, and modulated LPS signaling by inhibiting NF-κB, AP-1, ERK, and JNK activity, while enhancing p38 activity. In addition, SHP-1 inhibited prosurvival signaling through AKT activation. Furthermore, SHP-1 inhibited CCR7 protein expression. Inhibiting SHP-1 in DCs enhanced proinflammatory cytokines, IL-6, IL-12, and IL-1ß production, promoted survival, and increased DC migration to draining lymph nodes. Administration of SHP-1-inhibited DCs in vivo induced expansion of Ag-specific cytotoxic T cells and inhibited Foxp3(+) regulatory T cell induction, resulting in an enhanced immune response against pre-established mouse melanoma and prostate tumors. Taken together, these data demonstrate that SHP-1 is an intrinsic global regulator of DC function, controlling many facets of T cell-mediated immune responses.

A multicenter study of [-2]pro-prostate specific antigen combined with prostate specific antigen and free prostate specific antigen for prostate cancer detection in the 2.0 to 10.0 ng/ml prostate specific antigen range.

PURPOSE: Prostate specific antigen and free prostate specific antigen have limited specificity to detect clinically significant, curable prostate cancer, leading to unnecessary biopsy, and detection and treatment of some indolent tumors. Specificity to detect clinically significant prostate cancer may be improved by [-2]pro-prostate specific antigen. We evaluated [-2]pro-prostate specific antigen, free prostate specific antigen and prostate specific antigen using the formula, ([-2]pro-prostate specific antigen/free prostate specific antigen × prostate specific antigen(1/2)) to enhance specificity to detect overall and high grade prostate cancer. MATERIALS AND METHODS: We enrolled 892 men with no history of prostate cancer, normal rectal examination, prostate specific antigen 2 to 10 ng/ml and 6-core or greater prostate biopsy in a prospective multi-institutional trial. We examined the relationship of serum prostate specific antigen, free-to-total prostate specific antigen and the prostate health index with biopsy results. Primary end points were specificity and AUC using the prostate health index to detect overall and Gleason 7 or greater prostate cancer on biopsy compared with those of free-to-total prostate specific antigen. RESULTS: In the 2 to 10 ng/ml prostate specific antigen range at 80% to 95% sensitivity the specificity and AUC (0.703) of the prostate health index exceeded those of prostate specific antigen and free-to-total prostate specific antigen. An increasing prostate health index was associated with a 4.7-fold increased risk of prostate cancer and a 1.61-fold increased risk of Gleason score greater than or equal to 4 + 3 = 7 disease on biopsy. The AUC of the index exceeded that of free-to-total prostate specific antigen (0.724 vs 0.670) to discriminate prostate cancer with Gleason 4 or greater + 3 from lower grade disease or negative biopsy. Prostate health index results were not associated with age and prostate volume. CONCLUSIONS: The prostate health index may be useful in prostate cancer screening to decrease unnecessary biopsy in men 50 years old or older with prostate specific antigen 2 to 10 ng/ml and negative digital rectal examination with minimal loss in sensitivity.

Emerging vaccine therapy approaches for prostate cancer.

Prostate cancer vaccines attempt to induce clinically relevant, cancer-specific systemic immune responses in patients with prostate cancer and represent a new class of targeted, nontoxic therapies. With a growing array of vaccine technologies in preclinical or clinical development, autologous antigen-presenting cell vaccines loaded with the antigen, prostate acid phosphatase, and poxvirus vaccines targeting prostate-specific antigen have recently demonstrated a significant survival benefit in randomized trials of patients with metastatic castration-resistant prostate cancer, whereas others have failed to demonstrate any benefit. The combination of vaccines with chemotherapy, radiotherapy, and other biologic agents is also being evaluated. Efforts to optimize vaccine approaches and select ideal patient populations need to continue to build on these early successes.

Pre-treatment biomarker levels improve the accuracy of post-prostatectomy nomogram for prediction of biochemical recurrence.

PURPOSE: We tested the ability of several pre-operative blood-based biomarkers to enhance the accuracy of standard post-operative features for the prediction of biochemical recurrence (BCR) after radical prostatectomy (RP). METHODS: Pre-operative plasma levels of Endoglin, interleukin-6 (IL-6), interleukin-6 soluble receptor (IL-6sR), transforming growth factor-beta1 (TGF-beta1), urokinase plasminogen activator (uPA), urokinase plasminogen inhibitor-1 (PAI-1), urokinase plasminogen receptor (uPAR), vascular cell adhesion molecule-1 (VCAM1), and vascular endothelial growth factor (VEGF) were measured using commercially available enzyme immunoassays in 423 consecutive patients treated with RP for clinically localized prostate cancer. Standard post-operative features consisted of surgical margin status, extracapsular extension, seminal vesicle invasion, lymph node involvement, and pathologic Gleason sum. Multivariable modeling was used to explore the gain in the predictive accuracy. The accuracy was quantified by the c-index statistic and was internally validated with 200 bootstrap resamples. RESULTS: Plasma IL-6 (P = 0.03), IL-6sR (P < 0.001), TGF-beta1 (P = 0.005), and V-CAM1 (P = 0.01) achieved independent predictor status after adjusting for the effects of standard post-operative features. After stepwise backward variable elimination, a model relying on RP Gleason sum, IL-6sR, TGF-beta1, VCAM1, and uPA improved the predictive accuracy of the standard post-operative model by 4% (86.1% vs. 82.1%, P < 0.001). CONCLUSIONS: Pre-operative plasma biomarkers improved the accuracy of established post-operative prognostic factors of BCR by a significant margin. Incorporation of these biomarkers into standard predictive models may allow more accurate identification of patients who are likely to fail RP thereby allowing more efficient delivery of adjuvant therapy.

A multi-institutional matched-control analysis of adjuvant and salvage postoperative radiation therapy for pT3-4N0 prostate cancer.

OBJECTIVES: It is unclear whether postoperative salvage radiation therapy (SRT) and early adjuvant radiotherapy (ART) after radical prostatectomy lead to equivalent long-term tumor control. We studied a group of patients undergoing ART by comparing them with a matched control group undergoing SRT after biochemical failure. METHODS: Using a multi-institutional database of 2299 patients, 449 patients with pT3-4N0 disease were eligible for inclusion, including 211 patients receiving ART and 238 patients receiving SRT. Patients were matched in a 1:1 ratio according to preoperative prostate-specific antigen Gleason score, seminal vesicle invasion, surgical margin status, and follow-up from date of surgery. RESULTS: A total of 192 patients were matched (96:96). The median follow-up was 94 months from surgery and 73 months from RT completion. There was a significant reduction in biochemical failure with ART compared with SRT. The 5-year freedom from biochemical failure (FFBF) from surgery was 75% after ART, compared with 66% for SRT (hazard ratio [HR] = 1.6, P = .049). The 5-year FFBF from the end of RT was 73% after ART, compared with 50% after SRT (HR = 2.3, log rank [LR] P = .0007). From the end of RT, SRT and Gleason score >or=8 were independent predictors of diminished FFBF. From the date of surgery, Gleason score >or=8 was a significant predictor of FFBF. CONCLUSIONS: Early ART for pT3-4N0 prostate cancer significantly reduces the risk of long-term biochemical progression after radical prostatectomy compared with SRT. Gleason score >or=8 was the only factor on multivariate analysis associated with metastasic progression.

Preoperative plasma endoglin levels predict biochemical progression after radical prostatectomy.

PURPOSE: Endoglin (CD105) is a transmembrane glycoprotein expressed by human vascular endothelial cells thought to play a pivotal role in endothelial cell proliferation. The aim of this study was to evaluate the association of preoperative plasma endoglin levels with established clinical and pathologic features of prostate cancer and disease progression after radical prostatectomy. EXPERIMENTAL DESIGN: Preoperative plasma endoglin levels were measured in 425 patients who underwent radical prostatectomy for clinically localized prostate cancer using a commercially available ELISA assay. Multivariate logistic regression was used to test the association of plasma endoglin levels with biochemical progression after radical prostatectomy. RESULTS: Median follow-up for patients alive at the time of analysis was 36.8 months (interquartile range, 44.1). Of 425 patients, 77 patients (18.1%) experienced biochemical progression after radical prostatectomy. Preoperative plasma endoglin levels were significantly elevated in patients with higher preoperative total serum prostate-specific antigen (P < 0.001) and adverse pathologic features. Preoperative plasma endoglin was an independent predictor of biochemical progression after surgery after adjusting for the effects of standard preoperative and postoperative features (P < 0.001 and P = 0.026, respectively). CONCLUSIONS: Preoperative plasma endoglin levels are associated with established features of advanced prostate cancer. More importantly, higher preoperative plasma endoglin levels are independent predictors of an increased risk of biochemical progression in patients treated with radical prostatectomy and bilateral pelvic lymphadenectomy.

Improved prediction of disease relapse after radical prostatectomy through a panel of preoperative blood-based biomarkers.

PURPOSE: The preoperative blood levels of biomarkers may allow accurate identification of patients who are likely to fail radical prostatectomy as a first-line therapy for localized prostate cancer, thereby allowing more efficient delivery of neoadjuvant and adjuvant therapy. The aim of this study was to determine the added value of biomarkers relative to established predictors of biochemical recurrence, such as clinical stage, biopsy Gleason sum, and preoperative prostate-specific antigen. EXPERIMENTAL DESIGN: The preoperative plasma levels of transforming growth factor-beta1 (TGF-beta1), interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), vascular endothelial growth factor (VEGF), vascular cell adhesion molecule-1 (VCAM-1), endoglin, urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1, and uPA receptor were measured with the use of commercially available enzyme immunoassays in 423 consecutive patients treated with radical prostatectomy and bilateral lymphadenectomy for clinically localized prostate cancer. Multivariable models were used to explore the gain in the predictive accuracy of the models. This predictive accuracy was quantified by the concordance index statistic and was validated with 200 bootstrap resamples. RESULTS: In standard multivariable analyses, TGF-beta1 (P < 0.001), sIL-6R (P < 0.001), IL-6 (P < 0.001), VCAM-1 (P < 0.001), VEGF (P = 0.008), endoglin (P = 0.002), and uPA (P < 0.001) were associated with biochemical recurrence. The multivariable model containing standard clinical variables alone had an accuracy of 71.6%. The addition of TGF-beta1, sIL-6R, IL-6, VCAM-1, VEGF, endoglin, and uPA increased the predictive accuracy by 15% to 86.6% (P < 0.001) and showed excellent calibration. CONCLUSIONS: A nomogram based on these biomarkers improves the accuracy of standard predictive models and could help counsel patients about their risk of biochemical recurrence following radical prostatectomy.

Use of preoperative plasma endoglin for prediction of lymph node metastasis in patients with clinically localized prostate cancer.

PURPOSE: Current predictive tools and imaging modalities are not accurate enough to preoperatively diagnose lymph node metastases in patients with prostate cancer. The aim of the study was to evaluate whether preoperative plasma endoglin improves the prediction of lymph node metastases in patients with clinically localized prostate cancer. EXPERIMENTAL DESIGN: Endoglin levels were measured using a commercially available ELISA assay in banked plasma from 425 patients treated with radical prostatectomy and bilateral lymphadenectomy for clinically localized prostatic adenocarcinoma at two university hospitals between July 1994 and November 1997. Logistic regression analyses were undertaken to evaluate whether endoglin improves the accuracy of a standard preoperative model for prediction of lymph node metastasis and to build a predictive nomogram. RESULTS: Preoperative plasma endoglin levels were higher in patients with higher preoperative total serum prostate-specific antigen (PSA; Spearman correlation coefficient 0.296, P < 0.001), positive surgical margins (P = 0.03), higher pathologic Gleason sum (P = 0.04), and lymph node metastasis (P < 0.001). In a preoperative multivariable logistic regression analysis that included PSA and clinical stage, only preoperative endoglin (odds ratio, 1.17; 95% confidence interval, 1.09-1.26; P < 0.001) and biopsy Gleason sum (odds ratio, 18.57; 95% confidence interval, 1.08-318.36; P = 0.04) were associated with metastasis to lymph nodes. The addition of endoglin to a standard preoperative model (including PSA, clinical stage, and biopsy Gleason sum) significantly improved its accuracy for prediction of lymph node metastasis from 89.4% to 97.8% (P < 0.001). CONCLUSIONS: Preoperative plasma endoglin improves the accuracy for prediction of pelvic lymph node metastasis in patients treated with radical prostatectomy for clinically localized prostate cancer by a statistically and clinically significant margin.