Antigen Density Research Articles

Is prostate-specific antigen density superior than prostate-specific antigen kinetics and prostate volume in predicting clinically insignificant prostate cancer?

Objectives: In this study, we aimed to evaluate the parameters that could predict clinically insignificant prostate cancer (ciPCa) in men who underwent transrectal ultrasound (TRUS)-guided prostate biopsy. Methods: Data of patients who underwent transrectal prostate biopsy between January 2015 and November 2019 were examined retrospectively. Free/total PSA ratio (fPSA%), serum total and free prostate-specific antigen (PSA) levels, prostate volumes (PV) measured by ultrasonography, and PSA density (PSAD) values of the patients before biopsy were recorded. ciPCa patients were defined as patients with Gleason scores ≤6 and clinical stage ≤T2a (Group 1). The remaining patients (Gleason score >6 and clinical stage >T2a) were included in Group 2 (clinical significant prostate cancer (csPCa). The parameters examined before biopsy were compared between groups. Results: After performing the exclusion criteria, the study counts in 168 patients with the current data of total/free PSA levels, age, PV calculated by TRUS, rectal examination findings, and pathology reports. Group 1 consisted of 115 patients and Group 2 consisted of 53 patients. In the univariate analysis, PV, total PSA and PSAD were found significantly different between groups, while age, free PSA, and fPSA% showed no significant difference between the two groups. According to the results of the multivariate analysis, the independent predictor of ciPCa was determined to be PSAD while total PSA and PV were not independent predictors. Conclusion: PSAD was found to be superior to other PSA kinetics in predicting ciPCa.

Enhancing bone metastasis prediction in prostate cancer using quantitative mpMRI features, ISUP grade and PSA density: a machine learning approach.

Bone metastasis is a critical complication in prostate cancer, significantly impacting patient prognosis and quality of life. This study aims to enhance bone metastasis prediction using machine learning (ML) techniques by integrating dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) perfusion features, International Society of Urological Pathology (ISUP) grade, and prostate-specific antigen (PSA) density. A retrospective analysis was conducted on 122 patients with histopathologically confirmed prostate cancer who underwent multiparametric prostate magnetic resonance imaging (mpMRI). Quantitative mpMRI features, PSA density, and ISUP grades were extracted and normalized. The dataset was balanced using oversampling and divided into training (70%) and test (30%) sets. Various ML models were developed and evaluated using area under the curve (AUC) metrics. Bone metastases were present in 26 patients (21.3%) at diagnosis. IAUGC and MaxSlope showed a statistically significant association with bone metastasis (p = 0.035, p = 0.050 respectively). The optimal PSA density cut-off value of 0.24 yielded a sensitivity of 0.88, specificity of 0.60, and AUC of 0.77. Machine learning models were developed using the dataset created with IAUGC, MaxSlope, ISUP grade, and PSA density values. Among the ML models, XGBoost demonstrated superior performance with validation and test AUCs of 91.5% and 92.6%, respectively, along with high precision (93.3%) and recall (93.1%). Integrating quantitative mpMRI features, ISUP grade, and PSA density through machine learning algorithms, particularly XGBoost, significantly improves the accuracy of bone metastasis prediction in prostate cancer patients. This approach can potentially reduce the need for additional imaging modalities and associated radiation exposure.

EXTH-03. CAR T-CELLS TARGETED TO B7-H3 OR HER2 FUNCTION INDEPENDENTLY OF ANTIGEN DENSITY IN XENOGRAFT MODELS OF EPENDYMOMA

Abstract BACKGROUND Targeted treatment options are desperately needed for ependymomas (EPN). Chimeric antigen receptor (CAR) T-cells have immense potential to positively transform treatment outcomes; however, little is known regarding antitumor efficacy of CAR T-cells against EPNs. Specifically, antigen density has emerged as a major influencer of CAR T-cell potency. However, the specific high and low antigen density thresholds governing CAR T-cell efficacy for EPN are unknown. The goal of this project is to determine the role of antigen density in CAR T-cell potency against EPN. METHODS Using quantitative flow cytometry, we determined antigen density of B7-H3 and HER2 (the two CAR targets currently in pediatric EPN clinical trials), on EPN patient derived cell lines (1425, ST1, CPITT, ST2, EPI, L46SJ). We generated B7-H3 and HER2-CAR T-cells with CD28z signaling domain and compared long-term cytolytic activity, expansion, and cytokine production against EPNs. RESULTS We found that all EPN cell lines express remarkably high yet variable density of B7-H3 (62,700 – 335,440 molecules/ cell). In contrast, surface density of HER2 was consistently and significantly lower (860 – 24,488 molecules/ cell). In repeated-stimulation assays, B7-H3-CAR T-cells killed 7-10 times and expanded up to 325,360-fold when cultured against EPN. However, we observed no significant difference in total expansion or correlation with antigen density against EPNs. Surprisingly, expansion of HER2-CAR T-cells against EPNs was drastically higher and greatly exceeded that of B7-H3-CAR-T cells against the same EPN cells despite much lower antigen density. CONCLUSIONS Our work shows that both B7-H3 and HER2 are good targets against EPN, despite drastic differences in antigen density. Results suggest that lower antigen density of HER2 may be superior for CAR T-cell activity. Future work will validate whether HER-CAR T-cells have superior antitumor efficacy in vivo to further delineate role of antigen density thresholds in CAR T-cell potency.

EXTH-02. MODIFYING CAR T CELL EPIGENETIC PROGRAMS TO IMPROVE THEIR PERSISTENCE AGAINST GROUP 3 MEDULLOBLASTOMAS

Abstract BACKGROUND Safe, effective therapies are desperately needed to improve outcomes for patients with medulloblastoma (MB), a malignant pediatric brain cancer. Chimeric antigen receptor (CAR)-T cells are a promising therapeutic option as they target T-cell cytotoxicity exclusively to tumor associated antigens. B7 homolog 3 (B7-H3) is an ideal target for CAR-T cell therapy as all MB subtypes express B7-H3 but healthy tissues do not. However, a major roadblock to tumor clearance and control is the inability of CAR-T cells to persist, suggesting that improving persistence will improve therapeutic efficacy. The goal of this study was to compare head-to-head the impact of knocking out TET2 and DNMT3A negative epigenetic regulators of CAR-T cell persistence against group 3 MB (G3MB), the most malignant MB subtype. METHODS We generated B7-H3 CAR-T cells with CD28ζ signaling domain and performed CRISPR/Cas9 knockout (KO) of TET2, DNMT3A, and AAVS1 as a control. We compared resulting CAR-T cell persistence via repeat stimulation assays in vitro against G3MB cell lines with varying B7-H3 antigen density (D341low, HDMB03mid, and D425high). We further compared KO CAR-T cells in vivo against D341low, HDMB03mid, and D425high orthotopic xenografts. RESULTS Our data shows that DNMT3A KO, but not TET2 KO, consistently improves the persistence and expansion of CAR-T cells against G3MB in vitro. In vivo, KO of epigenetic regulators, improves CAR-T cell therapy against highly aggressive D341low, HDMB03mid, and D425high but is insufficient to elicit curative responses. CONCLUSIONS Our study demonstrates that genetic KO of negative epigenetic regulators of CAR-T cell persistence can improve anti-tumor function against G3MB. We conclude that for the B7-H3.CD28ζ CAR, DNMT3A KO is superior for improving persistence over TET2 KO, but that DNMT3A KO is insufficient in vivo.

Digital Magnetic Sorting for Fractionating Cell Populations with Variable Antigen Expression in Cell Therapy Process Development

Cellular therapies exhibit immense potential in treating complex diseases with sustained responses. The manufacture of cell therapies involves the purification and engineering of specific cells from a donor or patient to achieve a therapeutic response upon injection. Magnetic cell sorting targeting the presence or absence of surface markers is commonly used for upfront purification. However, emerging research shows that optimal therapeutic phenotypes are characterized not only by the presence or absence of specific antigens but also by antigen density. Unfortunately, current cell purification tools like magnetic or fluorescence-activated cell sorting (FACS) lack the resolution to differentiate populations based on antigen density while maintaining scalability. Utilizing a technique known as digital magnetic sorting (DMS), we demonstrate proof of concept for a scalable, magnetic-based approach to fractionate cell populations based on antigen density level. Targeting CD4 on human leukocytes, DMS demonstrated fractionation into CD4Hi T cells and CD4Low monocytes and neutrophils as quantified by flow cytometry and single-cell RNA seq. DMS also demonstrated high throughput processing at throughputs 3–10× faster than FACS. We believe DMS can be leveraged and scaled to enable antigen density-based sorting in cell therapy manufacturing, leading to the production of more potent and sustainable cellular therapies.

The value of adjusted PSAD in prostate cancer detection in the Chinese population.

To investigate the value of adjusted prostate-specific antigen density (PSADadj) in the diagnosis of prostate cancer (PCa). Data from 410 patients who underwent transrectal ultrasound-guided prostate biopsy were retrospectively analyzed in Beijing Tsinghua Changgung Hospital between November 2014 and March 2024. All patients were divided into PCa and benign prostatic hyperplasia (BPH) groups according to pathological results. Multivariate logistic regression analyses were performed to evaluate the odd ratios (ORs) of predictors for PCa occurrence. Receiver operating characteristic curves were plotted, and the area under the curve (AUC) values were used to assess and compare the diagnostic accuracies of total PSA (tPSA), free-to-total (f/t) PSA, free PSA (fPSA), PSAD, and PSADadj (PSAD×weight). There were 166 patients in the PCa group and 244 in the BPH group. Multivariate analyses demonstrated that PSAD was positively correlated with the presence of PCa, with the highest OR value among all PSA-related parameters (OR = 19.075, p<0.001). tPSA, fPSAD, PSAD, and PSADadj had high accuracy in predicting PCa, with AUC values of 0.633, 0.730, 0.778, and 0.780. Of note, PSADadj had the highest AUC with a sensitivity of 63.3% and specificity of 81.6%. Similarly, in patients with a PSA level in the gray zone, the diagnostic accuracy of PSADadj in predicting PCa (AUC, 0.709; 95% CI, 0.616-0.802) remained better than other PSA-related markers. PSADadj has an advantage over other PSA-related markers in detecting PCa and could be used for making biopsy decisions.

Unlocking Precision Enhancing Prostate Cancer Detection and Reducing Unnecessary Biopsies with Combined Prostate-Specific Antigen Density and PI-RADS Score.

To determine clinically significant prostate cancer (csPCa) detection rate by combining the prostate-specific antigen density (PSAD) and prostate imaging-reporting and data system (PI-RADS) scores. Descriptive study. Place and Duration of the Study: Department of Urology, University of Health Sciences, Ankara Oncology Training and Research Hospital, from January 2018 to April 2023. Patients who underwent prostate biopsies after multiparametric magnetic resonance imaging (mpMRI) were included in the study. PI-RADS 4 and 5 lesions were considered as MR positive. The cut-off values for PSAD were also determined to evaluate csPCa. csPCa detection rates were evaluated by grouping the patients based on the PSAD and mpMRI findings. PSAD cut-off value of 0.165 ng/mL/mL (sensitivity 80%, specificity 72%) was detected to predict csPCa (AUC = 0.81, 95% CI:0.756-0.866, p<0.001). csPCa detection rate was low (3%) in patients who have low PI-RADS scores (1-3) and a PSAD <0.165 ng/mL/mL. On the other hand, csPCa detection rate was high (50.5%) in patients who have a high PI-RADS score (4-5 lesions) and with a PSAD ≥0.165 ng/mL/mL. csPCa detection rates are low in patients with PI-RADS 1-3 lesions and low PSAD values. Unnecessary biopsy may be avoided in these patients. Gleason score, PI-RADS, Prostate cancer, Prostate-specific antigen, Prostate-specific antigen density.

Determining Long-term Prostate Cancer Outcomes for Active Surveillance Patients Without Early Disease Progression: Implications for Slowing or Stopping Surveillance

Background and objectiveActive surveillance (AS) of prostate cancer (PCa) is the standard of care for low-grade disease, but there is limited guidance on tailoring protocols for stable patients. We investigated long-term outcomes for patients without initial progression and risk factors for upgrade. MethodsMen on AS with Gleason grade group (GG) 1 PCa on three serial biopsies, ≥5 yr without progression, and ≥10 yr of follow-up were included. Outcomes were upgrade (GG ≥2), major upgrade (GG ≥3), progression to treatment, metastasis, PCa-specific survival, and overall survival. Cox proportional hazards regression models were used to estimate the associations between patient characteristics and risk of upgrade. Key findings and limitationsA total of 774 men met the inclusion criteria. At 10, 12, and 15 yr, upgrade-free survival rates were 56%, 45%, and 21%; major upgrade–free survival rates were 88%, 83%, and 61%; treatment-free survival rates were 86%, 83%, and 73%; metastasis-free survival rates were 99%, 99%, and 98%; and overall survival rates were 98%, 96%, and 95%, respectively. PCa-specific survival was 100% at 15 yr. On a multivariable analysis, year of diagnosis, age, body mass index (BMI), and biopsy core positivity were associated with upgrade (all p < 0.01), whereas age and prostate-specific antigen (PSA) density were associated with major upgrade. Conclusions and clinical implicationsPatients without progression for 5 yr on AS had modest rates of upgrade and low rates of metastasis, and mortality at 15 yr of follow-up. Year of diagnosis, older age, increased BMI, and increased biopsy core positivity were associated with upgrade, whereas older age and greater PSA density were associated with an increased risk of major upgrade. A subset of these patients may benefit from deintensification of AS protocols. Patient summaryThere are little reported data or clinical guidelines for patients with prostate cancer (PCa) who are stable for many years on active surveillance (AS). We show, in a large cohort, that PCa patients without progression for 5 yr on AS have modest rates of upgrade and very low rates of metastasis, and mortality rates at 15 yr of follow-up, and that older age, increased body mass index, and increased PCa volume are associated with an increased likelihood of future upgrade. This study supports continued AS in this patient population and deintensification in select patients.

Impact of soluble BCMA and non–T-cell factors on refractoriness to BCMA targeting T-cell engagers in multiple myeloma

AbstractAdoptive T-cell therapy is a promising therapy for multiple myeloma (MM), but its efficacy hinges on understanding the relevant biologic and predictive markers of response. B-cell maturation antigen (BCMA) is a key target antigen in MM with active development of multiple anti-BCMA T-cell engagers (TCEs) and chimeric antigen receptor T-cell therapies. The regulation of surface BCMA expression by MM cells, which leads to shedding of soluble BCMA (sBCMA), has triggered debate about the significance of sBCMA as a predictive marker and its potential impact on treatment outcomes. To address this, we leveraged whole-genome sequencing and in vitro assays to demonstrate that sBCMA may independently predict primary refractoriness to anti-BCMA therapies. In addition to sBCMA, tumor burden and surface BCMA antigen density collectively influenced the anti-BCMA TCE cytotoxic efficacy. Correlative analyses of 163 patients treated with the anti-BCMA TCE teclistamab validated and further underscored the association between elevated baseline sBCMA (>400 ng/mL) and refractoriness. Importantly, increasing the TCE dose, using TCE against alternative targets (eg, GPRC5D), and gamma secretase inhibitors were able to overcome the high sBCMA levels. These findings highlight the importance of taking into account the baseline sBCMA levels, disease burden, and TCE dose intensity when administering anti-BCMA TCEs, thereby offering critical insights for optimizing therapeutic strategies to overcome specific high-risk features and primary anti-BCMA TCE refractoriness.

A CD38/CD3xCD28 trispecific T‐cell engager as a potentially active agent in multiple myeloma patients relapsed and/or refractory to anti‐CD38 monoclonal antibodies

SummaryThere is accumulating evidence of BCMA and GPRC5D loss after treatment with T‐cell redirecting therapies in patients with relapsed/refractory multiple myeloma (RRMM). While complete CD38 loss is not observed upon relapses after treatment with anti‐CD38 monoclonal antibodies (mAb), there is downregulation of surface CD38 expression and decreased number and function of NK cells, which renders these patients resistant to retreatment with anti‐CD38 mAb. Here, we provide preclinical evidence that RRMM patients previously exposed to anti‐CD38 mAb could benefit from T‐cell‐based immunotherapy that depend less on CD38 antigen density and NK‐cell activity, such as the novel CD38/CD3xCD28 trispecific T‐cell engager, SAR442257.

Determinants of decision-making in biopsy of PI-RADS 3 transition zone lesions.

Cancer rates for Prostate Imaging-Reporting and Data System (PI-RADS) 3 lesions are low. We aimed to determine the clinical and magnetic resonance imaging (MRI) parameters that can provide risk stratification for PI-RADS 3 transition zone (TZ) lesions to guide decision for biopsy, which can improve the cost-effectiveness of resource utilisation. The MRI scans of all patients who underwent MRI-ultrasound fusion targeted biopsy from 1 May 2016 to 31 December 2022 were retrospectively assessed by two board-certified abdominal radiologists. The following data were collected and analysed serum prostate-specific antigen, Prostatic Health Index (PHI), prostate volume, histological results, lesion size, location, diffusion-weighted imaging (DWI) parameter scores and overall PI-RADS score. Two hundred and fourteen TZ lesions were included. Among 131 PI-RADS 3 lesions, those with marked restricted diffusion (DWI score ≥4), diameter ≥1 cm, prostrate-specific antigen density (PSAD) ≥0.11 and PHI ≥34 were more likely to contain clinically significant prostate cancer (csPCa; P = 0.04, 0.02, 0.049 and 0.05, respectively), with areas under the receiver operating characteristics curve of 0.9, 0.76, 0.84 and 0.80, respectively. Apical lesions were more likely to contain csPCa compared to midgland or basal lesions (P = 0.01). Clinical parameters (PSAD and PHI) and MRI features (lesion size, DWI score, lesion location) can be used to risk stratify PI-RADS 3 TZ lesions and guide decision for targeted biopsy.

Natural TCRs targeting KRASG12V display fine specificity and sensitivity to human solid tumors.

BACKGROUNDNeoantigens derived from KRASMUT have been described, but the fine antigen specificity of T cell responses directed against these epitopes is poorly understood. Here, we explore KRASMUT immunogenicity and the properties of 4 T cell receptors (TCRs) specific for KRASG12V restricted to the HLA-A3 superfamily of class I alleles.METHODSA phase 1 clinical vaccine trial targeting KRASMUT was conducted. TCRs targeting KRASG12V restricted to HLA-A*03:01 or HLA-A*11:01 were isolated from vaccinated patients or healthy individuals. A comprehensive analysis of TCR antigen specificity, affinity, crossreactivity, and CD8 coreceptor dependence was performed. TCR lytic activity was evaluated, and target antigen density was determined by quantitative immunopeptidomics.RESULTSVaccination against KRASMUT resulted in the priming of CD8+ and CD4+ T cell responses. KRASG12V -specific natural (not affinity enhanced) TCRs exhibited exquisite specificity to mutated protein with no discernible reactivity against KRASWT. TCR-recognition motifs were determined and used to identify and exclude crossreactivity to noncognate peptides derived from the human proteome. Both HLA-A*03:01 and HLA-A*11:01-restricted TCR-redirected CD8+ T cells exhibited potent lytic activity against KRASG12V cancers, while only HLA-A*11:01-restricted TCR-T CD4+ T cells exhibited antitumor effector functions consistent with partial coreceptor dependence. All KRASG12V-specific TCRs displayed high sensitivity for antigen as demonstrated by their ability to eliminate tumor cell lines expressing low levels of peptide/HLA (4.4 to 242) complexes per cell.CONCLUSIONThis study identifies KRASG12V-specific TCRs with high therapeutic potential for the development of TCR-T cell therapies.TRIAL REGISTRATIONClinicalTrials.gov NCT03592888.FUNDINGAACR SU2C/Lustgarten Foundation, Parker Institute for Cancer Immunotherapy, and NIH.

Expansion of tumor-reactive CD8+ T cell clonotypes occurs in the spleen in response to immune checkpoint blockade.

Immune checkpoint blockade (ICB) enhances T cell responses against cancer, leading to long-term survival in a fraction of patients. CD8+ T cell differentiation in response to chronic antigen stimulation is highly complex, and it remains unclear precisely which T cell differentiation states at which anatomic sites are critical for the response to ICB. We identified an intermediate-exhausted population in the white pulp of the spleen that underwent substantial expansion in response to ICB and gave rise to tumor-infiltrating clonotypes. Increased systemic antigen redirected differentiation of this population toward a more circulatory exhausted KLR state, whereas a lack of cross-presented tumor antigen reduced its differentiation in the spleen. An analogous population of exhausted KLR CD8+ T cells in human blood samples exhibited diminished tumor-trafficking ability. Collectively, our data demonstrate the critical role of antigen density within the spleen for the differentiation and expansion of T cell clonotypes in response to ICB.

Predicting clinically significant prostate cancer in elderly patients: A nomogram approach with shear wave elastography.

This study was to construct a nomogram utilizing shear wave elastography and assess its efficacy in detecting clinically significant prostate cancer (csPCa). 290 elderly people with suspected PCa who received prostate biopsy and shear wave elastography (SWE) imaging were respectively registered from April 2022 to December 2023. The elderly participants were stratified into two groups: those with csPCa and those without csPCa, which encompassed cases of clinically insignificant prostate cancer (cisPCa) and non-prostate cancer tissue, as determined by pathology findings. The LASSO algorithm, known as the least absolute shrinkage and selection operator, was utilized to identify features. Logistic regression analysis was utilized to establish models. Receiver operating characteristic (ROC) and calibration curves were utilized to evaluate the discriminatory ability of the nomogram. Bootstrap (1000 bootstrap iterations) was employed for internal validation and comparison with two models. A decision curve and a clinical impact curve were employed to assess the clinical usefulness. Our nomogram, which contained Emean, ΔEmean, prostate volume, prostate-specific antigen density (PSAD), and transrectal ultrasound (TRUS), showed better discrimination (AUC = 0.89; 95% CI: 0.83-0.94), compared to the clinical model without SWE parameters (p = 0.0007). Its accuracy, sensitivity and specificity were 0.83, 0.89 and 0.78, respectively. Based on the analysis of decision curve, the thresholds ranged from 5% to 90%. According to our nomogram, biopsying patients at a 20% probability threshold resulted in a 25% reduction in biopsies without missing any csPCa. The clinical impact curve demonstrated that the nomogram's predicted outcome is closer to the observed outcome when the probability threshold reaches 20% or greater. Our nomogram demonstrates efficacy in identifying elderly individuals with clinically significant prostate cancer, thereby facilitating informed clinical decision-making based on diagnostic outcomes and potential clinical benefits.

Consistent predictive ability of prostate-specific antigen density prediction model for clinically significant prostate cancer across age strata.

Prebiopsy prostate-specific antigen density (PSAD) is a well-known predictor of clinically significant prostate cancer (csPCa). Since prostate-specific antigen(PSA) and prostate volume (PV) increase normally with aging, PSAD thresholds may vary. The purpose of the study was to determine if PSAD was predictive of csPCa in different age strata. We retrospectively reviewed our institutional database for patients who underwent multiparametricmagnetic resonance imaging (MRI) between January 2016 and December 2021. We included patients who had post-MRI prostate biopsies. Based on age, we divided our cohort into four subgroups (groups 1-4): <55, 55-64, 65-74, and ≥75 years old. PSAD accuracy was estimated by the area under the curve (AUC) as a predictive model for differentiating csPCa between the groups. CsPCa was defined as a Gleason Grade Group 2 or higher. Three different PSAD thresholds (0.1, 0.15, and 0.2) were tested across the groups for sensitivity, specificity, and positive predictive value (PPV) and negative predictive value(NPV). Chi-square and analysis of variance tests were used for bivariate analysis. All analyswere completed using R 4.3 (R Core Team, 2023). Among 1913 patients, 883 (46.1%) had prostate biopsies. In groups 1, 2, 3, and 4, there were 62 (7%), 321 (36.4%), 404 (45.8%), and 96 (10.9%) patients, respectively. Median PSA was 5.6 (interquartile range 3.4-8.1), 6.2 (4.8-9), 6.8 (5.1-9.7), and 9 (5.6-13), respectively (p < 0.01). Median PV was 42.3 (30-62), 51 (36-77), 55.5 (38-85.9), and 59.3 (42-110) mL, respectively (p < 0.01). No difference was observed in median PSAD between age groups 1-4 (0.1 [0.07-0.16], 0.11 [0.08-0.18], 0.1 [0.07-0.19], and 0.1 [0.07-0.2]), respectively (p = 0.393). CsPCa was diagnosed in 241 (27.3%) patients, of which 10 (16.1%), 65 (20.2%), 121 (30%), and 45 (46.7%) were in groups 1-4, respectively (p < 0.001). For groups 1-4, the PSAD AUC for predicting csPCa was 0.75, 0.68, 0.71, and 0.74. While testing PSAD threshold of 0.15 across the different age groups (1-4), the PPV vs.NPV was 39.1 vs. 93.2, 33.6 vs. 87, 50.9 vs. 80.8, and 66.1 vs. 64.7, respectively. PSAD prediction model was found to be similar among different age groups. In young patients, PSAD had a high NPV but low PPV. With increasing age, the opposite trend was observed, likely due to higher disease prevalence. While PSAD thresholds may be less useful in older patients to rule out higher-grade prostate cancer, the clinical consequences of these diagnoses require a case-by-case evaluation.

Detection of TurboID fusion proteins by fluorescent streptavidin outcompetes antibody signals and visualises targets not accessible to antibodies.

Immunofluorescence localises proteins via fluorophore-labelled antibodies. However, some proteins evade detection due to antibody-accessibility issues or because they are naturally low abundant or antigen density is reduced by the imaging method. Here, we show that the fusion of the target protein to the biotin ligase TurboID and subsequent detection of biotinylation by fluorescent streptavidin offers an 'all in one' solution to these restrictions. For all proteins tested, the streptavidin signal was significantly stronger than an antibody signal, markedly improving the sensitivity of expansion microscopy and correlative light and electron microscopy. Importantly, proteins within phase-separated regions, such as the central channel of the nuclear pores, the nucleolus, or RNA granules, were readily detected with streptavidin, while most antibodies failed. When TurboID is used in tandem with an HA epitope tag, co-probing with streptavidin and anti-HA can map antibody-accessibility and we created such a map for the trypanosome nuclear pore. Lastly, we show that streptavidin imaging resolves dynamic, temporally, and spatially distinct sub-complexes and, in specific cases, reveals a history of dynamic protein interaction. In conclusion, streptavidin imaging has major advantages for the detection of lowly abundant or inaccessible proteins and in addition, provides information on protein interactions and biophysical environment.

Analysis of risk factors for persistent PSA after radical prostatectomy: results from a high-volume center in Southeast China

BackgroundFor localized prostate cancer, a comprehensive treatment approach centered around radical prostatectomy (RP) is often their optimal choice. Successful RP can typically reduce prostate-specific antigen (PSA) levels to below 0.1 ng/mL within 6 to 8 weeks postoperatively. However, in clinical practice, 5 to 24% of patients may have a PSA ≥ 0.1 ng/mL at 6 to 8 weeks after surgery, a phenomenon known as PSA persistence. Many studies based on data from Europe and United States have shown an association between PSA persistence and poor postoperative outcomes, further analyzing the risk factors for PSA persistence. However, relevant research based on data from China remains scarce.MethodsRetrospective study of 1,347 prostate cancer patients who underwent RP at the First Affiliated Hospital of Zhejiang University School of Medicine from July 15, 2016, to August 31, 2022. Based on inclusion criteria, univariate and multivariate logistic regression analyses were conducted to explore the independent risk factors for persistent PSA.ResultsAmong the 826 prostate cancer patients after RP, 124 patients experienced persistent PSA. In univariate logistic regression analysis, robot-assisted laparoscopic radical prostatectomy (RARP), preoperative PSA, high-risk group, preoperative International Society of Urological Pathology (ISUP) grades 2–5, postoperative ISUP grades 3–5, percentage of positive cores, cT3, ≥pT3b, extracapsular extension (EPE), seminal vesicle invasion (SVI), positive surgical margins (PSM) and Prostate Specific Antigen Density (PSAD) were all significantly associated with PSA persistence after RP (P < 0.05). In terms of surgical approach, RARP was considered a protective factor against postoperative PSA persistence (OR:0.53, p < 0.05). In multivariate logistic regression analysis, preoperative ISUP grade 4, percentage of positive cores and PSM were independent risk factors of PSA persistence after RP (P < 0.05).ConclusionPreoperative PSA, high-risk group, preoperative ISUP grades 2–5, postoperative ISUP grades 3–5, percentage of positive cores, cT3, ≥pT3b, EPE, SVI, PSM and PSAD were independent risk factors for PSA persistence in prostate cancer patients after RP. This provides assistance for early monitoring and treatment of patients at high risk of persistent PSA in clinical practice.

Development and validation of a novel nomogram to avoid unnecessary biopsy in patients with PI-RADS category ≥ 4 lesions and PSA ≤ 20 ng/ml.

To develop and validate a prediction model for identifying non-prostate cancer (non-PCa) in biopsy-naive patients with PI-RADS category ≥ 4 lesions and PSA ≤ 20 ng/ml to avoid unnecessary biopsy. Eligible patients who underwent transperineal biopsies at West China Hospital between 2018 and 2022 were included. The patients were randomly divided into training cohort (70%) and validation cohort (30%). Logistic regression was used to screen for independent predictors of non-PCa, and a nomogram was constructed based on the regression coefficients. The discrimination and calibration were assessed by the C-index and calibration plots, respectively. Decision curve analysis (DCA) and clinical impact curves (CIC) were applied to measure the clinical net benefit. A total of 1580 patients were included, with 634 non-PCa. Age, prostate volume, prostate-specific antigen density (PSAD), apparent diffusion coefficient (ADC) and lesion zone were independent predictors incorporated into the optimal prediction model, and a corresponding nomogram was constructed ( https://nomogramscu.shinyapps.io/PI-RADS-4-5/ ). The model achieved a C-index of 0.931 (95% CI, 0.910-0.953) in the validation cohort. The DCA and CIC demonstrated an increased net benefit over a wide range of threshold probabilities. At biopsy-free thresholds of 60%, 70%, and 80%, the nomogram was able to avoid 74.0%, 65.8%, and 55.6% of unnecessary biopsies against 9.0%, 5.0%, and 3.6% of missed PCa (or 35.9%, 30.2% and 25.1% of foregone biopsies, respectively). The developed nomogram has favorable predictive capability and clinical utility can help identify non-PCa to support clinical decision-making and reduce unnecessary prostate biopsies.

Afucosylated broadly neutralizing antibodies enhance clearance of HIV-1 infected cells through cell-mediated killing

Broadly neutralizing antibodies (bNAbs) targeting the HIV-1 envelope glycoprotein (Env) have the capacity to delay viral rebound when administered to people with HIV-1 (PWH) during anti-retroviral therapy (ART) interruption. To further enhance the performance of bNAbs through their Fc effector functions, in particular NK cell-mediated killing of HIV-1 infected cells, we have produced a panel of glyco-engineered (afucosylated) bNAbs with enhanced affinity for Fc gamma receptor IIIa. These afucosylated anti-HIV-1 bNAbs enhance NK cell activation and degranulation compared to fucosylated counterparts even at low antigen density. NK cells from PWH expressing exhaustion markers PD-1 and TIGIT are activated in a similar fashion by afucosylated bNAbs as NK cell from HIV-1 negative individuals. Killing of HIV-1 infected cells is most effective with afucosylated bNAbs 2G12, N6, PGT151 and PGDM1400, whereas afucosylated PGT121 and non-neutralizing antibody A32 only induce minor NK cell-mediated killing. These data indicate that the approach angle and affinity of Abs influence the capacity to induce antibody-dependent cellular cytotoxicity. Thus, afucosylated bNAbs have the capacity to induce NK cell-mediated killing of infected cells, which warrants further investigation of afucosylated bNAb administration in vivo, aiming for reduction of the viral reservoir and ART free durable control.

Precision in prostate cancer detection: integrating prostate-specific antigen density (PSAD) and the Prostate Imaging Reporting and Data System (PI-RADS) to provide additional risk stratification for a more accurate diagnostic decision.

This study focuses on integrating prostate-specific antigen density (PSAD) and Prostate Imaging Reporting and Data System (PI-RADS) for enhanced risk stratification in biopsy-naïve patients. A prospective study was conducted on 339 patients with suspected prostate cancer, utilizing PSAD and PI-RADS in combination. Logistic regression models were employed, and receiver operating characteristic (ROC) analysis performed to evaluate predictive performance. The patient cohort underwent multiparametric MRI, targeted biopsy, and systematic biopsy. When patients were stratified into four PSAD risk groups, the rate of clinically significant prostate cancer (csPCa) increased significantly with higher PSAD levels. Logistic regression confirmed the independent contribution of PI-RADS and PSAD, highlighting their role in the prediction of csPCa. Combined models showed superior performance, as evidenced by the area under the curve (AUC) for PI-RADS category and PSAD (0.756), which exceeded that of the individual predictors (PSA AUC, 0.627, PI-RADS AUC 0.689, PSAD AUC 0.708). This study concludes that combining PSAD and PI-RADS improves diagnostic accuracy and predictive value for csPCa in biopsy-naïve men, resulting in a promising strategy to provide additional risk stratification for more accurate diagnostic decision in biopsy-naïve patients, especially in the PI-RADS 3 group.