Nomogram to predict the presence of PSMA-negative but FDG-positive lesion in castration-resistant prostate cancer: a multicenter cohort study

Background

PSMA-negative but FDG-positive (PSMA-/FDG+) lesion in dual-tracer (68Ga-PSMA and 18F-FDG) positron emission tomography/computed tomography (PET/CT) is associated with an unfavorable response to Lutetium-177 (177Lu)-PSMA-617. This study sought to develop both radiomics and clinical models for the precise prediction of the presence of PSMA-/FDG+ lesions in patients with castration-resistant prostate cancer (CPRC).

Methods

A cohort of 298 patients who underwent dual-tracer PET/CT with a less than 5-day interval was included. The evaluation of the prognostic performance of the radiomics model drew upon the survival data derived from 40 patients with CRPC treated with 177Lu-PSMA-617 in an external cohort. Two endpoints were evaluated: (a) prostate-specific antigen (PSA) response rate, defined as a reduction exceeding 50% from baseline and (b) overall survival (OS), measured from the initiation of 177Lu-PSMA-617 to death from any cause.

Results

PSMA-/FDG+ lesions were identified in 56 (18.8%) CRPC patients. Both radiomics (area under the curve [AUC], 0.83) and clinical models (AUC, 0.78) demonstrated robust performance in PSMA-/FDG+ lesion prediction. Decision curve analysis revealed that the radiomics model yielded a net benefit over the 'screen all' strategy at a threshold probability of ⩾4%. At a 5% probability threshold, the radiomics model facilitated a 21% reduction in 18F-FDG PET/CT scans while only missing 2% of PSMA-/FDG+ cases. Patients with a low estimated score exhibited significantly prolonged OS (hazard ratio = 0.49, p = 0.029) and a higher PSA response rate (75% versus 35%, p = 0.011) compared to those with a high estimated score.

Conclusion

This study successfully developed two models with accurate estimations of the risk associated with PSMA-/FDG+ lesions in CRPC patients. These models held potential utility in aiding the selection of candidates for 177Lu-PSMA-617 treatment and guiding 68Ga-PSMA PET/CT-directed radiotherapy.

Single-cell RNA-seq analysis decodes the kidney microenvironment induced by polystyrene microplastics in mice receiving a high-fat diet

In recent years, the environmental health issue of microplastics has aroused an increasingly significant concern. Some studies suggested that exposure to polystyrene microplastics (PS-MPs) may lead to renal inflammation and oxidative stress in animals. However, little is known about the essential effects of PS-MPs with high-fat diet (HFD) on renal development and microenvironment. In this study, we provided the single-cell transcriptomic landscape of the kidney microenvironment induced by PS-MPs and HFD in mouse models by unbiased single-cell RNA sequencing (scRNA-seq). The kidney injury cell atlases in mice were evaluated after continued PS-MPs exposure, or HFD treated for 35 days. Results showed that PS-MPs plus HFD treatment aggravated the kidney injury and profibrotic microenvironment, reshaping mouse kidney cellular components. First, we found that PS-MPs plus HFD treatment acted on extracellular matrix organization of renal epithelial cells, specifically the proximal and distal convoluted tubule cells, to inhibit renal development and induce ROS-driven carcinogenesis. Second, PS-MPs plus HFD treatment induced activated PI3K-Akt, MAPK, and IL-17 signaling pathways in endothelial cells. Besides, PS-MPs plus HFD treatment markedly increased the proportions of CD8+ effector T cells and proliferating T cells. Notably, mononuclear phagocytes exhibited substantial remodeling and enriched in oxidative phosphorylation and chemical carcinogenesis pathways after PS-MPs plus HFD treatment, typified by alterations tissue-resident M2-like PF4+ macrophages. Multispectral immunofluorescence and immunohistochemistry identified PF4+ macrophages in clear cell renal cell carcinoma (ccRCC) and adjacent normal tissues, indicating that activate PF4+ macrophages might regulate the profibrotic and pro-tumorigenic microenvironment after renal injury. In conclusion, this study first systematically revealed molecular variation of renal cells and immune cells in mice kidney microenvironment induced by PS-MPs and HFD with the scRNA-seq approach, which provided a molecular basis for decoding the effects of PS-MPs on genitourinary injury and understanding their potential profibrotic and carcinogenesis in mammals.

Heterogeneity in tertiary lymphoid structures predicts distinct prognosis and immune microenvironment of clear cell renal cell carcinoma

BACKGROUND

Tertiary lymphoid structures (TLS) are organized aggregates of immune cells that develop postnatally in non-lymphoid tissues and are associated with pathological conditions. TLS typically comprise B-cell follicles containing and are encompassed by T- cell zones and dendritic cells. The prognostic and predictive value of TLS in the tumor microenvironment (TME) as potential mediators of antitumor immunity have gained interest. However, the precise relationship between localization and maturation of TLS and the clinical outcome of their presence in clear cell renal cell carcinoma (ccRCC) is yet to be elucidated.

METHODS

Immunohistochemistry and multispectral fluorescence were used to evaluate the TLS heterogeneity along with TME cell-infiltrating characterizations. A thorough investigation of the prognostic implications of the TLS heterogeneity in 395 patients with ccRCC from two independent cohorts was conducted. Associations between TLS heterogeneity and immunologic activity were assessed by quantifying the immune cell infiltration.

RESULTS

Infiltrated TLS were identified in 34.2% of the ccRCC samples (N=395). These TLS were found to be tumor-proximal, tumor-distal, or both in 37.8%, 74.1%, and 11.9% of the TLS-positive cases, respectively. A higher proportion of early TLS was found in tumor-distal TLS (p=0.016), while tumor-proximal TLS primarily comprised secondary follicle-like structures (p=0.004). In the main study cohort (Fudan University Shanghai Cancer Center, N=290), Kaplan-Meier analyses revealed a significant correlation between the presence of tumor-proximal TLS and improved progression-free survival (PFS, p<0.001) and overall survival (OS, p=0.002). Conversely, the presence of tumor-distal TLS was associated with poor PFS (p=0.02) and OS (p=0.021). These findings were further validated in an external validation set of 105 patients with ccRCC. Notably, the presence of mature TLS (namely secondary follicle-like TLS, with CD23+ germinal center) was significantly associated with better clinical outcomes in patients with ccRCC. Furthermore, novel nomograms incorporating the presence of tumor-proximal TLS demonstrated remarkable predictability for the 8-year outcomes of resected ccRCC (area under the curve >0.80). Additionally, ccRCC samples with tumor-distal TLS enriched with primary follicle-like TLS exhibited higher programmed death-ligand 1 tumor-associated macrophages levels and regulatory T cells infiltration in the tumor-distal region, indicative of a suppressive TME.

CONCLUSION

This study for the first time elucidates the impact of TLS localization and maturation heterogeneities on the divergent clinical outcomes of ccRCC. The findings reveal that most TLS in ccRCC are located in the tumor-distal area and are associated with immature, immunosuppressive characterizations. Furthermore, our findings corroborate previous research demonstrating that tumor-proximal TLS were associated with favorable clinical outcomes.

Heterogeneity of [68Ga]Ga-PSMA-11 PET/CT in metastatic castration-resistant prostate cancer: genomic characteristics and association with abiraterone response

PURPOSE

The aim of this study was to evaluate the impact of the spatial heterogeneity of prostate-specific membrane antigen (PSMA) uptake on circulating tumor DNA (ctDNA) characteristics and the response rate to new hormonal agent (NHA) treatment.

METHODS

This retrospective study included 153 patients with metastatic castration-resistant prostate cancer (mCRPC) who underwent gallium-68 [68 Ga]Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) and ctDNA sequencing with a less than 2-week interval. SUVhetero was defined as the variance of SUVmean for each PSMA-positive lesion. SUVmax-mean was obtained by subtracting the SUVmax by the SUVmean. Patients receiving abiraterone treatment after [68 Ga]Ga-PSMA-11 PET/CT and ctDNA sequencing and with complete follow-up record were included into prostate-specific antigen (PSA) response rate analysis. PSA response was defined as a reduction of greater than 50% from baseline.

RESULTS

The ctDNA detection rate was 65% (100/153). Higher SUVhetero value contributed to higher ctDNA% (Spearman's rho = 0.278, p < 0.002). A total of 60 patients were included in PSA response rate analysis. The median follow-up was 19.3 (IQR 16.2-23.2) months. Compare to patients with higher SUVhetero value, patients with NA SUVhetero had a higher PSA response rate (52% vs. 90%, p = 0.036). A higher SUVmax-mean value was strongly correlated with higher SUVhetero (Spearman's rho = 0.833, p < 0.0001). Patients with higher SUVmax-mean value also had a higher PSA response rate compared to patients with lower SUVmax-mean value (83.3% vs. 53.3%, p = 0.024). An external cohort confirmed baseline SUVmax-mean value was associated with enzalutamide treatment response rate. Patients with alterations in AR, DNA damage repair pathway, TP53, AR-associated pathway, cell cycle pathway, or WNT pathway had higher SUVmax-mean value compared to those without (p < 0.05).

CONCLUSION

Spatial heterogeneity of the PSMA uptake was associated with ctDNA characteristics and response rate to NHA treatment.