Motohide Uemura

Background: Although immunosuppressive factors contribute to the recurrence of non-muscle invasive bladder cancer (NMIBC) during Bacillus Calmette–Guérin (BCG) therapy, the mechanism remains unclear. Methods: In this study, key players in the immunosuppression associated with recurrence after BCG therapy were identified through comprehensive genetic and functional analyses of untreated NMIBC. Results: Microarray analysis of bladder cancer tissue from 13 eligible NMIBC patients revealed an association between high expression of integrin β8 (ITGB8) and recurrence after BCG treatment (p < 0.001). In UMUC cells exhibiting high ITGB8 expression, ITGB8 knockdown significantly decreased cell growth, invasion, adhesion, and secretion of the immunosuppressive cytokine transforming growth factor-β1 (TGF-β1, p < 0.01 for each). In addition, ITGB8 and TGF-β1 expression were correlated in immunohistochemistry of surgical specimens from 13 patients (p < 0.05). These results indicate that ITGB8 regulates TGF-β1 secretion. Conclusions: ITGB8 may contribute to post-BCG therapy recurrence of NMIBC by suppressing tumor immunity through the activation of TGF-β1. Evaluation of ITGB8 expression in preoperative NMIBC could potentially predict recurrence following intravesical BCG therapy.

Since cancer is often linked to the aging process, the importance of cellular senescence in cancer has come under the spotlight. While senescence in cancer cells can serve as a natural barrier against cancer due to its proliferation arrest, its secretory phenotypes and alterations in the surface proteome can paradoxically promote or suppress tumor progression. Senescent cancer-associated fibroblasts, endothelial cells, and immune cells can also contribute to cancer promotion. During therapeutic interventions for cancer, not only their therapeutic effects, but also therapy-induced senescence may have an impact on cancer outcomes. Senotherapeutics, therapy targeting senescent cells, have been reported as novel cancer therapy in recent studies, and the combination of senescence induction and senotherapeutics has been increasingly recognized. Although some clinical trials of senotherapeutic drugs for cancer with or without senescence-inducible therapy are ongoing, there is as yet no satisfactory clinical application. With further research into targeting senescence in oncology, it is expected that senotherapeutics, particularly in combination with senescence-inducing therapy, will become a novel therapeutic strategy.

Therapeutic strategies for advanced renal cell carcinoma have advanced dramatically since the approval of immune checkpoint inhibitors. To date, four PD-L1 assays have been established as companion diagnostic tools for checkpoint inhibitors. However, all PD-L1 assays present several limitations in terms of concordance and compatibility. In this study, we constructed tissue microarrays from 286 clear cell renal cell carcinoma (ccRCC) tissue samples and evaluated PD-L1 expression using the 22C3, 28 - 8, SP142, and SP263 PD-L1 assays. Detection of PD-L1 expression in tumor cells was very low for all PD-L1 assays tested, although expression of PD-L1 in immune cells in the tumor area was 14.7% for 22C3, 16.1% for 28 - 8, 2.1% for SP142, and 15.0% for SP263. PD-L1 expression on immune cells assessed by 28 - 8 showed a moderate pairwise concordance with other assays (κ statistics: 0.52 with 22C3, 0.16 with SP142, and 0.46 with SP263). Patients with PD-L1 expression in immune cells evaluated using 22C3, 28 - 8, and SP263 showed significantly worse cancer-specific survival. PD-L1 expression on renal cell carcinoma tissues assessed using 22C3, 28 - 8, SP142, and SP263 did not show good concordance. In conclusion, differences between these assays should be considered when evaluating the results of immunohistochemical findings.

Background: Despite the high recurrence rate of non‐muscle‐invasive bladder cancer (NMIBC), there are limitations in accurately predicting recurrence after transurethral resection of bladder tumor (TURBT) based on clinicopathological factors alone. However, prediction of recurrence using biomolecular characteristics of bladder tumors has not been applied to clinical practice. The objective of this study was to establish a new gene expression scoring system for identifying patients at high risk of recurrence.Methods: NMIBC and normal bladder samples were subjected to microarray analysis to obtain gene expression profiles. We identified 6 genes that were specifically upregulated in bladder cancer and also in recurrent cases. All patients were randomly grouped into a discovery cohort (n = 59) and a validation cohort (n = 30). Gene expression score (GES) was defined as the mean Z‐score of the 6 genes specific for recurrent bladder cancer.Results: The intravesical recurrence rate of the high GES group (n = 38) was higher than the low GES group (n = 21). GES was significantly associated with recurrence‐free survival in the validation cohort as well. In prognostic analysis, the European Organization for Research and Treatment of Cancer (EORTC) risk classification was not related to recurrence after TURBT in either univariate or multivariate analysis. On the other hand, the GES we developed was an independent factor for recurrence in NMIBC.Conclusions: A novel gene expression scoring system was shown to predict recurrence in NMIBC patients after TURBT and might be helpful in clinical decision‐making for NMIBC patients.

Background: In the global ARASENS study (NCT02799602), darolutamide plus androgen‐deprivation therapy (ADT) and docetaxel significantly reduced risk of death by 32.5% versus placebo plus ADT and docetaxel (hazard ratio [HR] 0.68; 95% confidence interval [CI] 0.57–0.80; p < 0.0001), with a favorable safety profile in patients with metastatic hormone‐sensitive prostate cancer (mHSPC). We investigated outcomes in Japanese participants. Methods: Patients were randomized 1:1 to oral darolutamide 600 mg twice daily or placebo, plus ADT and docetaxel. The primary endpoint was overall survival. Results: The Japanese subgroup comprised 148 patients (darolutamide 63, placebo 85). In the Japanese versus overall population, more patients were aged ≥75 years (darolutamide/placebo 35%/22% vs. 16%/17%) and had body mass index 2 (78%/79% vs. 46%/43%), The ECOG performance status 0 (92%/88% vs. 72%/71%), de novo mHSPC (95%/97% vs. 86%/87%), and Gleason score ≥8 (94%/92% vs. 78%/79%). Median treatment duration was 43.3/15.4 months for darolutamide/placebo. The overall survival HR for darolutamide versus placebo was 0.91 (95% CI 0.50–1.64), despite 85% of patients in the placebo group receiving subsequent life‐prolonging therapy. Darolutamide prolonged time to castration‐resistant prostate cancer (HR 0.31; 95% CI 0.17–0.55). Treatment‐emergent adverse event incidences were generally similar between groups. Adverse events known to be associated with docetaxel (e.g., neutropenia) were more frequent in the Japanese versus overall population. Conclusion: In conclusion, efficacy outcomes showed positive trends for darolutamide plus ADT and docetaxel in Japanese patients with mHSPC, consistent with the overall population, despite higher risk factors. The combination was well tolerated, with no new safety signals in Japanese patients.

Alternative anti-androgen therapy has been widely used as a first-line treatment for castration-resistant prostate cancer, and it may affect treatment outcome of subsequent agents targeting the androgen receptor axis. We conducted the prospective observational DELC (Determination of Enzalutamide Long-term safety and efficacy for Castration-resistant prostate cancer patients after combined anti-androgen blockade followed by alternative anti-androgen therapy) study to evaluate the efficacy of enzalutamide in patients with castration-resistant prostate cancer who underwent prior combined androgen blockade with bicalutamide and then alternative anti-androgen therapy with flutamide. The DELC study enrolled 163 Japanese patients with castration-resistant prostate cancer who underwent alternative anti-androgen therapy with flutamide following failure of initial combined androgen blockade with bicalutamide in multiple institutions between January 2016 and March 2019. Primary endpoint was overall survival. Administration of enzalutamide was started at 160 mg orally once daily in all patients. The rate of decline of prostate-specific antigen by 50% or more was 72.2%, and median overall survival was 42.05 months. Multivariate analysis revealed that higher pretreatment serum levels of prostate-specific antigen (≥11.3 ng/mL; P = 0.004), neuron-specific enolase (P = 0.014) and interleukin-6 (≥2.15 pg/mL; P = 0.004) were independent risk factors for overall survival. Fatigue (30.0%), constipation (19.6%) and appetite loss (17.8%) were the most common clinically relevant adverse events. The enzalutamide dose was not reduced in any patient under the age of 70, but adherence was decreased in those over 70. In the DELC study, the safety of enzalutamide was comparable to that in previous reports. Serum levels of neuron-specific enolase and interleukin-6 were suggested as prognostic factors for castration-resistant prostate cancer with potential clinical utility.

Background Alternative antiandrogen therapy (AAT) has been widely used as a first-line treatment for castration-resistant prostate cancer (CRPC), and it may affect treatment outcome of subsequent androgen receptor axis-targeted agents. We conducted a prospective observational study to evaluate the efficacy of enzalutamide in patients with CRPC who underwent prior combined androgen blockade with bicalutamide and then AAT with flutamide. Methods This prospective observational study enrolled 163 Japanese patients with CRPC who underwent AAT with flutamide following failure of initial combined androgen blockade with bicalutamide in multiple institutions between January 2016 and March 2019. Primary endpoint was overall survival. Administration of enzalutamide was started at 160 mg orally once daily in all patients. Results Median follow-up period was 25.8 months, the rate of decline of prostate-specific antigen by 50% or more was 72.2%, and median overall survival was 42.05 months. Multivariate analysis revealed that higher pretreatment serum prostate-specific antigen (≥ 11.3 ng/mL; p = 0.004), higher neuron-specific enolase (p = 0.014), and higher serum interleukin-6 (≥ 2.15 pg/mL; p = 0.004) levels were independent risk factors for overall survival. Fatigue (30.0%), constipation (19.6%), and appetite loss (17.8%) were the most common clinically relevant adverse events. The enzalutamide dose was not reduced in any patient under the age of 70, but adherence was decreased in those over 70. Conclusions Although the enzalutamide response period appeared shorter due to prior AAT, overall survival was deemed equivalent compared to previous reports. Neuron-specific enolase and interleukin-6 levels in serum were suggested as prognostic factors with potential clinical utility.

Theranostics (therapy + diagnosis) targeting prostate-specific membrane antigen (PSMA) is an emerging therapeutic modality that could alter treatment strategies for prostate cancer. Although PSMA-targeted radioligand therapy (PSMA-RLT) has a highly therapeutic effect on PSMA-positive tumor tissue, the efficacy of PSMA-RLT depends on PSMA expression. Moreover, predictors of treatment response other than PSMA expression are under investigation. Therefore, the optimal patient population for PSMA-RLT remains unclear. This review provides an overview of the current status of theranostics for prostate cancer, focusing on PSMA ligands. In addition, we summarize various findings regarding the efficacy and problems of PSMA-RLT and discuss the optimal patient for PSMA-RLT.

Benign prostatic hyperplasia (BPH) is a chronic proliferative disease showing stromal-dominant proliferation. However, the detailed proliferation mechanism has remained unclear. Although aging and androgen have been reported as definitive risk factors for BPH, recent studies have focused on the involvement of androgen-independent factors. Androgen-independent factors include ischemia, oxidative stress, metabolic syndrome, infection, autoimmune reactions, and inflammation, with inflammation in BPH tissues playing a central role in the BPH proliferative process. Inflammation in BPH tissues by various factors finally leads to tissue remodeling and stromal proliferation through the wound healing process of the prostate. To elucidate the proliferative mechanism of BPH, a study using whole-genome gene expression analysis in a stromal-dominant BPH rat model was performed and showed that immune response-related pathways and complement classical pathways are activated. Furthermore, expression analysis using this BPH rat model showed that the autoimmune reaction triggered complement pathway activation in the proliferative process of BPH. BPH is a multifactorial disease, and understanding the role of androgen-independent factors including immune responses contributes to elucidating the pathogenesis of BPH. Androgen-independent factors may lead to new therapeutic targets for BPH, and further development of this research is expected.

In the treatment of cancer, understanding the disease status, or accurate staging, is extremely important, and various imaging techniques are used. Computed tomography (CT), magnetic resonance imaging, and scintigrams are commonly used for solid tumors, and advances in these technologies have improved the accuracy of diagnosis. In the clinical practice of prostate cancer, CT and bone scans have been considered especially important for detecting metastases. Nowadays, CT and bone scans are called conventional methods because positron emission tomography (PET), especially prostate-specific membrane antigen (PSMA)/PET, is extremely sensitive in detecting metastases. Advances in functional imaging, such as PET, are advancing the diagnosis of cancer by allowing information to be added to the morphological diagnosis. Furthermore, PSMA is known to be upregulated depending on the malignancy of the prostate cancer grade and resistance to therapy. Therefore, it is often highly expressed in castration-resistant prostate cancer (CRPC) with poor prognosis, and its therapeutic application has been attempted for around two decades. PSMA theranostics refers to a type of cancer treatment that combines both diagnosis and therapy using a PSMA. The theranostic approach uses a radioactive substance attached to a molecule that targets PSMA protein on cancer cells. This molecule is injected into the patient’s bloodstream and can be used for both imaging the cancer cells with a PET scan (PSMA PET imaging) and delivering radiation directly to the cancer cells (PSMA-targeted radioligand therapy), with the aim of minimizing damage to healthy tissue. Recently, in an international phase III trial, the impact of ¹⁷⁷Lu-PSMA-617 therapy was studied in patients with advanced PSMA-positive metastatic CRPC who had previously been treated with specific inhibitors and regimens. The trial revealed that ¹⁷⁷Lu-PSMA-617 significantly extended both progression-free survival and overall survival compared to standard care alone. Although there was a higher incidence of grade 3 or above adverse events with ¹⁷⁷Lu-PSMA-617, it did not negatively impact the patients’ quality of life. PSMA theranostics is currently being studied and used primarily for the treatment of prostate cancer, but it has the potential to be applied to other types of cancers as well.