Remarkable Improvement of Diabetic Nephropathy in Transplanted Allograft after Kidney Transplantation.

Although glomerular damage caused by diabetic nephropathy was thought to be irreversible, in recent years, there have been reports on improvement in glomerular damage with strict glycemic control. However, few reports are available on the pathologic course after renal transplantation of donor-derived grafts with findings of diabetic nephropathy. A 53-year-old woman underwent an ABO blood-type compatible living-donor renal transplant. The recipient had no history of diabetes, and fasting blood glucose and hemoglobin A1c levels were both normal. The donor was a 57-year-old male who had received treatment for type 2 diabetes mellitus for 10 years. Transplant renal biopsy performed 1 h after revascularization showed mesangial matrix expansion and arterial hyalinosis due to diabetic nephropathy. The blood glucose level was within the normal range after transplantation. Mesangial matrix expansion and arterial hyalinosis disappeared in allograft biopsy samples 7 years after transplantation. We observed significant improvement in the pathological findings of donor-derived diabetic nephropathy after renal transplantation in the subsequent follow-ups.

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: a multicenter prospective DELC study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Primary renal peripheral T-cell lymphoma, not otherwise specified, treated with partial nephrectomy.

Introduction: Renal involvement by non-Hodgkin's lymphoma is very rare, and the kidney as the primary site of this lymphoma is much more uncommon. We report a case of primary renal peripheral T-cell lymphoma, not otherwise specified, treated with partial nephrectomy. Case presentation: A 63-year-old man was hospitalized with coronavirus infectious disease, emerged in 2019 in the emergency department. Computed tomography examination showed a 2-cm renal mass in the right kidney. Abdominal enhanced computed tomography examination revealed that the noted mass showed good enhancement in the corticomedullary phase and washout in the nephrogenic phase. No metastatic lesions were found. He was diagnosed as having cT1aN0M0 renal cell carcinoma, and robotic-assisted partial nephrectomy was carried out. The pathological diagnosis was peripheral T-cell lymphoma, not otherwise specified. He has been followed for 20 months after robotic-assisted partial nephrectomy without additional treatment and recurrence. Conclusion: We experienced a primary renal peripheral T-cell lymphoma, not otherwise specified that was followed up without treatment after surgery.

The Japanese Urological Association's clinical practice guidelines for urotrauma 2023.

The Japanese Urological Association's guidelines for the treatment of renal trauma were published in 2016. In conjunction with its revision, herein, we present the new guidelines for overall urotrauma. Its purpose is to provide standard diagnostic and treatment recommendations for urotrauma, including iatrogenic trauma, to preserve organ function and minimize complications and fatality. The guidelines committee comprised urologists with experience in urotrauma care, selected by the Trauma and Emergency Medicine Subcommittee of the Specialty Area Committee of the Japanese Urological Association, and specialists recommended by the Japanese Association for the Surgery of Trauma and the Japanese Society of Interventional Radiology. The guidelines committee established the domains of renal and ureteral, bladder, urethral, and genital trauma, and determined the lead person for each domain. A total of 30 clinical questions (CQs) were established for all domains; 15 for renal and ureteral trauma and five each for the other domains. An extensive literature search was conducted for studies published between January 1, 1983 and July 16, 2020, based on the preset keywords for each CQ. Since only few randomized controlled trials or meta-analyses were found on urotrauma clinical practice, conducting a systematic review and summarizing the evidence proved challenging; hence, the grade of recommendation was determined according to the 2007 "Minds Handbook for Clinical Practice Guidelines" based on a consensus reached by the guidelines committee. We hope that these guidelines will be useful for clinicians in their daily practice, especially those involved in urotrauma care.

A case of robot-assisted laparoscopic partial nephrectomy during pregnancy.

Introduction: Malignancy during pregnancy requires consideration of both the mother and fetus. We report a patient with renal cell carcinoma during pregnancy who was treated with robot-assisted partial nephrectomy. Case presentation: The patient was incidentally found to have a renal mass on abdominal ultrasonography. Definitive diagnosis of cT1aN0M0 RCC was made by enhanced computed tomography. Subsequently, pregnancy was discovered. RAPN was performed without complications. Pathologic examination revealed clear cell RCC. There were no postoperative complications, and the baby was born safely. Conclusion: RAPN can be safe and effective even during pregnancy. Every pregnant patient requires individualized treatment involving the timing of surgery, the procedure used, and management based on the condition of the mother and fetus, tumor stage, and the experience of the surgical team.

A case of abiraterone acetate withdrawal syndrome after initiation of upfront abiraterone therapy for high-risk prostate cancer.

Introduction: Transient decrease in serum prostate-specific antigen level can occur after abiraterone acetate withdrawal in male patient with metastatic castration-resistant prostate cancer. Here, we report a case of abiraterone acetate withdrawal syndrome with transient prostate-specific antigen decrease after progression to castration-resistant disease while using upfront abiraterone therapy for high-risk prostate cancer. Case presentation: A 73-year-old man with hormone-sensitive high-risk prostate cancer with multiple bone metastases (prostate-specific antigen level, 294.109 ng/mL) received upfront abiraterone/prednisolone combination and androgen deprivation therapy. One year later, prostate-specific antigen level decreased to 0.017 ng/mL (nadir) but it gradually rose by 15 months after treatment initiation. He was diagnosed as castration-resistant and new bone metastases appeared. After abiraterone was discontinued, prostate-specific antigen level decreased and stabilized at a low level for 5 months. Conclusion: Abiraterone acetate withdrawal syndrome was observed when hormone-sensitive prostate cancer with upfront abiraterone therapy progressed to castration-resistant prostate cancer.

Upside-Down Kidney Transplantation in a Recipient with Severe Arteriosclerosis: A Case Report.

Recently, the number of patients with significant arteriosclerosis has been increasing owing to the aging of kidney transplant patients, an increase in the number of patients with kidney failure with diabetes as the primary disease, and an increase in the number of patients undergoing long-term dialysis. Severe atherosclerosis in kidney transplant recipients makes it difficult to determine the site of vascular anastomosis and increases the technical difficulty of the surgical procedure. This study presents a case of upside-down kidney transplantation in a recipient with severe arteriosclerosis. The patient was a 58-year-old male with diabetic nephropathy. He received an ABO-compatible living donor kidney transplant from his wife. Preoperative computed tomography revealed a mild calcification of the external iliac artery. However, during surgery, more than half of the external iliac artery was found to be calcified, making vascular anastomosis difficult. The peripheral side of the external iliac artery showed mild atherosclerosis. Therefore, the vessel could be anastomosed to the peripheral side of the external iliac artery by turning the kidney graft upside-down for use as the anastomosis site. The postoperative course was uneventful, and the kidney function was good at the last follow-up. Upside-down kidney transplantation is safe in patients with severe arteriosclerosis.

A case of hypogonadtropic hypogonadism due to hypophysitis discovered by secondary male infertility.

Introduction: The main causes of secondary male infertility are varicocele and aging. It is rarely caused by adult-onset hypopituitarism. The onset of hypopituitarism is often due to brain tumors, trauma, surgery, or congenital disorders. Case presentation: A 29-year-old man was admitted to the hospital with complaints of decreased libido and semen volume, which lasted for 4 months. He had no abnormalities in adolescence and has a 2-year-old child. Blood tests showed low luteinizing hormone and follicle-stimulating hormone, and semen tests showed azoospermia. Magnetic resonance imaging T1-weighted images showed swelling and enhancement effect of the pituitary gland, and lymphocytic hypophysitis was suspected. After an Insulin-thyroid-stimulating hormone releasing hormone-luteinizing hormone-releasing hormone test, a decrease in luteinizing hormone/follicle-stimulating hormone secretion was considered. We diagnosed hypogonadotropic hypogonadism due to lymphocytic hypophysitis. Currently, the patient is being treated with a hormone replacement therapy. Conclusion: We experienced a case of hypogonadotropic hypogonadism due to lymphocytic hypophysitis discovered by secondary infertility.

Immunohistochemical Analysis of HER2, EGFR, and Nectin-4 Expression in Upper Urinary Tract Urothelial Carcinoma.

BACKGROUND/AIM: Upper urinary tract urothelial carcinoma (UTUC) is a rare disease, often discovered at an advanced stage at diagnosis. Nectin-4 is expressed in a broad range of patients with UTUC and is associated with poor progression-free survival. The receptors of the erythroblastosis oncogene B (ErbB) family are potential therapeutic targets for urothelial carcinoma. Herein, we aimed to investigate the relationship of nectin-4 and ErbB family receptors, namely epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) in patients with UTUC. Targeted therapies for these receptors could be used in sequence or in combination for increasing treatment efficiency. PATIENTS AND METHODS: We performed immunohisto-chemical analysis for HER2, EGFR, and nectin-4 using tissue microarrays. A total of 98 UTUC patients were included in the study. We investigated the impact of EGFR and HER2 expression status on recurrence-free survival (RFS) and cancer-specific survival (CSS) of all patients. RESULTS: The percentages of patients positive for HER2, EGFR, and nectin-4 were 97%, 70%, and 65%, respectively. The co-expression rates of HER2-EGFR, HER2-nectin-4, and EGFR-nectin-4 were 69%, 64%, and 47%, respectively. The number of patients positive for all three receptors was 47%. Higher HER2 levels were significantly associated with worse CSS and RFS. Higher EGFR levels were associated with a worse CSS. CONCLUSION: HER2, EGFR, and nectin-4 were highly expressed in UTUC. Combination of HER2-, EGFR-, and nectin-4-targeted therapy may be an effective option for the treatment of patients with UTUC.

A comparative study on nivolumab and axitinib as secondary treatment in patients with metastatic renal cell carcinoma: A multi-institutional retrospective study in Japan.

OBJECTIVES: When primary treatment has been inadequate, nivolumab and axitinib are often used as a secondary treatments for patients with metastatic renal cell carcinoma (mRCC). However, there have been few reports comparing the efficacy and safety of these drugs. METHODS: We retrospectively investigated 58 patients treated with nivolumab and 57 patients treated with axitinib as secondary treatment between April 2013 and December 2019. We then assessed the clinical efficacy and safety of the treatments in both groups. RESULTS: The most common primary therapy was sunitinib (61.7%). Both nivolumab and axitinib groups showed no significant differences in terms of the objective response rate and disease control rate (p = 0.280 and p = 0.518, respectively). Importantly, progression-free survival (PFS) and overall survival (OS) seemed to be similar in patients treated with nivolumab and axitinib (p = 0.527 and p = 0.266, respectively), irrespective of the objective response to primary therapy. Furthermore, a Cox proportional hazards model showed that pretreatment Karnofsky Performance Status was significantly associated with PFS and OS. Although the incidence of adverse events was significantly higher in the patients treated with axitinib, there was no significant difference in time to treatment failure between the two groups. CONCLUSIONS: Nivolumab and axitinib showed similar clinical benefits as secondary treatment in patients with mRCC; thus, they should be an option in sequential therapy following treatment with tyrosine kinase inhibitors (TKIs). Future studies and feasible therapeutic biomarkers would help predict the clinical response to TKIs or immune checkpoint inhibitors in patients with mRCC.

[A Case of Metanephric Adenoma Treated with Robotic-Assisted Laparoscopic Partial Nephrectomy].

A 53-year-old female patient was diagnosed with a left renal mass incidentally detected on an abdominal computed tomography (CT) scan. Further examination revealed a slightly contrast-enhancing mass 2.0 cm in diameter, in the left kidney on a contrast-enhanced CT scan. A diagnosis of left renal cell carcinoma (cT1aN0M0) was made and a robotic-assisted laparoscopic partial nephrectomy was performed. The excised tissue specimen exhibited a clearly circumscribed tumor. On hematoxylin eosin staining, the small uniform tumor cells appeared organized in glandular luminal arrangements, with lacking nuclear atypia and any malignant features. Immunostaining confirmed the diagnosis as metanephric adenoma, as indicated by positive results for WT1 and negative results for alpha-methylacyl-CoA race mase. Metanephric adenoma is an uncommon benign epithelial tumor of the kidney, which frequently poses a challenge in differential diagnosis with renal carcinoma on preoperative imaging. Pathologically, it can be challenging to differentiate from papillary renal cell carcinoma, and immunostaining can be used to effectively differentiate between the two entities.

EphA2 on urinary extracellular vesicles as a novel biomarker for bladder cancer diagnosis and its effect on the invasiveness of bladder cancer.

BACKGROUND: Urinary extracellular vesicles (uEVs) secreted from bladder cancer contain cancer-specific proteins that are potential diagnostic biomarkers. We identified and evaluated a uEV-based protein biomarker for bladder cancer diagnosis and analysed its functions. METHODS: Biomarker candidates, selected by shotgun proteomics, were validated using targeted proteomics of uEVs obtained from 49 patients with and 48 individuals without bladder cancer, including patients with non-malignant haematuria. We developed an enzyme-linked immunosorbent assay (ELISA) for quantifying the uEV protein biomarker without ultracentrifugation and evaluated urine samples from 36 patients with and 36 patients without bladder cancer. RESULTS: Thirteen membrane proteins were significantly upregulated in the uEVs from patients with bladder cancer in shotgun proteomics. Among them, eight proteins were validated by target proteomics, and Ephrin type-A receptor 2 (EphA2) was the only protein significantly upregulated in the uEVs of patients with bladder cancer, compared with that of patients with non-malignant haematuria. The EV-EphA2-CD9 ELISA demonstrated good diagnostic performance (sensitivity: 61.1%, specificity: 97.2%). We showed that EphA2 promotes proliferation, invasion and migration and EV-EphA2 promotes the invasion and migration of bladder cancer cells. CONCLUSIONS: We established EV-EphA2-CD9 ELISA for uEV-EphA2 detection for the non-invasive early clinical diagnosis of bladder cancer.

Real-world efficacy and safety of nivolumab plus ipilimumab in untreated metastatic renal cell carcinoma, and the impact of previous nephrectomy on clinical outcome: Japanese multi-institutional retrospective study.

BACKGROUND: In metastatic renal-cell carcinoma (mRCC), recent clinical trials have shown efficacy of first-line combination therapy, as evidenced by better clinical outcome over target therapy. However, there are insufficient real-world evidences in mRCC patients in Japan. METHODS: We performed a multicenter retrospective study of 72 mRCC patients who received nivolumab plus ipilimumab as first-line treatment between September 2018 and July 2021. Patient's characteristics, clinical outcomes and safety were retrospectively reviewed. We analyzed overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) in patients treated with combination therapy. RESULTS: Of all patients, the median age was 70 years (range, 36-86) and the major type of histology was clear cell RCC (n = 55; 76.4%). Progressive disease (n = 25; 34.8%) and irAEs (n = 22; 30.6%) were the most common causes for discontinuing treatment. Median PFS and OS seemed similar between patients who discontinued treatment because of irAEs and for patients who did not (p = 0.360 and p = 0.069, respectively). Importantly, for patients with synchronous metastatic disease at diagnosis (n = 56), nephrectomy before initiating nivolumab plus ipilimumab had a significantly positive impact on better OS when compared to that in patients without nephrectomy (p = 0.028). CONCLUSION: This study confirms efficacy and safety of nivolumab plus ipilimumab for mRCC patients in real-world settings. Furthermore, nivolumab plus ipilimumab was associated with a better outcome in patients who had undergone nephrectomy at diagnosis for synchronous mRCC.

Trop-2 in Upper Tract Urothelial Carcinoma.

Trophoblast cell surface antigen 2 (Trop-2, encoded by TACSTD2) is the target protein of sacituzumab govitecan, a novel antibody-drug conjugate for locally advanced or metastatic urothelial carcinoma. However, the expression status of Trop-2 in upper tract urothelial carcinoma (UTUC) remains unclear. We performed immunohistochemical analysis of 99 UTUC samples to evaluate the expression status of Trop-2 in patients with UTUC and analyze its association with clinical outcomes. Trop-2 was positive in 94 of the 99 UTUC samples, and high Trop-2 expression was associated with favorable progression-free survival (PFS) and cancer-specific survival (p = 0.0011, 0.0046). Multivariate analysis identified high Trop-2 expression as an independent predictor of favorable PFS (all cases, p = 0.045; high-risk group (pT3≤ or presence of lymphovascular invasion or lymph node metastasis), p = 0.014). Gene expression analysis using RNA sequencing data from 72 UTUC samples demonstrated the association between high TACSTD2 expression and favorable PFS (all cases, p = 0.069; high-risk group, p = 0.029). In conclusion, we demonstrated that Trop-2 is widely expressed in UTUC. Although high Trop-2 expression was a favorable prognostic factor in UTUC, its widespread expression suggests that sacituzumab govitecan may be effective for a wide range of UTUC.

Everolimus Reduces Cancer Incidence and Improves Patient and Graft Survival Rates after Kidney Transplantation: A Multi-Center Study.

Kidney transplantation can prevent renal failure and associated complications in patients with end-stage renal disease. Despite the good quality of life, de novo cancers after kidney transplantation are a major complication impacting survival and there is an urgent need to establish immunosuppressive protocols to prevent de novo cancers. We conducted a multi-center retrospective study of 2002 patients who underwent kidney transplantation between 1965 and 2020 to examine patient and graft survival rates and cumulative cancer incidence in the following groups categorized based on specific induction immunosuppressive therapies: group 1, antiproliferative agents and steroids; group 2, calcineurin inhibitors (CNIs), antiproliferative agents and steroids; group 3, CNIs, mycophenolate mofetil, and steroids; and group 4, mammalian target of rapamycin inhibitors including everolimus, CNIs, mycophenolate mofetil, and steroids. The patient and graft survival rates were significantly higher in groups 3 and 4. The cumulative cancer incidence rate significantly increased with the use of more potent immunosuppressants, and the time to develop cancer was shorter. Only one patient in group 4 developed de novo cancer. Potent immunosuppressants might improve graft survival rate while inducing de novo cancer after kidney transplantation. Our data also suggest that everolimus might suppress cancer development after kidney transplantation.

Clinical effect of rabbit anti-thymocyte globulin for chronic active antibody-mediated rejection after kidney transplantation.

Chronic active antibody-mediated rejection (CAAMR) is a frequent cause of late graft loss. However, effective treatment for CAAMR after kidney transplantation has not yet been established. Here, we present the case of a kidney transplant recipient who recovered from CAAMR after administration of rabbit anti-thymocyte globulin. A 61-year-old man underwent ABO-compatible living-donor kidney transplantation for end-stage kidney disease; the kidney was donated by his wife. Five years after the transplant, the patient's serum creatinine level and urine protein-to-creatinine ratio increased. He was subsequently diagnosed with CAAMR based on the kidney allograft biopsy and the presence of donor-specific human leukocyte antigen antibodies. Rabbit anti-thymocyte globulin treatment was administered following steroid pulse therapy. Subsequently, his serum creatinine levels and urine protein to creatinine ratio improved. There was also an improvement in the pathological findings seen on biopsy and the mean fluorescence intensity of donor-specific antibodies. In conclusion, this report describes the case of a kidney transplant recipient who developed CAAMR, treated using rabbit anti-thymocyte globulin. This strategy might be a viable treatment option for CAAMR after a kidney transplant.

[Robot-Assisted Partial Nephrectomy for Renal Cell Carcinoma Complicated by Leriche Syndrome : A Case Report].

A 71-year-old man was referred to our hospital for treatment of a 2 cm-sized right renal mass incidentally found by computed tomography (CT) and was diagnosed with right renal cell carcinoma cT1aN0M0. Contrast-enhanced CT revealed that the aorta was completely occluded below the inferior mesenteric artery origin, and Leriche syndrome was diagnosed. CT angiography showed several collateral arteries along the abdominal wall. A robot-assisted laparoscopic partial nephrectomy was performed to treat renal cell carcinoma. Preoperatively, we marked the collateral arteries using ultrasonography to avoid injury during trocar insertion. We did not observe any decrease in blood flow in the right leg during the operation. The pathological diagnosis was clear cell renal cell carcinoma. Leriche syndrome is a chronic occlusive disease involving the infrarenal aorta and the iliac arteries. Since lower limb blood flow is dependent on collateral circulation, it is important to avoid injuring the collateral arteries during surgery.

Real-world Outcomes of Tyrosine Kinase Inhibitors Immediately After Immune Checkpoint Inhibitors in Renal Cell Carcinoma.

BACKGROUND/AIM: Immune checkpoint inhibitors (ICIs) have demonstrated a survival benefit for patients with cancer. However, the clinical outcomes of subsequent tyrosine kinase inhibitors (TKIs) after ICI failure in patients with metastatic renal cell carcinoma (mRCC) remain unclear. PATIENTS AND METHODS: We retrospectively examined 38 patients with mRCC who started TKIs immediately after nivolumab with (combination group) or without ipilimumab (nivolumab group) between September 2016 and July 2019. RESULTS: Of the 38 patients, 16 and 11 achieved partial response and stable disease, respectively, resulting in a 42.1% objective response rate and 71.1% disease control rate. The median progression-free survival (PFS) from TKI initiation was 8.8 and 12.9 months in the nivolumab and combination groups, respectively. PFS and overall survival were significantly longer in patients with long-term responses to previous ICI treatment (p=0.0152 and p=0.0155, respectively). CONCLUSION: TKIs demonstrate adequate anti-tumour activity after treatment with ICIs in real-world settings.

The Firmicutes/Bacteroidetes ratio of the human gut microbiota is associated with prostate enlargement.

BACKGROUND: The pathophysiology of the prostate enlargement underlying lower urinary tract symptoms is unknown. Meanwhile, the gut microbiota can contribute to various host conditions. We hypothesized that the gut microbiota plays a role in prostate enlargement. METHODS: We included 128 patients who underwent prostate biopsies at our hospitals between December 2018 and March 2020, excluding those who had used antibiotics within the past 6 months and those who were diagnosed with prostate cancer of cT3 or higher. Patients with prostate volumes ≥30 ml were defined as the prostate-enlargement (PE) group; those with prostate volumes <30 ml were defined as the non-PE group. Their gut microbiotas were analyzed via 16S rRNA metagenomic analyses of rectal swab samples and were compared between the groups. RESULTS: The PE group included 66 patients; the non-PE group included 62 patients. Age, body mass index, and prostate-specific antigen levels did not significantly differ between the groups. Linear discriminant analysis effect size analysis indicated a higher proportion of Firmicutes and Actinobacteria in the PE group and a higher proportion of Bacteroidetes in the non-PE group. The Firmicutes/Bacteroidetes (F/B) ratio was significantly higher in the PE group than in the non-PE group (2.21 ± 0.39 vs. 1.61 ± 0.40, p = 0.015). CONCLUSION: The F/B ratio of the gut microbiota was associated with prostate enlargement. Although the detailed mechanisms are unclear, the gut microbiota might affect prostate enlargement.

The gut microbiota associated with high-Gleason prostate cancer.

We have found that intestinal bacteria and their metabolites, short-chain fatty acids (SCFAs), promote cancer growth in prostate cancer (PCa) mouse models. To clarify the association between gut microbiota and PCa in humans, we analyzed the gut microbiota profiles of men with suspected PCa. One hundred and fifty-two Japanese men undergoing prostate biopsies (96 with cancer and 56 without cancer) were included in the study and randomly divided into two cohorts: a discovery cohort (114 samples) and a test cohort (38 samples). The gut microbiota was compared between two groups, a high-risk group (men with Grade group 2 or higher PCa) and a negative + low-risk group (men with negative biopsy or Grade group 1 PCa), using 16S rRNA gene sequencing. The relative abundances of Rikenellaceae, Alistipes, and Lachnospira, all SCFA-producing bacteria, were significantly increased in high-risk group. In receiver operating characteristic curve analysis, the index calculated from the abundance of 18 bacterial genera which were selected by least absolute shrinkage and selection operator regression detected high-risk PCa in the discovery cohort with higher accuracy than the prostate specific antigen test (area under the curve [AUC] = 0.85 vs 0.74). Validation of the index in the test cohort showed similar results (AUC = 0.81 vs 0.67). The specific bacterial taxa were associated with high-risk PCa. The gut microbiota profile could be a novel useful marker for the detection of high-risk PCa and could contribute to the carcinogenesis of PCa.