Polyomavirus Replication and Smoking Are Independent Risk Factors for Bladder Cancer After Renal Transplantation

Genitourinary malignancies in kidney transplant recipients

Advances in immunosuppressive therapy and postoperative management have greatly improved the graft and patient survival rates after kidney transplantation; however, the incidence of post-transplant malignant tumors is increasing. Post-renal transplantation malignant tumors are associated with renal failure, immunosuppression, and viral infections. Moreover, the risk of developing cancer is higher in kidney transplant recipients than in the general population, and the tendency to develop cancer is affected by the background and environment of each patient. Recently, cancer after kidney transplantation has become the leading cause of death in Japan. Owing to the aggressive nature and poor prognosis of genitourinary malignancies, it is crucial to understand their epidemiology, risk factors, and best practices in kidney transplant recipients. This review has a special emphasis on the epidemiology, risk factors, and treatment protocols of genitourinary malignancies in kidney transplant recipients to enhance our understanding of the appropriate management strategies. Optimal immunosuppressive therapy and cancer management for these patients remain controversial, but adherence to the general guidelines is recommended.

High grade urothelial carcinoma in kidney transplant patients with a history of BK viremia - Just a coincidence?

INTRODUCTION

Kidney transplant recipients (KTR) have a three-to-four-fold increased risk of developing urothelial carcinoma (UC) compared to the general population. BK polyoma virus (BKV) infection is known to affect approximately 15% of KTR. In vitro models support a potential pathogenic role for BKV in the development of UC. We describe a series of UC in kidney transplant recipients.

METHODS

Electronic patient records were searched to identify KTR with UC who had undergone kidney only or simultaneous kidney and pancreas transplantation in a single UK center between 2009 and 2015. Where available, stored pathological samples were retrieved, re-examined and stained for SV40 as a marker of BKV using standard staining protocols for kidney biopsy samples.

RESULTS

Fourteen KTR had developed UC post-transplant. Of these, 10 KTR had a history of BKV infection post-transplant. Six of these 10 KTR developed a rare micropapillary tumor subtype of UC which is typically only found in <1% of UC cases. All six micropapillary tumor samples stained positive for SV40, including samples from metastases. Three tumor samples were available from the four KTR with no history of BKV infection and were not micropapillary subtype and were negative for SV40. Three micropapillary tumors from immunocompetent patients were examined as controls and were negative for SV40.

CONCLUSIONS

These findings would support a pathogenic role for BK virus in the development of rare micropapillary subtype urothelial tumors in the kidney transplant population.

BK polyomavirus: latency, reactivation, diseases and tumorigenesis

The identification of the first human polyomavirus BK (BKV) has been over half century, The previous epidemiological and phylogenetic studies suggest that BKV prevailed and co-evolved with humans, leading to high seroprevalence all over the world. In general, BKV stays latent and symptomless reactivation in healthy individuals. BKV has been mainly interlinked with BKV-associated nephropathy (BKVAN) in kidney-transplant recipients and hemorrhagic cystitis (HC) in hematopoietic stem cell transplant recipients (HSCTRs). However, the mechanisms underlying BKV latency and reactivation are not fully understood and lack of extensive debate. As Merkel cell polyomavirus (MCV) was identified as a pathogenic agent of malignant cutaneous cancer Merkel cell carcinoma (MCC) since 2008, linking BKV to tumorigenesis of urologic tumors raised concerns in the scientific community. In this review, we mainly focus on advances of mechanisms of BKV latency and reactivation, and BKV-associated diseases or tumorigenesis with systematical review of formerly published papers following the PRISMA guidelines. The potential tumorigenesis of BKV in two major types of cancers, head and neck cancer and urologic cancer, was systematically updated and discussed in depth. Besides, BKV may also play an infectious role contributing to HIV-associated salivary gland disease (HIVSGD) presentation. As more evidence indicates the key role of BKV in potential tumorigenesis, it is important to pay more attention on its etiology and pathogenicity in vitro and in vivo.

New Hydronephrosis in the Native Kidney Is Associated with the Development of De Novo Urinary Bladder Urothelial Carcinoma in Patients with Post-Kidney Transplantation

Increased malignancy after kidney transplantation (KT) is by far the most troublesome issue. Among these malignancies, urothelial carcinoma (UC) incidence is uniquely high in Taiwan. We want to know whether routine sonography to detect native hydronephrosis is associated with the development of de novo urinary bladder urothelial carcinoma (UBUC) in post-KT recipients. From 2003 to 2018, we retrospectively analyzed 1005 KT patients, 58 of whom were subsequently diagnosed with UBUC. The association between new native hydronephrosis and post-KT UBUC was analyzed with univariate and multivariate logistic regression analyses and a Kaplan-Meier plot. We excluded cases of people who had upper urinary tract urothelial carcinoma (UTUC) and were diagnosed prior to UBUC. There were 612 males (60.9%) and 393 females (39.1%), with a mean age of 48.2 ± 12.0 years old at KT. The mean follow-up period was 118.6 ± 70.2 months, and the diagnosis of UBUC from KT to UBUC was 7.0 ± 5.1 years. New native kidney hydronephrosis occurred more frequently in the UBUC group (56.4% versus 6.4%, p < 0.001) than the non-UBUC group. Multivariate analysis disclosed that native hydronephrosis is the only statistically significant factor for UBUC, with an odds ratio of 16.03 (95% CI, 8.66-29.68; p < 0.001). UBUC in post-KT patients with native hydronephrosis also showed a tendency toward multifocal lesions upon presentation (47.8%). Post-KT UBUC is characterized by pathologically aggressive and multiple foci lesions. Native kidney hydronephrosis may be a deciding factor of post-KT UBUC.

APOBEC3-mediated mutagenesis in cancer: causes, clinical significance and therapeutic potential

Apolipoprotein B mRNA-editing enzyme, catalytic polypeptides (APOBECs) are cytosine deaminases involved in innate and adaptive immunity. However, some APOBEC family members can also deaminate host genomes to generate oncogenic mutations. The resulting mutations, primarily signatures 2 and 13, occur in many tumor types and are among the most common mutational signatures in cancer. This review summarizes the current evidence implicating APOBEC3s as major mutators and outlines the exogenous and endogenous triggers of APOBEC3 expression and mutational activity. The review also discusses how APOBEC3-mediated mutagenesis impacts tumor evolution through both mutagenic and non-mutagenic pathways, including by inducing driver mutations and modulating the tumor immune microenvironment. Moving from molecular biology to clinical outcomes, the review concludes by summarizing the divergent prognostic significance of APOBEC3s across cancer types and their therapeutic potential in the current and future clinical landscapes.

Systematic review on oncologic outcomes on adjuvant endovesical treatment for non-muscle invasive bladder cancer in patients with solid organ transplant

PURPOSE

Urothelial carcinoma has a higher incidence in renal transplanted patients according to several registries (relative risk × 3), and the global prognosis is inferior to the general population. The potential impact of immunosuppressive therapy on the feasibility, efficacy, and complications of endovesical treatment, especially Bacillus Calmette-Guerin, has a low level of evidence. We performed a systematic review that aimed to assess the morbidity and oncological outcomes of adjuvant endovesical treatment in solid organ transplanted patients.

METHODS

Medline was searched up to December 2021 for all relevant publications reporting oncologic outcomes of endovesical treatment in solid organ transplanted patients with NMIBC. Data were synthesized in light of methodological and clinical heterogeneity.

RESULTS

Twenty-three retrospective studies enrolling 238 patients were included: 206 (96%) kidney transplants, 5 (2%) liver transplants, and 2 (1%) heart transplants. Concerning staging: 25% were pTa, 62% were pT1, and 22% were CIS. 140/238 (59%) patients did not receive adjuvant treatment, 50/238 (21%) received mitomycin C, 4/238 (2%) received epirubicin, and 46/238 (19%) received BCG. Disease-free survival reached 35% with TURBT only vs. 47% with endovesical treatment (Chi-square test p = 0.08 OR 1.2 [0.98-1.53]). The complication rate of endovesical treatment was 12% and was all minor (Clavien-Dindo I).

CONCLUSION

In solid organ transplanted patients under immunosuppressive treatment, both endovesical chemotherapy and BCG are safe, but the level of evidence concerning efficacy in comparison with the general population is low. According to these results, adjuvant treatment should be proposed for NMIC in transplanted patients as in the general population.

The Association Between Smoking and Renal Function in People Over 20 Years Old

Background

Many conclusions have been reached in renal function studies in direct smokers.

Aim

This study aimed to determine the relationship between smoking and decreased renal function to ensure that reduced chronic kidney disease incidence can be achieved by limiting smoking, we assessed the relationship between cigarette smoking and renal function.

Methods

We recruited 10,267 people from the National Health and Nutrition Program Testing Survey (NHANES) aged over 20 years from 2013 to 2018 to assess smoking exposure by serum cotinine. We estimated the glomerular filtration rate (eGFR) and used multivariate linear regression models and smooth curve fittings to assess the relationship between smoking and renal function.

Results

We found an inverse relationship between serum cotinine and the eGFR. In a subgroup analysis, we found a non-linear relationship between serum cotinine and the eGFR in different ethnic groups or in different sexes. In a subgroup analysis of sex, we found inflection points between men and women for the relationship between serum cotinine and the eGFR (men 183 ng/ml and 465 ng/ml; women 227 ng/ml and 412 ng/ml). However, in a subgroup analysis by age, we found that serum cotinine showed a clear negative correlation with the eGFR in people aged 20–39 years, but in people older than 40 years, a weak correlation was shown. In stratified analysis by ethnicity, we found significant negative associations in Mexican American and Other Hispanic individuals and weaker associations in Non-Hispanic White and Non-Hispanic Black individuals.

Conclusion

Through the negative correlation between serum cotinine and the eGFR, we can conclude that as the smoking quantity increases, smoking leads to a decrease in renal function. The results of the subgroup analysis indicate that in young people, by advocating smoking cessation early, we can very effectively prevent kidney disease in this population and thus reduce the incidence of chronic kidney disease. Smoking should be included as an independent risk factor for chronic kidney disease.

Molecular dissection on inhibition of Ras-induced cellular senescence by small t antigen of SV40

Simian virus 40 (SV40) is a potentially oncogenic virus of monkey origin. Transmission, prevalence, and pathogenicity rates of SV40 are unclear, but infection can occur in humans, for example individuals with high contact with rhesus macaques and individuals that received contaminated early batches of polio vaccines in 1950-1963. In addition, several human polyomaviruses, proven carcinogenic, are also highly common in global populations. Cellular senescence is a major mechanism of cancer prevention in vivo. Hyperactivation of Ras usually induces cellular senescence rather than cell transformation. Previous studies suggest small t antigen (ST) of SV40 may interfere with cellular senescence induced by Ras. In the current study, ST was demonstrated to inhibit Ras-induced cellular senescence (RIS) and accumulation of DNA damage in Ras-activated cells. In addition, ST suppressed the signal transmission from BRaf to MEK and thus blocked the downstream transmission of the activated Ras signal. B56γ knockdown mimicked the inhibitory effects of ST overexpression on RIS. Furthermore, KSR1 knockdown inhibited Ras activation and the subsequent cellular senescence. Further mechanism studies indicated that the phosphorylation level of KSR1 rather than the levels of the total protein regulates the activation of Ras signaling pathway. In sum, ST inhibits the continuous hyperactivation of Ras signals by interfering with the normal functions of PP2A-B56γ of dephosphorylating KSR1, thus inhibiting the occurrence of cellular senescence. Although the roles of SV40 in human carcinogenesis are controversial so far, our study has shown that ST of polyomaviruses has tumorigenic potential by inhibiting oncogene-induced senescence (OIS) as a proof of concept.

BK virus associated with small cell carcinoma of bladder in a patient with renal transplant

A man in his 70s with a complex medical history, including cadaveric renal transplant, presented with recurrent urinary tract infections. Investigation revealed recurrent urinary pathogens, including Enterobacter cloacae and persistent BK viruria. Cystoscopy revealed a pedunculated mass in the right posterior-lateral wall, inferior to the transplant urethral orifice, and biopsy of this mass showed invasive small cell carcinoma with a prominent adenocarcinoma component. The tumour was treated with complete transurethral resection followed by carboplatin, etoposide and radiation. Laboratory analysis of biopsied samples showed immunostaining and molecular evidence of BK virus DNA in the cancer cells. Follow-up cystoscopies have shown no recurrence of the cancer.

Urological Cancers and Kidney Transplantation: a Literature Review

PURPOSE OF REVIEW

The aim of this review is to provide an overview of epidemiology, risk factors, and treatment of urological malignancies in renal transplant recipients (RTR).

RECENT FINDINGS

Although optimal immunosuppressive therapy and cancer management in these patients remain controversial, adherence to general guidelines is recommended. Kidney transplantation is recognized as the standard of care for the treatment of end-stage renal disease (ESRD) as it offers prolonged survival and better quality of life. In the last decades, survival of RTRs has increased as a result of improved immunosuppressive therapy; nonetheless, the risk of developing cancer is higher among RTRs compared to the general population. Urological malignancies are the second most common after hematological cancer and often have more aggressive behavior and poor prognosis.

How to manage cigarette smoking in kidney transplant candidates and recipients?

Tobacco smoking is a frequent problem affecting many kidney transplant (KT) candidates and recipients. The negative impact of active smoking on KT outcomes has been demonstrated. Consequently, most guidelines strongly recommend quitting smoking before considering kidney transplantation. However, nicotine addiction is a complex multifactorial disease and only 3-5% of the patients who try to quit by themselves achieve prolonged abstinence. Smoking cessation programmes (SCPs) have proven their efficacy in the general population to increase the rate of quitting and should therefore be proposed to all smoking KT candidates and recipients. Nevertheless, SCPs have not been evaluated in the KT field and not all KT centres have easy access to these programmes. In this work, we aim to review the current knowledge on the subject and provide an overview of the available interventions to help smoking patients quit. We detail non-pharmaceutical and pharmaceutical approaches and discuss their use in KT candidates and recipients.

Risk factors, management, and survival of bladder cancer after kidney transplantation

INTRODUCTION AND OBJECTIVES

Kidney transplantation is associated with an increased risk of bladder cancer; however guidelines have not been established on the management of bladder cancer after kidney transplantation.

MATERIALS AND METHODS

A systematic literature review using PubMed was performed in accordance with the PRISMA statement to identify studies concerning the prevalence and survival of bladder cancer after kidney transplantation. The risk factors and management of bladder cancer after kidney transplantation were also reviewed and discussed.

RESULTS

A total of 41 studies, published between 1996 and 2018, reporting primary data on bladder cancer after kidney transplantation were identified. Marked heterogeneity in bladder cancer prevalence, time to diagnosis, non-muscle invasive/muscle-invasive bladder cancer prevalence, and survival was noted. Four studies, published between 2003 and 2017, reporting primary data on bladder cancer treated with Bacillus Calmette-Guérin (BCG) after kidney transplantation were identified. Disease-free survival, cancer-specific survival, and overall survival were similar between BCG studies (75-100%).

CONCLUSIONS

Carcinogen exposure that led to ESRD, BKV, HPV, immunosuppressive agents, and the immunosuppressed state likely contribute to the increased risk of bladder cancer after renal transplantation. Non-muscle invasive disease should be treated with transurethral resection. BCG can be safely used in transplant recipients and likely improves the disease course. Muscle-invasive disease should be treated with radical cystectomy, with special consideration to the dissection and urinary diversion choice. Chemotherapy and immune checkpoint inhibitors can be safely used in regionally advanced bladder cancer with potential benefit. mTOR inhibitors may reduce the risk of developing bladder cancer, and immunosuppression medications should be reduced if malignancy develops.

Risk factors, management, and survival of bladder cancer after kidney transplantation

INTRODUCTION AND OBJECTIVES

Kidney transplantation is associated with an increased risk of bladder cancer; however guidelines have not been established on the management of bladder cancer after kidney transplantation.

MATERIALS AND METHODS

A systematic literature review using PubMed was performed in accordance with the PRISMA statement to identify studies concerning the prevalence and survival of bladder cancer after kidney transplantation. The risk factors and management of bladder cancer after kidney transplantation were also reviewed and discussed.

RESULTS

A total of 41 studies, published between 1996 and 2018, reporting primary data on bladder cancer after kidney transplantation were identified. Marked heterogeneity in bladder cancer prevalence, time to diagnosis, non-muscle invasive/muscle-invasive bladder cancer prevalence, and survival was noted. Four studies, published between 2003 and 2017, reporting primary data on bladder cancer treated with Bacillus Calmette-Guérin (BCG) after kidney transplantation were identified. Disease-free survival, cancer-specific survival, and overall survival were similar between BCG studies (75-100%).

CONCLUSIONS

Carcinogen exposure that led to ESRD, BKV, HPV, immunosuppressive agents, and the immunosuppressed state likely contribute to the increased risk of bladder cancer after renal transplantation. Non-muscle invasive disease should be treated with transurethral resection. BCG can be safely used in transplant recipients and likely improves the disease course. Muscle-invasive disease should be treated with radical cystectomy, with special consideration to the dissection and urinary diversion choice. Chemotherapy and immune checkpoint inhibitors can be safely used in regionally advanced bladder cancer with potential benefit. mTOR inhibitors may reduce the risk of developing bladder cancer, and immunosuppression medications should be reduced if malignancy develops.

High Incidence and Early Onset of Urinary Tract Cancers in Patients with BK Polyomavirus Associated Nephropathy

Over-immunosuppressed kidney transplant recipients are susceptible to malignancies and BK polyomavirus (BKPyV)-associated nephropathy (BKPyVAN). This study aimed to verify the association between BKPyV infection and urinary tract cancers (UTC). A total of 244 kidney transplant recipients were enrolled at Chang Gung Memorial Hospital from June 2000 to February 2020. Biopsy-proven BKPyVAN patients (n = 17) had worse kidney function (eGFR: 26 ± 13.7 vs. 47.8 ± 31.0 mL/min/1.73 m²). The 5-year allograft survival rates for patients with and without BKPyVAN were 67% and 93%, respectively (p = 0.0002), while the 10-year patient survival was not different between the two groups. BKPyVAN patients had a significantly higher incidence of UTC compared to the non-BKPyVAN group (29.4% vs. 6.6%). Kaplan-Meier analysis showed that the UTC-free survival rate was significantly lower in BKPyVAN patients, and the onset of UTC was significantly shorter in BKPyVAN patients (53.4 vs. 108.9 months). The multivariate logistic regression analysis demonstrated that age (RR = 1.062) and BKVAN (RR = 6.459) were the most significant risk factors for the development of UTC. Our study demonstrates that BKPyVAN patients have greater allograft losses, higher incidence, a lower cancer-free survival rate, and an earlier onset with a higher relative risk of developing UTC compared to non-BKPyVAN patients.

[Urothelial carcinoma in kidney transplant recipients and candidates: The French guidelines from CTAFU]

OBJECTIVE

To propose surgical recommendations for urothelial carcinoma management in kidney transplant recipients and candidates.

METHOD

A review of the literature (Medline) following a systematic approcah was conducted by the CTAFU regarding the epidemiology, screening, diagnosis and treatment of urothelial carcinoma in kidney transplant recipients and candidates for renal transplantation. References were assessed according to a predefined process to propose recommendations with levels of evidence.

RESULTS

Urothelial carcinomas occur in the renal transplant recipient population with a 3-fold increased incidence as compared with general population. While major risk factors for urothelial carcinomas are similar to those in the general population, aristolochic acid nephropathy and BK virus infection are more frequent risk factors in renal transplant recipients. As compared with general population, NMIBC in the renal transplant recipients are associated with earlier and higher recurrence rate. The safety and efficacy of adjuvant intravesical therapies have been reported in retrospective series. Treatment for localized MIBC in renal transplant recipients is based on radical cystectomy. In the candidate for a kidney transplant with a history of urothelial tumor, it is imperative to perform follow-up cystoscopies according to the recommended frequency, depending on the risk of recurrence and progression of NMIBC and to maintain this follow-up at least every six months up to transplantation whatever the level of risk of recurrence and progression. Based on current data, the present recommendations propose guidelines for waiting period before active wait-listing renal transplant candidates with a history of urothelial carcinoma.

CONCLUSION

The french recommendations from CTAFU should contribute to improve the management of urothelial carcinoma in renal transplant patients and renal transplant candidates by integrating both oncologic objectives and access to transplantation.

Management of de-novo urothelial carcinoma in transplanted patients

PURPOSE OF REVIEW

The aim of this article is to review incidence, risk factors, and optimal management of de-novo urothelial carcinoma in transplant recipients.

RECENT FINDINGS

There is a two to three-fold increased risk for de-novo malignant tumors after solid-organ transplantation, but there is currently no consensus regarding optimal management of de-novo urothelial carcinoma in transplanted patients. Known risk factors include polyomavirus BK, aristolochic acid, and smoking. Data suggest a higher rate of high-grade tumors, as well as predominantly higher stage at primary diagnosis, for both NMIBC and muscle-invasive bladder cancer (MIBC). Treatment for NMIBC includes TURB, mitomycin, and Bacille de Calmette-Guérin instillation with special concern to the immunosuppressive regime. Treatment of MIBC or advanced urothelial carcinoma includes radical cystectomy with chemotherapy if the patient is eligible. A screening should be performed in all transplant recipients, to allow early diagnosis.

SUMMARY

De-novo urothelial carcinoma in transplant recipients is more frequent than in the general population and these tumors were more likely to be high-grade tumors and diagnosed at an advanced stage. There is very little information available on the optimal treatment for these patients. However, aggressive treatment and a strict management according the given recommendations are of the utmost importance.

Reactivation of BK Polyomavirus in Urine Cytology is Not Associated with Urothelial Cell Carcinoma

BK polyomavirus (BKPyV) has been associated with some high-grade and special urothelial cell carcinoma (UCC) subtypes in immunosuppressed patients. Here, we evaluated the relationship of BKPyV-positive urine cytology specimens (UCS) with UCC. A large single-institution database was retrospectively searched for UCS positive for decoy cells, suggesting BKPyV infection. These were tested for the presence of BKPyV by PCR and immunohistochemistry (IHC) in urine sediments and formalin-fixed paraffin-embedded (FFPE) tissue samples of UCC. Decoy cells were reported in 30 patients out of the database with 22.867 UCS. Of these 30 patients, 16 (53.3%) had no history of UCC. Six patients out of these 16 had a history of transplantation, 4 had a history of severe chronic medical conditions, and 6 had no chronic disease. The other fourteen patients were diagnosed with either in situ or invasive UCC of the urinary bladder (14/30; 46.6%) prior to the detection of decoy cells in the urine. Nine of these UCC patients received intravesical treatment (BCG or mitomycin) after the first presentation with UCC. However, the clinical data on the treatment of the other five UCC patients was lacking. IHC identified BKPyV-positivity in the urine samples of non-UCC and UCC patients, while no BKPyV positivity was found in FFPE tissues of primary UCCs and metastases. In addition, BKPyV-PCR results revealed the presence of BKPyV DNA in the urine of the UCC cases, yet none in the UCC tissues itself. These data strongly indicate that BKPyV reactivation is not restricted to immunosuppression. It can be found in UCS of the immunocompetent patients and may be related to the intravesical BCG or mitomycin treatment of the UCC patients.

Total nephroureterocystectomy and urethrectomy due to urothelial carcinoma associated with the BK polyomavirus infection after kidney transplantation: a case report with literature review

Background

BK polyomavirus (BKPyV) infection after kidney transplantation is an important cause of graft failure among kidney transplant recipient and may cause malignant tumor, although the association between BKPyV infection and malignant tumor has been controversial yet.

Case presentation

We report a case of a 39-year-old-male kidney transplantation (KTx) recipient with urine BKPyV replication who developed a graft pelvic tumor with the positive Simian virus 40 large T antigen (SV40 TAg). The patients received a living-related KTx from his 65-year-old mother. A protocol biopsy at 14 months after KTx showed BKPyV-associated nephropathy. Therefore, the dose of immunosuppressants was reduced, resulting in improved BKPyV viremia, but viruria persisted. About 117 months after KTx, urine cytology showed atypical cells suspicious for malignancy. Cystoscopy revealed a tumor on the neck of the bladder. Transurethral resection of the bladder tumor (TUR-BT) was performed; however, the diagnosis of malignancy was not confirmed at that time. Six months after the TUR-BT, urine cytology showed atypical cells definite for malignancy. Computed tomography and retrograde pyelography showed no evidence of urinary tract tumor and metastasis. Subsequently, total nephroureterocystectomy and urethrectomy were performed. Histological examination of the graft ureter revealed a high-grade urothelial carcinoma, with glandular differentiation, pT1. Immunohistochemically, the tumor showed positivities for SV40 TAg and p53, along with increased Ki67 labeling cells were increased. By contrast, nonneoplastic cells were negative for SV40 TAg. At the time of writing the present manuscript, the patient is free from recurrence or residual tumor and being closely monitored without additional therapy, 32 months after the surgery.

Conclusion

The relationship between BKPyV infection after KTx and bladder carcinogenesis remains to be elucidated. However, when the KTx recipients who continue to have BKPyV infection for a long time are treated, the possibility of risk factors for renourinary carcinoma should always be carefully considered.

Application and Pitfalls of Immunohistochemistry in Diagnosis of Challenging Genitourinary Cases

CONTEXT.—

Immunohistochemistry (IHC) has become increasingly important in the evaluation of pathologic conditions in the genitourinary (GU) organs. In addition to careful evaluation of hematoxylin-eosin sections and generation of a differential diagnosis, choosing the optimal panel of IHC markers becomes even more important when the biopsy material is very limited. The following summary of our experience supplemented with relevant literature review exemplifies how to use IHC to facilitate pathologic diagnosis in the GU system.

OBJECTIVE.—

To describe our experience with the most common immunohistochemical markers used in GU pathology.

DATA SOURCES.—

Institutional experience and literature search comprise our data sources.

CONCLUSIONS.—

Application of IHC provides enormous benefits to the interpretation of GU pathologic conditions, including benign and malignant lesions. However, both insufficient and excessive types of use of IHC, as well as incorrect interpretations in common and rare GU conditions, could present pitfalls in diagnosis.

High-grade urothelial carcinoma in a kidney transplant recipient after JC virus nephropathy: The first evidence of JC virus as a potential oncovirus in bladder cancer

Kidney transplant (KT) recipients have an increased risk for urothelial carcinoma. A role for JC virus (JCV) in human cancers is not yet proved but there is an increasingly reported association between BK virus (BKV) nephropathy and renourinary neoplasms. We report a KT recipient who developed a high-grade urothelial carcinoma 5 years after a diagnosis of JCV nephropathy and 9 years after kidney transplantation. Neoplastic tissue was positive for JCV DNA by real-time polymerase chain reaction (PCR). Immunochemical staining showed strong positivity for cell cycle markers (p16, p53, and Ki67) and for early viral protein JCV large T antigen (JCV LTag; using a broad polyomavirus antibody); however, late viral protein (VP1) stained negative. In contrast, in non-neoplastic urothelium, JCV DNA and all immunochemical markers were negative. These facts suggest that malignancy was induced by JCV. To the best of our knowledge, this is the first report of urothelial high-grade carcinoma associated with JCV nephropathy in a KT recipient.

Pathogenicity of BK virus on the urinary system

Introduction

The polyomaviruses are omnipresent in nature. The major sites of BK virus appearance are the kidney tubular epithelial cells and urinary bladder surface transitional cells.

Material and methods

A literature search according to PRISMA guidelines within the Medline database was conducted in July 2019 for articles presenting data about BK virus in urologic aspect without setting time limits, using the terms ‘BK virus’ in conjunction with transplantation, nephropathy, stenosis, cancer, bladder, prostate, kidney.

Results

The BK virus usually stays latent, however, its replication may become active in various clinical situations of impaired immunocompetence such as solid organ transplantation, bone marrow transplantation, AIDS, pregnancy, multiple sclerosis, administration of chemotherapy or biologic therapy. BK virus is associated with two main complications after transplantation: polyomavirus-associated nephropathy in kidney transplant patients and polyomavirus-associated hemorrhagic cystitis in allogeneic hematopoietic stem cell transplant patients.

Conclusions

The aim of this article was to present available data on urologic aspects of BK virus infection, its detection methods and available treatment.

Polyomavirus (BK) cytopathic effect in urine cytology is not associated with high risk of developing high-grade urothelial carcinoma

INTRODUCTION

Polyomavirus cytopathic effect (BK-CPE) is classified as "negative for high-grade urothelial carcinoma" (NHGUC) in the Paris System for Reporting Urinary Cytology. However, polyomaviruses have been historically associated with tumor development and have been recently reported as an independent risk factor for renourinary carcinoma in transplant patients. The aim of the present study was to investigate the relationship between polyomavirus infection in the urinary tract and the subsequent risk of developing high-grade urothelial carcinoma (HGUC) in the general population.

MATERIALS AND METHODS

A retrospective case-control study was conducted to assess BK-CPE in all urinary cytology examinations performed from 2009 to 2011 for cases with an interpretation of NHGUC, NHGUC with BK, atypical urothelial cells (AUCs), or AUCs with BK. The endpoint of the present study was a diagnosis of HGUC on either bladder biopsy or urine cytology for those patients with subsequent follow-up data.

RESULTS

A total of 252 cases with a urinary cytology interpretation of NHGUC, 234 with NHGUC + BK, 255 with AUCs, and 64 with AUCs + BK were identified. The surgical and cytological follow-up data showed that the overall risk of the development of HGUC for those with NHGUC, NHGUC + BK, AUCs, and AUCs + BK was 6.0%, 6.8%, 23.5%, and 12.5%, respectively. No statistically significant differences were found between the patients with NHGUC and those with NHGUC + BK. A statistically significant difference was found for patients with AUCs compared with patients with NHGUC + BK and those with AUCs + BK (P < 0.001).

CONCLUSIONS

The presence of BK-CPE in urine cytology samples does not increase the overall risk of the development of HGUC. Our results support the recommendation from the Paris System for Reporting Urinary Cytology to place urine samples with BK-CPE in the NHGUC category.

Pelvic Surgery in the Transplant Recipient: Important Considerations for the Non-transplant Surgeon

PURPOSE OF REVIEW

Classically, kidney transplantation (KT) consists of heterotopic implantation of the renal graft in the iliac fossa with vascular anastomosis on the iliac vessel and reimplantation of the graft ureter in the bladder of the recipient. However, a wide range of variations exist in both vascular anastomosis and urinary diversion that the non-transplant surgeon should know.

RECENT FINDINGS

For any pelvic surgery in a KT patient, the non-transplant surgeon should preoperatively evaluate the anatomy of the graft, its vascularization and its urinary tract. The transplant ureter should be identified and secured by preoperative JJ stenting whenever needed. For any surgery, maintenance and control of both immunosuppressive treatment and renal function is crucial. The advice or even the assistance of a transplant surgeon should be required because any damage to vascularization or urinary drainage of the renal graft could have dramatic and definitive consequences on graft function.

The case for BK polyomavirus as a cause of bladder cancer

In 2014, the International Agency for Research on Cancer judged Merkel cell polyomavirus (MCPyV) to be a probable human carcinogen. BK polyomavirus (BKPyV, a distant cousin of MCPyV) was ruled a possible carcinogen. In this review, we argue that it has recently become reasonable to view both of these viruses as known human carcinogens. In particular, several complementary lines of evidence support a causal role for BKPyV in the development of bladder carcinomas affecting organ transplant patients. The expansion of inexpensive deep sequencing has opened new approaches to investigating the important question of whether BKPyV causes urinary tract cancers in the general population.

Effect of mechanistic target of rapamycin inhibitors on postrenal transplantation malignancy: A nationwide cohort study

BACKGROUND

Post-transplantation malignancy influenced graft survival and overall survival in the patients receiving renal transplantation. Immunosuppressants influenced the immune surveillance, but whether immunosuppressive agents have impact for incidence of post-transplantation malignancy is still elusive in Taiwan.

METHOD

We conducted a nationwide population-based study. Patients who did not have malignancy history and received kidney transplantation between 2000 and 2010 were enrolled. Specific immunosuppressive users are defined as sustained use (more than 12 months) after renal transplantation. The primary outcome is the development of cancer after kidney transplantation. A Cox proportional hazards model was used to determine the risk of cancer development.

RESULT

Among 4438 recipients, 559 of them were diagnosed with malignancy after 1 year of transplantation. A total of 742 of recipients were as user of mechanistic target of rapamycin (mTOR) inhibitors. The mTOR users had higher rate of receiving pulse therapy. The hazard ratios (HR) for mTOR inhibitor users with exposure more than 5 years for overall malignancy and urothelial malignancy were 0.68 (95% CI: 0.48-0.95, P = 0.02) and 0.60 (95% CI: 0.36-0.99, P = 0.02), respectively. For the overall mortality and reentry of dialysis, the probability of both groups was similar (overall mortality: P = 0.53; reentry of dialysis: P = 0.77).

CONCLUSION

Among the recipients of renal transplantation in Taiwan, mTOR inhibitors with exposure more than 5 years provided a protective role in reducing the risk of overall neoplasm and urothelial malignancy. The probability of reentry of dialysis and overall mortality was similar between the mTORi users and nonusers.

Risk factors associated with post-kidney transplant malignancies: an article from the Cancer-Kidney International Network

In kidney transplant recipients, cancer is one of the leading causes of death with a functioning graft beyond the first year of kidney transplantation, and malignancies account for 8-10% of all deaths in the USA (2.6 deaths/1000 patient-years) and exceed 30% of deaths in Australia (5/1000 patient-years) in kidney transplant recipients. Patient-, transplant- and medication-related factors contribute to the increased cancer risk following kidney transplantation. While it is well established that the overall immunosuppressive dose is associated with an increased risk for cancer following transplantation, the contributive effect of different immunosuppressive agents is not well established. In this review we will discuss the different risk factors for malignancies after kidney transplantation.

Characterization of BK Polyomaviruses from Kidney Transplant Recipients Suggests a Role for APOBEC3 in Driving In-Host Virus Evolution

BK polyomavirus (BKV) frequently causes nephropathy (BKVN) in kidney transplant recipients (KTRs). BKV has also been implicated in the etiology of bladder and kidney cancers. We characterized BKV variants from two KTRs who developed BKVN followed by renal carcinoma. Both patients showed a swarm of BKV sequence variants encoding non-silent mutations in surface loops of the viral major capsid protein. The temporal appearance and disappearance of these mutations highlights the intra-patient evolution of BKV. Some of the observed mutations conferred resistance to antibody-mediated neutralization. The mutations also modified the spectrum of receptor glycans engaged by BKV during host cell entry. Intriguingly, all observed mutations were consistent with DNA damage caused by antiviral APOBEC3 cytosine deaminases. Moreover, APOBEC3 expression was evident upon immunohistochemical analysis of renal biopsies from KTRs. These results provide a snapshot of in-host BKV evolution and suggest that APOBEC3 may drive BKV mutagenesis in vivo.

The Structure of an Infectious Human Polyomavirus and Its Interactions with Cellular Receptors

BK polyomavirus (BKV) causes polyomavirus-associated nephropathy and hemorrhagic cystitis in immunosuppressed patients. These are diseases for which we currently have limited treatment options, but potential therapies could include pre-transplant vaccination with a multivalent BKV vaccine or therapeutics which inhibit capsid assembly or block attachment and entry into target cells. A useful tool in such efforts would be a high-resolution structure of the infectious BKV virion and how this interacts with its full repertoire of cellular receptors. We present the 3.4-Å cryoelectron microscopy structure of native, infectious BKV in complex with the receptor fragment of GT1b ganglioside. We also present structural evidence that BKV can utilize glycosaminoglycans as attachment receptors. This work highlights features that underpin capsid stability and provides a platform for rational design and development of urgently needed pharmacological interventions for BKV-associated diseases.

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Present the cryo-EM structure of native, infectious BKV virion at 3.4 Å resolution

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Reveal interpentamer interactions that mediate capsid assembly

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Determine the interaction of BKV with a receptor fragment of GT1b ganglioside

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Identify possible sites for glycosaminoglycan binding on the virion surface

Urologic malignancies in kidney transplantation

With advances in immunosuppression, graft and patient outcomes after kidney transplantation have improved considerably. As a result, long-term complications of transplantation, such as urologic malignancies, have become increasingly important. Kidney transplant recipients, for example, have a 7-fold risk of renal cell carcinoma (RCC) and 3-fold risk of urothelial carcinoma (UC) compared with the general population. While extrapolation of data from the general population suggest that routine cancer screening in transplant recipients would allow for earlier diagnosis and management of these potentially lethal malignancies, currently there is no consensus for posttransplantation RCC or UC screening as supporting data are limited. Further understanding of risk factors, presentation, optimal management of, and screening for urologic malignancies in kidney transplant patients is warranted, and as such, this review will focus on the incidence, surveillance, and treatment of urologic malignancies in kidney transplant recipients.

Treatment for presumed BK polyomavirus nephropathy and risk of urinary tract cancers among kidney transplant recipients in the United States

Recent case series describe detection of BK polyomavirus (BKV) in urinary tract cancers in kidney transplant recipients, suggesting that BKV could contribute to the development of these cancers. We assessed risk for urinary tract cancers in kidney recipients with or without treatment for presumed BKV nephropathy (tBKVN) using data from the United States Transplant Cancer Match Study (2003-2013). Among 55 697 included recipients, 2015 (3.6%) were reported with tBKVN. Relative to the general population, incidence was similarly elevated (approximately 4.5-fold) for kidney cancer in recipients with or without tBKVN, and incidence was not increased in either group for prostate cancer. In contrast, for invasive bladder cancer, incidence was more strongly elevated in recipients with versus without tBKVN (standardized incidence ratios 4.5 vs. 1.7; N = 48 cases), corresponding to an incidence rate ratio (IRR) of 2.9 (95% confidence interval [CI] 1.0-8.2), adjusted for sex, age, transplant year, and use of polyclonal antibody induction. As a result, recipients with tBKVN had borderline increased incidence for all urothelial cancers combined (renal pelvis, ureter, and bladder cancers: adjusted IRR 2.2, 95% CI 0.9-5.4; N = 89 cases). Together with reports describing BKV detection in tumor tissues, these results support an association between BKV and urothelial carcinogenesis among kidney transplant recipients.

Histological Evolution of BK Virus-Associated Nephropathy: Importance of Integrating Clinical and Pathological Findings

Long-term clinicopathological studies of BK-associated nephropathy (PyVAN) are not available. We studied 206 biopsies (71 patients), followed 3.09 ± 1.46 years after immunosuppression reduction. The biopsy features (% immunostain for PyV large T ag + staining and inflammation ± acute rejection) were correlated with viral load dynamics and serum creatinine to define the clinicopathological status (PyVCPS). Incidence of acute rejection was 28% in the second biopsy and 50% subsequently (25% mixed T cell-mediated allograft rejection (TCMR) + antibody-mediated allograft rejection (AMR); rejection overall affected 38% of patients (>50% AMR). Graft loss was 15.4% (0.8-5.3 years after PyVAN); 76% had complete viral clearance (mean 28 weeks). The only predictors of graft loss were acute rejection (TCMR p = 0.008, any type p = 0.07), and increased "t" and "ci" in the second biopsy (p = 0.006 and 0.048). Higher peak viremia correlated with poorer viral clearance (p = 0.002). Presumptive and proven PyVAN had similar presentation, evolution, and outcome. Late PyVAN (>2 years, 9.8%) justifies BK viremia evaluation at any point with graft dysfunction and/or biopsy evaluation. This study describes the histological evolution of PyVAN and corresponding clinicopathological correlations. Although the pathological features overall reflect the viral and immunological interactions, the PyVAN course remains difficult to predict based on any single feature. Appropriate clinical management requires repeat biopsies and determination of the PyVCPS at relevant time points, for corresponding personalized immunosuppression adjustment.

Cigarette Smoking and Its Hazards in Kidney Transplantation

Cigarette smoking affects many organs. It causes vasoconstriction through activation of sympathetic nervous system which leads to elevation of blood pressure and reduction in glomerular filtration rate and filtration pressure. It also causes thickening of renal arterioles. Cigarette smoking increases the risk of microalbuminuria and accelerates progression of microalbuminuria to macroalbuminuria. Furthermore, it causes rapid loss of glomerular filtration rate in chronic kidney disease patients. After kidney donation, these factors may be injurious to the solitary kidney. Kidney donors with history of cigarette smoking are prone to develop perioperative complications, pneumonia, and wound infection. Postkidney transplantation various stressors including warm and cold ischemia time, delayed graft function, and exposure to calcineurin inhibitors may result in poor graft function. Continuation of cigarette smoking in kidney transplant recipients will add further risk. In this review, we will specifically discuss the effects of cigarette smoking on normal kidneys, live kidney donors, and kidney transplant recipients. This will include adverse effects of cigarette smoking on graft and patient survival, cardiovascular events, rejection, infections, and cancers in kidney transplant recipients. Lastly, the impact of kidney transplantation on behavior and smoking cessation will also be discussed.

Altered Fecal Microbiota Correlates with Liver Biochemistry in Nonobese Patients with Non-alcoholic Fatty Liver Disease

Increasing evidence suggests a role of intestinal dysbiosis in obesity and non-alcoholic fatty liver disease (NAFLD). But it remains unknown in nonobese NAFLD. This prospective, cross-sectional study sought to characterize differences in fecal microbiota between nonobese adult individuals with and without NAFLD and their potential association with metabolic markers of disease progression. A total of 126 nonobese subjects were enrolled: 43 NAFLD and 83 healthy controls (HC). The microbial community was profiled by denaturing gradient gel electrophoresis and examined by 454 pyrosequencing of the 16S ribosomal RNA V3 region. Lower diversity and a phylum-level change in the fecal microbiome were found in NAFLD. Compared with HC, patients had 20% more phylum Bacteroidetes (p = 0.005) and 24% less Firmicutes (p = 0.002). Within Firmicutes, four families and their 8 genera, which were short-chain fatty acids-producing and 7α-dehydroxylating bacteria, were significantly decreased. Moreover, Gram-negative (G-) bacteria were prevalent in NAFLD (p = 0.008). Furthermore, a significant correlation with metabolic markers was revealed for disturbed microbiota in NAFLD. This novel study indicated that intestinal dysbiosis was associated with nonobese NAFLD and might increase the risk of NAFLD progression.