Urothelial cell carcinoma after BK polyomavirus infection in kidney transplant recipients: A cohort study of veterans

BK Polyomavirus-Associated Urothelial Carcinoma of the Bladder with a Background of BK Polyomavirus Nephropathy in a Kidney Transplant Recipient

Renal transplant recipients are at increased risk for the development of a malignant neoplasm. Polyomavirus-associated urothelial carcinoma is a rare tumor that occurs in renal transplant recipients, with approximately 41 cases reported since 2002. It accounts for 27-31% of all post-transplant urothelial carcinomas and develops at an average of 8.5 years after transplantation. Histologically, it shows high-grade urothelial carcinoma (95.1%) with a high frequency of glandular differentiation and micropapillary structures (58.5%) and positive immunohistochemistry for polyomavirus large T antigen, p53 (92.9%), and p16 (100%). We encountered a case of BK polyomavirus (BKPyV)-associated urothelial carcinoma of the bladder diagnosed 54 months after kidney transplantation. Histologically, it was a high-grade urothelial carcinoma with micropapillary features, and immunohistochemically, it was diffusely positive for polyomavirus large T antigen, p16, and p53. BKPyV DNA and mRNA for BKPyV large T antigen have been identified in tissues using real-time polymerase chain reaction. The same sequence of the BKPyV VP1 genome hypervariable region was detected in both transplanted kidney tissue with polyomavirus nephropathy and urothelial carcinoma tissue, suggesting that polyomavirus-associated urothelial carcinoma developed in a background of persistent polyomavirus nephropathy. This case showed typical histological features and was detected and treated at an earlier stage than has been reported. It is important to keep in mind that polyomavirus-associated urothelial carcinoma can develop early after transplantation and might be associated with polyomavirus nephropathy. Because of its rapidly progressive nature, careful follow-up with urine cytology and cystoscopy is necessary. We report this case with a literature review.

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.

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.

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.

Control of Archetype BK Polyomavirus MicroRNA Expression

BK polyomavirus (BKPyV) is a ubiquitous human pathogen, with over 80% of adults worldwide being persistently infected. BKPyV infection is usually asymptomatic in healthy people; however, it causes polyomavirus-associated nephropathy in renal transplant patients and hemorrhagic cystitis in bone marrow transplant patients. BKPyV has a circular, double-stranded DNA genome that is divided genetically into three parts: an early region, a late region, and a noncoding control region (NCCR). The NCCR contains the viral DNA replication origin and cis-acting elements regulating viral early and late gene expression. It was previously shown that a BKPyV microRNA (miRNA) expressed from the late strand regulates viral large-T-antigen expression and limits the replication capacity of archetype BKPyV. A major unanswered question in the field is how expression of the viral miRNA is regulated. Typically, miRNA is expressed from introns in cellular genes, but there is no intron readily apparent in BKPyV from which the miRNA could derive. Here, we provide evidence for primary RNA transcripts that circle the genome more than once and include the NCCR. We identified splice junctions resulting from splicing of primary transcripts circling the genome more than once, and Sanger sequencing of reverse transcription-PCR (RT-PCR) products indicates that there are viral transcripts that circle the genome up to four times. Our data suggest that the miRNA is expressed from an intron spliced out of these greater-than-genome-size primary transcripts.IMPORTANCE The BK polyomavirus (BKPyV) miRNA plays an important role in regulating viral large-T-antigen expression and limiting the replication of archetype BKPyV, suggesting that the miRNA regulates BKPyV persistence. However, how miRNA expression is regulated is poorly understood. Here, we present evidence that the miRNA is expressed from an intron that is generated by RNA polymerase II transcribing the circular viral genome more than once. We identified splice junctions that could be generated only from primary transcripts that contain tandemly repeated copies of the viral genome. The results indicate another way in which viruses optimize expression of their genes using limited coding capacity.

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.

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.

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.

Urothelial carcinoma arising from the transplanted kidney: A single-center experience and literature review

Urothelial carcinoma (UC) is a malignancy predominantly arising in the bladder. Upper tract UC (UUC) is uncommon, accounting only for 5-10% of the cases. High incidence of neoplasms is associated with immunosuppressive therapy; thus, UCs of the transplanted grafts often lead to a more aggressive treatment, in order to withdraw completely the immunosuppression. It significantly affects the patient quality of life, meaning return to dialysis, along with the worse life expectancy. We present our single-institution experience of this rare malignancy in two mid-age kidney transplant recipients, with UCs successfully treated with radical nephroureterectomy: G3 pT3 N0 + G3 pT1 N0 in the first patient and G3 pT2 N0 in the second one. We also review the previous literature focusing on stage of presentation and treatment for the affected kidney transplant patients.

Human polyomaviruses and cancer: an overview

The name of the family Polyomaviridae, derives from the early observation that cells infected with murine polyomavirus induced multiple (poly) tumors (omas) in immunocompromised mice. Subsequent studies showed that many members of this family exhibit the capacity of mediating cell transformation and tumorigenesis in different experimental models. The transformation process mediated by these viruses is driven by viral pleiotropic regulatory proteins called T (tumor) antigens. Similar to other viral oncoproteins T antigens target cellular regulatory factors to favor cell proliferation, immune evasion and downregulation of apoptosis. The first two human polyomaviruses were isolated over 45 years ago. However, recent advances in the DNA sequencing technologies led to the rapid identification of additional twelve new polyomaviruses in different human samples. Many of these viruses establish chronic infections and have been associated with conditions in immunosuppressed individuals, particularly in organ transplant recipients. This has been associated to viral reactivation due to the immunosuppressant therapy applied to these patients. Four polyomaviruses namely, Merkel cell polyomavirus (MCPyV), Trichodysplasia spinulosa polyomavirus (TSPyV), John Cunningham Polyomavirus (JCPyV) and BK polyomavirus (BKPyV) have been associated with the development of specific malignant tumors. However, present evidence only supports the role of MCPyV as a carcinogen to humans. In the present review we present a summarized discussion on the current knowledge concerning the role of MCPyV, TSPyV, JCPyV and BKPyV in human cancers.

BK Virus in Cancer Development

Polyomavirus (PyV) was discovered by accident in 1950 in the course of describing an infectious factor causing multiple tumours in rodents. The term is derived from two Greek words: poly (many) and oma (tumour). At present the family of human polyomaviruses (HPyV) consists of 10 members. One of the first members was BK virus, isolated in 1971 from the urine of a renal transplant patient. Serological examinations have shown that due to its ability to cause latent infection, about 90% of the general population can have specific antibodies attesting infection. In the case of infected persons with normal immunity, this virus is not dangerous. In the impaired immunity, however, loss of immunity results in virus reactivation and development of many life-threatening illnesses. Serological examinations have also reveal that BK polyomavirus considerably affects the development of cancers in humans. Hence, in 2012 a group of 26 researchers from 11 countries associated with the International Agency for Research on Cancer (a part of the World Health Organisation) classified BK polyomavirus within group 2B - “potentially carcinogenic to humans”

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.