Polycystic kidney disease and cancer after renal transplantation

Incidental renal cell carcinoma post bilateral nephrectomy in autosomal dominant polycystic kidney disease

BACKGROUND

Renal cell carcinoma (RCC) is more common in patients with autosomal dominant polycystic kidney disease (ADPKD) than in the general population. Diagnosing RCC in ADPKD is challenging due to the presence of multiple renal cysts, often leading to delays and difficulties in distinguishing RCC from cyst infection or hemorrhage.

AIM

To analyze the prevalence and characterize the clinical features of RCC in patients with ADPKD undergoing simultaneous bilateral native nephrectomy.

METHODS

Between May 2017 and April 2024, 19 ADPKD patients undergoing hemodialysis and awaiting kidney transplantation due to end-stage renal disease (ESRD) underwent bilateral nephrectomies in a single center. Parameters such as patient characteristics, intraoperative blood loss, blood transfusion volume, length of hospital stay, and postoperative complications were documented. Pathological findings for RCC were reviewed.

RESULTS

A total of 38 kidneys were excised from 19 patients, with a mean age of 56.8 years and an average hemodialysis duration of 84.2 months. Eight patients underwent open nephrectomies, and 11 underwent hand-assisted laparoscopic nephrectomies. RCC was detected in 15.8% of kidneys, affecting 21.1% of patients. Two patients had multifocal RCC in both kidneys. All RCC cases were pT1 stage, with the largest lesion averaging 16.5 mm in diameter. The average operative duration was 120 minutes, with intraoperative blood loss averaging 184.2 mL. Five patients required blood transfusions. Postoperative complications occurred in five patients, with a mean hospital stay of 17.1 days. The mean follow-up period was 28.1 months.

CONCLUSION

The prevalence of RCC is higher in patients with ADPKD with ESRD than in those with ESRD alone. Thus, clinicians should be cautious and implement surveillance programs to monitor the development of RCC in patients with ADPKD, particularly those on dialysis.

PKD1 mutant clones within cirrhotic livers inhibit steatohepatitis without promoting cancer

Somatic mutations in non-malignant tissues are selected for because they confer increased clonal fitness. However, it is uncertain whether these clones can benefit organ health. Here, ultra-deep targeted sequencing of 150 liver samples from 30 chronic liver disease patients revealed recurrent somatic mutations. PKD1 mutations were observed in 30% of patients, whereas they were only detected in 1.3% of hepatocellular carcinomas (HCCs). To interrogate tumor suppressor functionality, we perturbed PKD1 in two HCC cell lines and six in vivo models, in some cases showing that PKD1 loss protected against HCC, but in most cases showing no impact. However, Pkd1 haploinsufficiency accelerated regeneration after partial hepatectomy. We tested Pkd1 in fatty liver disease, showing that Pkd1 loss was protective against steatosis and glucose intolerance. Mechanistically, Pkd1 loss selectively increased mTOR signaling without SREBP-1c activation. In summary, PKD1 mutations exert adaptive functionality on the organ level without increasing transformation risk.

Case Report: Autosomal dominant polycystic kidney disease and Wilms' tumor in infancy and childhood

Background

Autosomal dominant polycystic kidney disease (ADPKD) is rare but one of the most common inherited kidney diseases. Normal kidney function is maintained until adulthood in most patients. About 7 in 10 patients with ADPKD develop kidney failure in the latter half of their fifth decade of life. Wilms' tumor, or nephroblastoma, is the most common malignant tumor stemming from kidney cells in the pediatric age group. This type of tumor is the most frequently occurring kidney malignancy in children between the ages of 0 and 5 years. The exact cause of Wilms' tumor is unknown, though about 10% of cases have a genetic predisposition. Wilms' tumor is one of the most successfully treated childhood oncological diseases. Overall, the 5-year survival rates were approximately 90% in both the National Wilms Tumor Study (NWTS) and Paediatric Oncology SIOP studies, showing similar results.

Case presentation

We report a case of a girl diagnosed with autosomal polycystic kidney disease, who subsequently developed Wilms' tumor and underwent successful treatment with chemotherapy. Polycystic kidney disease was suspected in the fetus during prenatal ultrasound and confirmed after birth with ultrasound and genetic testing. The Wilms tumor was an accidental finding during abdominal MRI at the age of 2 years old to rule out liver pathology.

Conclusion

Reports on whether a diagnosis of ADPKD is a risk factor for malignancy are conflicting. In this particular case, Wilms' tumor is present in the background of polycystic kidney disease and was timely diagnosed by an incidental MRI.

The Link between Autosomal Dominant Polycystic Kidney Disease and Chromosomal Instability: Exploring the Relationship

In autosomal dominant polycystic kidney disease (ADPKD) with germline mutations in a PKD1 or PKD2 gene, innumerable cysts develop from tubules, and renal function deteriorates. Second-hit somatic mutations and renal tubular epithelial (RTE) cell death are crucial features of cyst initiation and disease progression. Here, we use established RTE lines and primary ADPKD cells with disease-associated PKD1 mutations to investigate genomic instability and DNA damage responses. We found that ADPKD cells suffer severe chromosome breakage, aneuploidy, heightened susceptibility to DNA damage, and delayed checkpoint activation. Immunohistochemical analyses of human kidneys corroborated observations in cultured cells. DNA damage sensors (ATM/ATR) were activated but did not localize at nuclear sites of damaged DNA and did not properly activate downstream transducers (CHK1/CHK2). ADPKD cells also had the ability to transform, as they achieved high saturation density and formed colonies in soft agar. Our studies indicate that defective DNA damage repair pathways and the somatic mutagenesis they cause contribute fundamentally to the pathogenesis of ADPKD. Acquired mutations may alternatively confer proliferative advantages to the clonally expanded cell populations or lead to apoptosis. Further understanding of the molecular details of aberrant DNA damage responses in ADPKD is ongoing and holds promise for targeted therapies.

Prevalence of Renal Neoplasia in Autosomal Dominant Polycystic Kidney Disease: Systematic Review and Meta-Analysis

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited condition; however, its relationship with renal cell carcinoma (RCC) remains unclear. This paper aims to establish the prevalence of RCC and its subtypes amongst ADPKD patients.

METHODS

A database search was conducted to retrieve studies reporting RCC occurrence within ADPKD patients until July 2023. Key outcomes included number and subtype of RCC cases, and number of RCCs presenting incidentally. A random-effects meta-analysis was performed.

RESULTS

Our search yielded 569 articles, 16 met the inclusion criteria. Nephrectomy specimens from 1,147 ADPKD patients were identified. Of studies reporting per-kidney results (n = 13), 73 RCCs were detected amongst 1,493 kidneys, equating to a per-kidney prevalence of 4.3% (95% CI, 3.1-5.7, I2 = 15.7%). 75 ADPKD patients were found to have RCC (75/1,147), resulting in a per-person prevalence of 5.7% (95% CI, 3.7-7.9, I2 = 40.3%) (n = 16). As 7 patients had bilateral disease, 82 RCCs were detected in total. Of these, 39 were clear cell RCC, 35 were papillary and 8 were other. As such, papillary RCCs made up 41.1% (95% CI, 25.9-56.9, I2 = 18.1%) of detected cancers. The majority of RCCs were detected incidentally (72.5% [95% CI, 43.7-95.1, I2 = 66.9%]).

CONCLUSION

ADPKD appears to be associated with the papillary RCC subtype. The clinical implications of these findings are unclear, however, may become apparent as outcomes and life expectancy amongst APDKD patients improve.

Renal Cell Carcinoma in End-Stage Kidney Disease and the Role of Transplantation

Kidney transplant patients have a higher risk of renal cell carcinoma (RCC) compared to non-transplanted end-stage kidney disease (ESKD) patients. This increased risk has largely been associated with the use of immunosuppression; however, recent genetic research highlights the significance of tissue specificity in cancer driver genes. The implication of tissue specificity becomes more obscure when addressing transplant patients, as two distinct metabolic environments are present within one individual. The oncogenic potential of donor renal tissue is largely unknown but assumed to pose minimal risk to the kidney transplant recipient (KTR). Our review challenges this notion by examining how donor and recipient microenvironments impact a transplant recipient's associated risk of renal cell carcinoma. In doing so, we attempt to encapsulate how ESKD-RCC and KTR-RCC differ in their incidence, pathogenesis, outcome, and approach to management.

Role of standard HLA mismatch in modifying associations between non-pharmacologic risk factors and solid organ malignancy after kidney transplantation

BACKGROUND

Human leukocyte antigen mismatch(es) (HLA-mm) between donors and recipients has not been extensively studied either as a risk factor for solid organ malignancy (SOM) or as a modifier of associations between nonpharmacologic risk factors and SOM in kidney transplant recipients (KTRs).

METHODS

In a secondary analysis from a previous study, 166,256 adult KTRs in 2000-2018 who survived the first 12 months post-transplant free of graft loss or malignancy were classified into 0, 1-3, and 4-6 standard HLA-mm cohorts. Multivariable cause-specific Cox regressions analyzed the risks of SOM and all-cause mortality (ac-mortality) in 5 years following the first KT year. Comparisons of associations between SOM and risk factors in HLA mismatch cohorts were made by estimating the ratios of adjusted hazard ratios.

RESULTS

Compared with 0 HLA-mm, 1-3 HLA-mm was not associated, and 4-6 HLA-mm was equivocally associated with increased risk of SOM [hazard ratio, (HR) = 1.05, 95%, confidence interval (CI) = 0.94-1.17 and HR = 1.11, 95% CI = 1.00-1.34, respectively]. Both 1-3 HLA-mm and 4-6 HLA-mm were associated with increased risk of ac-mortality compared with 0 HLA mm [hazard ratio (HR) = 1.12, 95%, Confidence Interval (CI) = 1.08-1.18) and (HR = 1.16, 95% CI = 1.09-1.22), respectively]. KTR's history of pre-transplant cancer, age 50-64, and >/=65 years were associated with increased risks of SOM and ac-mortality in all HLA mismatch cohorts. Pre-transplant dialysis >2 years, diabetes as the primary renal disease, and expanded or standard criteria deceased donor transplantation were risk factors for SOM in the 0 and 1-3 HLA-mm cohorts and of ac-mortality in all HLA-mm cohorts. KTRs male sex or history of previous kidney transplant was a risk factor for SOM in the 1-3 and 4-6 HLA-mm cohorts and of ac-mortality in all HLA-mm cohorts.

CONCLUSION

Direct association between SOM and the degree of HLA mismatching is equivocal and limited to the 4-6 HLA-mm stratum; however, the degree of HLA mismatching has significant modifying effects on the associations between specific nonpharmacologic risk factors and SOM in KTRs.

Dialysis and Transplant Considerations in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the fourth leading cause of kidney replacement therapy. Unfortunately, the need for dialysis or kidney transplantation is a foreseeable outcome for many patients affected by ADPKD. We review some of the unique issues that should be considered in the management of patients with ADPKD who require dialysis or kidney transplantation. The choice of dialysis modality may be influenced by the enlarged kidneys and liver, but peritoneal dialysis should not be excluded as an option, as studies do not consistently show that there is an increased risk for technique failure or peritonitis. The optimal kidney replacement therapy option remains kidney transplantation; however, nephrectomy may be needed if there is insufficient space for the allograft. Living donor candidates from at-risk families need to be excluded from carrying the disease either by diagnostic imaging criteria or genetic testing. Other potential transplant issues, such as malignancy and cardiovascular and metabolic risks, should also be recognized. Despite these issues, patients with ADPKD requiring dialysis or kidney transplantation generally have more favorable outcomes as compared to those with other causes of chronic kidney disease. Further studies are still needed to personalize the therapeutic approach for those receiving kidney replacement therapy and eventually improve clinical outcomes.

Loss of Pkd1 limits susceptibility to colitis and colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers, with an annual incidence of ~135,000 in the US, associated with ~50,000 deaths. Autosomal dominant polycystic kidney disease (ADPKD), associated with mutations disabling the PKD1 gene, affects as many as 1 in 1000. Intriguingly, some studies have suggested that individuals with germline mutations in PKD1 have reduced incidence of CRC, suggesting a genetic modifier function. Using mouse models, we here establish that loss of Pkd1 greatly reduces CRC incidence and tumor growth induced by loss of the tumor suppressor Apc. Growth of Pkd1-/-;Apc-/- organoids was reduced relative to Apc-/- organoids, indicating a cancer cell-intrinsic activity, even though Pkd1 loss enhanced activity of pro-oncogenic signaling pathways. Notably, Pkd1 loss increased colon barrier function, with Pkd1-deficient animals resistant to DSS-induced colitis, associated with upregulation of claudins that decrease permeability, and reduced T cell infiltration. Notably, Pkd1 loss caused greater sensitivity to activation of CFTR, a tumor suppressor in CRC, paralleling signaling relations in ADPKD. Overall, these data and other data suggest germline and somatic mutations in PKD1 may influence incidence, presentation, and treatment response in human CRC and other pathologies involving the colon.

Cilia and Cancer: From Molecular Genetics to Therapeutic Strategies

Cilia are microtubule-based organelles that project from the cell surface with motility or sensory functions. Primary cilia work as antennae to sense and transduce extracellular signals. Cilia critically control proliferation by mediating cell-extrinsic signals and by regulating cell cycle entry. Recent studies have shown that primary cilia and their associated proteins also function in autophagy and genome stability, which are important players in oncogenesis. Abnormal functions of primary cilia may contribute to oncogenesis. Indeed, defective cilia can either promote or suppress cancers, depending on the cancer-initiating mutation, and the presence or absence of primary cilia is associated with specific cancer types. Together, these findings suggest that primary cilia play important, but distinct roles in different cancer types, opening up a completely new avenue of research to understand the biology and treatment of cancers. In this review, we discuss the roles of primary cilia in promoting or inhibiting oncogenesis based on the known or predicted functions of cilia and cilia-associated proteins in several key processes and related clinical implications.

Simultaneous nephrectomy during kidney transplantation for polycystic kidney disease does not detrimentally impact comorbidity and graft survival

BACKGROUND

The lack of space, as an indication for a native unilateral nephrectomy for positioning a future kidney graft in the absence of other autosomal dominant polycystic kidney disease-related symptoms, remains controversial.

AIM

To evaluate the surgical comorbidity and the impact on graft survival of an associated ipsilateral native nephrectomy during isolated kidney transplantation in patients with autosomal dominant polycystic kidney disease.

METHODS

One hundred and fifty-four kidney transplantations performed between January 2007 and January 2019 of which 77 without (kidney transplant alone (KTA) group) and 77 with associated ipsilateral nephrectomy (KTIN group), were retrospectively reviewed. Demographics and surgical variables were analyzed and their respective impact on surgical comorbidity and graft survival.

RESULTS

Creation of space for future graft positioning was the main reason (n = 74, 96.1%) for associated ipsilateral nephrectomy. No significant difference in surgical comorbidity (lymphocele, wound infection, incisional hernia, wound hematoma, urinary infection, need for blood transfusion, hospitalization stay, Dindo Clavien classification and readmission rate) was observed between the two study groups. The incidence of primary nonfunction and delayed graft function was comparable in both groups [0% and 2.6% (P = 0.497) and 9.1% and 16.9% (P = 0.230), respectively, in the KTA and KTIN group]. The 1- and 5-year graft survival were 94.8% and 90.3%, and 100% and 93.8%, respectively, in the KTA and KTIN group (P = 0.774). The 1- and 5-year patient survival were 96.1% and 92.9%, and 100% and 100%, respectively, in the KTA and KTIN group (P = 0.168).

CONCLUSION

Simultaneous ipsilateral native nephrectomy to create space for graft positioning during kidney transplantation in patients with autosomal dominant polycystic kidney disease does not negatively impact surgical comorbidity and short- and long-term graft survival.

Outcomes of Kidney Transplantation in Patients with Autosomal Dominant Polycystic Kidney Disease: Our Experience Based on 35-Years Follow-Up

Background and objectives: For patients with end-stage renal disease (ESRD), the best replacement therapy is renal transplant (RTx) to ensure life with good quality. Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder and a common cause of ESRD. Different from ESRD of other causes, ADPKD patients need careful pre-RTx evaluations like detecting the presence of intracranial aneurisms, cardiac manifestations, and complications of liver and renal cysts. Materials: We retrieved a total of 1327 RTx patients receiving 1382 times RTx (two recipients with three times, 48 recipients with two times) over the last 35 years. Only 41 of these patients were diagnosed with ADPKD. Results: At the first RTx, patients’ ages were 42.9 ± 12.6 (mean ± SD) years. Ages of the ADPKD group (52.5 ± 10.1 years) were older than the non-ADPKD group (42.7 ± 12.7 years, p = 0.001). We found more cell mediated and antibody mediated rejection (29.3% vs. 26.0%, and 22.0% vs. 7.0%; both p < 0.001), new onset diabetes after transplant (NODAT) (21, 51.2% vs. 326, 25.3%; p = 0.005), and worse graft survival (p < 0.001) in the ADPKD group, and with the development of more malignancies (18; 43.9% vs. 360; 28.0%; p = 0.041). The long-term patient survivals were poorer in the ADPKD group (38.9% vs. 70.3%; p = 0.018). ADPKD was found as an independent risk factor for long-term patient survival (HR = 2.64, 95% CI 1.03−6.76, p = 0.04). Conclusions: Patients with ADPKD-related ESRD developed more NODAT, and also more malignancies if not aggressively surveyed before surgery. Due to poor long-term graft and patient survivals, regular careful examinations for NODAT and malignancies, even in the absence of related symptoms and signs, are highly recommended in the follow-ups.

Polycystic Kidney/Liver Disease

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder that leads to chronic kidney disease and end-stage kidney disease (ESKD). Polycystic liver disease (PCLD) is the most common extrarenal manifestation of ADPKD. Though isolated PCLD and PCLD due to ADPKD are genetically distinct, they follow a similar clinical course of hepatomegaly from multiple cysts with preserved liver function. Tolvaptan use in ADPKD can slow down the deterioration of renal function and growth of cysts. Somatostatin analogs can slow the growth of polycystic livers but the effect is short-lived. The only curative therapy for PCLD is liver transplantation. Renal transplantation can significantly improve survival in patients with ESKD due to ADPKD.

Protein Kinase A Downregulation Delays the Development and Progression of Polycystic Kidney Disease

Background: Upregulation of cAMP-dependent and -independent PKA signaling is thought to promote cystogenesis in polycystic kidney disease (PKD). PKA-I regulatory subunit RIα is increased in kidneys of orthologous mouse models. Kidney-specific knockout of RIα upregulates PKA activity, induces cystic disease in wild-type mice, and aggravates it in Pkd1 ^RC/RC mice. Methods: PKA-I activation or inhibition was compared to EPAC activation or PKA-II inhibition using Pkd1 ^RC/RC metanephric organ cultures. The effect of constitutive PKA (preferentially PKA-I) downregulation in vivo was ascertained by kidney-specific expression of a dominant negative RIαB allele in Pkd1 ^RC/RC mice obtained by crossing Prkar1α ^R1αB/WT, Pkd1 ^RC/RC, and Pkhd1-Cre mice (C57BL/6 background). The effect of pharmacologic PKA inhibition using a novel, selective PRKACA inhibitor (BLU2864) was tested in mIMCD3 3D cultures, metanephric organ cultures, and Pkd1 ^RC/RC mice on a C57BL/6 x 129S6/Sv F1 background. Mice were sacrificed at 16 weeks of age. Results: PKA-I activation promoted and inhibition prevented ex vivo P-Ser133 CREB expression and cystogenesis. EPAC activation or PKA-II inhibition had no or only minor effects. BLU2864 inhibited in vitro mIMCD3 cystogenesis and ex vivo P-Ser133 CREB expression and cystogenesis. Genetic downregulation of PKA activity and BLU2864 directly and/or indirectly inhibited many pro-proliferative pathways and were both protective in vivo BLU2864 had no detectable on- or off-target adverse effects. Conclusions: PKA-I is the main PKA isozyme promoting cystogenesis. Direct PKA inhibition may be an effective strategy to treat PKD and other conditions where PKA signaling is upregulated. By acting directly on PKA, the inhibition may be more effective than or substantially increase the efficacy of treatments that only affect PKA activity by lowering cAMP.

Recurrent thromboses and major vessel compressions in autosomal dominant polycystic kidney disease

A 41-year-old man with autosomal dominant polycystic kidney disease (ADPKD), who had multiple previous unprovoked thrombotic events and without a known coagulopathic disorder, presented with symptomatic extensive thrombus distal to the compression site of the left common iliac vein by a dominant cyst in the left inferior renal pole. This was managed with inferior vena cava filter insertion, left nephrectomy and warfarinization. Later, there was inferior vena cava compression by the right polycystic kidney, leading to elective right nephrectomy. Post-renal transplantation, he had further episodes of partial dialysis access stenosis and extensive thromboses in the left deep and right superficial venous systems of the lower limbs despite absence of extrinsic compression. This represents the first report of recurrent mass effect and thromboembolic events in ADPKD, both before and after nephrectomy and anticoagulation. The potential increased thromboembolic risks among patients with ADPKD warrant further investigation.

Primary Renal Squamous Cell Carcinoma in Native Polycystic Kidney and Ureter 16 Years After Living Donor Kidney Transplant

We describe a case of a 55-year-old woman with polycystic kidney disease who received a living donor kidney transplant 16 years earlier and was on immunosuppressive therapy with satisfactory renal function. The donor was her mother. The patient presented with flank pain on the right side and macrohematuria, and noncontrast computed tomography and magnetic resonance imaging led to the diagnosis of tumors in the remaining right native polycystic kidney and ureter, as well as secondary retroperitoneal dissemination. We performed right radical nephrectomy and ureterectomy with extirpation of 2 metastases; the left native kidney remained intact. Histology showed squamous metaplastic changes and invasive epithelial neoplasm in the lumen of the renal pelvis and ureter with extensive squamous differentiation positive for nuclear p63 as squamous cell immunohistochemical marker. After surgery, an immunosuppressive therapy with methylprednisolone was administered, without calcineurin inhibitors and mycophenolate mofetil. Twelve months later the patient was still alive, with a glomerular filtration rate of 29 mL/min. Needs remain for further treatment modalities in patients with primary squamous cell carcinoma in nonfunctioning kidneys and improvements in imaging technique accuracy.

From kidney injury to kidney cancer

Epidemiologic studies document strong associations between acute or chronic kidney injury and kidney tumors. However, whether these associations are linked by causation, and in which direction, is unclear. Accumulating data from basic and clinical research now shed light on this issue and prompt us to propose a new pathophysiological concept with immanent implications in the management of patients with kidney disease and patients with kidney tumors. As a central paradigm, this review proposes the mechanisms of kidney damage and repair that are active during acute kidney injury but also during persistent injuries in chronic kidney disease as triggers of DNA damage, promoting the expansion of (pre-)malignant cell clones. As renal progenitors have been identified by different studies as the cell of origin for several benign and malignant kidney tumors, we discuss how the different types of kidney tumors relate to renal progenitors at specific sites of injury and to germline or somatic mutations in distinct signaling pathways. We explain how known risk factors for kidney cancer rather represent risk factors for kidney injury as an upstream cause of cancer. Finally, we propose a new role for nephrologists in kidney cancer (i.e., the primary and secondary prevention and treatment of kidney injury to reduce incidence, prevalence, and recurrence of kidney cancer).

Sex differences in cancer risk and outcomes after kidney transplantation

Kidney transplant recipients (KTRs) experience a two- to four-fold increased risk of developing and dying from cancer compared with the general population. High cancer risk results from the interaction of both modifiable and non-modifiable factors. This mapping review explores the impact of sex disparity on cancer's increased incidence and mortality after kidney transplantation (KT). In terms of age, population-based studies indicate that younger recipients of both sexes experience a higher risk of cancer, but this is more pronounced in young women. On the contrary, older men are more likely to be diagnosed with cancer, although their increased risk is not statistically significant compared with the general population. Regarding cancer type, studies show an increased risk of Kaposi sarcoma, gynecologic and lung cancer in women, and bladder and kidney cancer in men. Immune-related cancers such as pos-transplant lymphoproliferative disorders and melanoma are increased in both sexes. Mortality also shows differences between sexes. Although cancer is the second cause of death in both male and female KTRs, studies show higher overall mortality in men and elderly recipients. However, the relative risk of cancer mortality compared with the general population is higher at a younger age, with disparate results regarding sex. Female KTRs appear to die at a younger age than males when compared with the general population. Differences in cancer rates by sex after renal transplantation need further studies. A better understanding of sex-specific differences in cancer epidemiology after KT could help nephrologists to better address pre-transplant counseling, to establish early surveillance programs, and to plan modifiable risk factors such as immunosuppression.

Simultaneous bilateral laparoscopic nephrectomy with kidney transplantation in patients with ESRD due to ADPKD: A single-center experience

Patients with autosomal dominant polycystic disease (ADPKD) may require bilateral nephrectomy (BN) in addition to kidney transplantation (KT) for symptom control. This study aims to compare simultaneous BNKT to contemporaneous controls by reviewing our cohort of ADPKD patients who underwent KT from a living donor from January 2014 to October 2019. Symptomatic patients who underwent laparoscopic BNKT were compared to KT alone. Clinical differences related to undertaking bilateral nephrectomies showed increased total kidney volumes (P < .001). We assessed operative parameters, complications, and clinical outcomes. The complications were classified according to the Clavien-Dindo system. In 148 transplant recipients, 51 underwent BNKT, and 97 KT alone. There was no difference in baseline demographics. BNKT recipients had longer cold ischemia time, required more ICU care, increased blood transfusions and longer hospital stays. The kidney function was similar in the first year in both groups, with no difference in delayed graft function, readmissions or severe grade III and IV complications within 3 months after surgery. Laparoscopic BNKT is safe and feasible at the time of living donor KT. Although higher acuity care is needed with a longer initial hospital stay, there are comparable posttransplant patient and allograft outcomes.

Ciclopirox olamine induces ferritinophagy and reduces cyst burden in polycystic kidney disease

Despite the recent launch of tolvaptan, the search for safer polycystic kidney disease (PKD) drugs continues. Ciclopirox (CPX) or its olamine salt (CPX-O) is contained in a number of commercially available antifungal agents. CPX is also reported to possess anticancer activity. Several mechanisms of action have been proposed, including chelation of iron and inhibition of iron-dependent enzymes. Here, we show that CPX-O inhibited in vitro cystogenesis of primary human PKD cyst-lining epithelial cells cultured in a 3D collagen matrix. To assess the in vivo role of CPX-O, we treated PKD mice with CPX-O. CPX-O reduced the kidney-to-body weight ratios of PKD mice. The CPX-O treatment was also associated with decreased cell proliferation, decreased cystic area, and improved renal function. Ferritin levels were markedly elevated in cystic kidneys of PKD mice, and CPX-O treatment reduced renal ferritin levels. The reduction in ferritin was associated with increased ferritinophagy marker nuclear receptor coactivator 4, which reversed upon CPX-O treatment in PKD mice. Interestingly, these effects on ferritin appeared independent of iron. These data suggest that CPX-O can induce ferritin degradation via ferritinophagy, which is associated with decreased cyst growth progression in PKD mice. Most importantly these data indicate that CPX-O has the potential to treat autosomal dominant PKD.

Serum microRNA profiles in patients with autosomal dominant polycystic kidney disease show systematic dysregulation partially reversible by hemodialysis

INTRODUCTION

The impact of autosomal dominant polycystic kidney disease (ADPKD) on serum microRNAs (miRNA) is unknown.

MATERIAL AND METHODS

For profiling experiment we recruited 30 patients from three equinumerous groups: controls, ADPKD and ADPKD on hemodialysis. From the last group extra samples were collected for in pre-/postdialysis analysis. Additionally, 23 healthy volunteers were used for selected biomarker verification. Real-time PCR arrays were used for quantification of 752 miRNAs. Validation of selected miRNAs was performed in total RNA extracted from the serum and the exosomal fraction in pre-/postdialysis samples.

RESULTS

In total, 37 significant circulating miRNAs were found to differ between ADPKD patients and controls. In validation, 3 miRNAs with the highest fold change in comparison of dialyzed vs non-dialyzed patients (miR-532-3p, miR-320b, miR-144-5p) were not significantly altered by hemodialysis and from the top down-regulated ones, miR-27a-3p was significantly lower after dialysis in both total and exosomal fractions, miR-20a-5p was down-regulated in the exosomal fraction and miR-16-5p was unaltered by hemodialysis. MiR-16-5p was selected as the best circulating biomarker of ADPKD. Circulating representatives of the miR-17 family sharing the same seed region (miR-20a-5p, miR-93-5p and miR-106a-5p) showed significantly lower expression among dialyzed vs. non-dialyzed patients and their exosomal fraction dropped after hemodialysis.

CONCLUSIONS

The serum miRNAs among ADPKD patients differ substantially depending on the stage of CKD. The exosomal fraction of miRNA was more affected by dialysis than the total one. There was a common pattern of down-regulation for circulating miR-17 family members sharing the same seed region.

Sarcomatoid renal cell carcinoma with autosomal dominant polycystic kidney disease: a case report and literature review

Diagnosis of renal cell carcinoma (RCC) in patients with autosomal dominant polycystic kidney disease (ADPKD) is challenging and often delayed due to accompanying multiple renal cysts. Sometimes, it is difficult to distinguish RCC from cyst infection or hemorrhage. We herein present the case of a patient with ADPKD undergoing long-term hemodialysis whose sarcomatoid RCC was difficult to diagnose and was confirmed via nephrectomy. A 53-year-old male, undergoing hemodialysis since 20 years for end-stage renal disease secondary to ADPKD, was admitted to our hospital with a 3-week history of fever at > 38 °C and right flank pain. Clinical manifestations were compatible with cyst infection. Magnetic resonance images of the lesion identified in the lower right kidney, revealing slightly high signal intensity on T1-weighted images, low signal intensity on T2 weighted images, and restricted diffusion on diffusion-weighted images, were also consistent with those of cyst infection. Therefore, antibiotic therapy with ciprofloxacin, doripenem, and vancomycin was initiated. However, the patient's symptoms did not improve. Consequently, right nephrectomy was performed for both diagnosis and treatment, which revealed a sarcomatoid RCC with metastasis to the regional lymph node. The patient gradually developed cachexia and died on day 106 post-admission. The present case illustrates the difficulty of diagnosing RCC in patients with ADPKD, particularly sarcomatoid RCC, which is a rare and aggressive variant of RCC, even with the use of various types of imaging modalities. An early decision of nephrectomy may be necessary in such cases.

Novel non-cystic features of polycystic kidney disease: having new eyes or seeking new landscapes

For decades, researchers have been trying to decipher the complex pathophysiology of autosomal dominant polycystic kidney disease (ADPKD). So far these efforts have led to clinical trials with different candidate treatments, with tolvaptan being the only molecule that has gained approval for this indication. As end-stage kidney disease due to ADPKD has a substantial impact on health expenditures worldwide, it is likely that new drugs targeting kidney function will be developed. On the other hand, recent clinical observations and experimental data, including PKD knockout models in various cell types, have revealed unexpected involvement of many other organs and cell systems of variable severity. These novel non-cystic features, some of which, such as lymphopenia and an increased risk to develop infections, should be validated or further explored and might open new avenues for better risk stratification and a more tailored approach. New insights into the aberrant pathways involved with abnormal expression of PKD gene products polycystin-1 and -2 could, for instance, lead to a more directed approach towards early-onset endothelial dysfunction and subsequent cardiovascular disease. Furthermore, a better understanding of cellular pathways in PKD that can explain the propensity to develop certain types of cancer can guide post-transplant immunosuppressive and prophylactic strategies. In the following review article we will systematically discuss recently discovered non-cystic features of PKD and not well-established characteristics. Overall, this knowledge could enable us to improve the outcome of PKD patients apart from ongoing efforts to slow down cyst growth and attenuate kidney function decline.

The master regulators Myc and p53 cellular signaling and functions in polycystic kidney disease

The transcription factors Myc and p53 associated with oncogenesis play determinant roles in a human genetic disorder, autosomal dominant polycystic kidney disease (ADPKD), that was coined early in ADPKD etiology a «neoplasia in disguise ». These factors are interdependent master cell regulators of major biological processes including proliferation, apoptosis, cell growth, metabolism, inflammation, fibrosis and differentiation that are all modulated in ADPKD. Myc and p53 proteins evolved to respond and carry out overlapping functions via opposing mechanisms of action. Studies in human ADPKD kidneys, caused by mutations in the PKD1 or PKD2 genes, reveal reduced p53 expression and high expression of Myc in the cystic tubular epithelium. Myc and p53 via direct interaction act respectively, as transcriptional activator and repressor of PKD1 gene expression, consistent with increased renal PKD1 levels in ADPKD. Mouse models generated by Pkd1 and Pkd2 gene dosage dysregulation reproduce renal cystogenesis with activation of Myc expression and numerous signaling pathways, strikingly similar to those determined in human ADPKD. In fact, upregulation of renal Myc expression is also detected in virtually all non-orthologous animal models of PKD. A definitive causal connection of Myc with cystogenesis was established by renal overexpression of Myc in transgenic mice that phenocopies human ADPKD. The network of activated signaling pathways in human and mouse cystogenesis individually or in combination can target Myc as a central node of PKD pathogenesis. One or many of the multiple functions of Myc upon activation can play a role in every phases of ADPKD development and lend credence to the notion of "Myc addiction" for cystogenesis. We propose that the residual p53 levels are conducive to an ADPKD biological program without cancerogenesis while a "p53 dependent annihilation" mechanism would be permissive to oncogenesis. Of major importance, Myc ablation in orthologous mouse models or direct inhibition in non-orthologous mouse model significantly delays cystogenesis consistent with pharmacologic or genetic inhibition of Myc upstream regulator or downstream targets in the mouse. Together, these studies on PKD proteins upon dysregulation not only converged on Myc as a focal point but also attribute to Myc upregulation a causal and « driver » role in pathogenesis. This review will present and discuss our current knowledge on Myc and p53, focused on PKD mouse models and ADPKD.

Metabolic reprogramming and the role of mitochondria in polycystic kidney disease

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a slowly progressive disease characterized by the relentless growth of renal cysts throughout the life of affected individuals. Early evidence suggested that the epithelia lining the cysts share neoplastic features, leading to the definition of PKD as a "neoplasm in disguise". Recent work from our and other laboratories has identified a profound metabolic reprogramming in PKD, similar to the one reported in cancer and consistent with the reported increased proliferation. Multiple lines of evidence suggest that aerobic glycolysis (a Warburg-like effect) is present in the disease, along with other metabolic dysfunctions such as an increase in the pentose phosphate pathway, in glutamine anaplerosis and fatty acid biosynthesis, while fatty acid oxidation and oxidative phosphorylation (OXPHOS) are decreased. In addition to glutamine, other amino acid-related pathways appear altered, including asparagine and arginine. The precise origin of the metabolic alterations is not entirely clear, but two hypotheses can be formulated, not mutually exclusive. First, the polycystins have been recently shown to regulate directly mitochondrial function and structure either by regulating Ca²⁺ uptake in mitochondria at the Mitochondria Associated Membranes (MAMs) of the Endoplasmic Reticulum, or by a direct translocation of a small fragment of the protein into the matrix of mitochondria. One alternative possibility is that metabolic and mitochondrial dysfunctions in ADPKD are secondary to the de-regulation of proliferation, driven by the multiple signaling pathways identified in the disease, which include mTORC1 and AMPK among the most relevant. While the precise mechanisms underlying these novel alterations identified in ADPKD will need further investigation, it is evident that they offer a great opportunity for novel interventions in the disease.

The role of DNA damage as a therapeutic target in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic kidney disease and is caused by heterozygous germ-line mutations in either PKD1 (85%) or PKD2 (15%). It is characterised by the formation of numerous fluid-filled renal cysts and leads to adult-onset kidney failure in ~50% of patients by 60 years. Kidney cysts in ADPKD are focal and sporadic, arising from the clonal proliferation of collecting-duct principal cells, but in only 1-2% of nephrons for reasons that are not clear. Previous studies have demonstrated that further postnatal reductions in PKD1 (or PKD2) dose are required for kidney cyst formation, but the exact triggering factors are not clear. A growing body of evidence suggests that DNA damage, and activation of the DNA damage response pathway, are altered in ciliopathies. The aims of this review are to: (i) analyse the evidence linking DNA damage and renal cyst formation in ADPKD; (ii) evaluate the advantages and disadvantages of biomarkers to assess DNA damage in ADPKD and finally, (iii) evaluate the potential effects of current clinical treatments on modifying DNA damage in ADPKD. These studies will address the significance of DNA damage and may lead to a new therapeutic approach in ADPKD.

Metformin induces lipid changes on sphingolipid species and oxidized lipids in polycystic ovary syndrome women

Metformin is one of the treatments used for PCOS pathology decreasing body weight, plasma androgen, FSH and glucose levels. Unfortunately, there is little known about metformin's effects on lipid metabolism, a crucial process in PCOS pathology. We have employed a lipidomic approach to explore alterations in the plasma lipid profile of patients with PCOS following metformin treatment. The aim is to offer new insights about the effect of metformin in PCOS patients. Plasma samples were obtained from 27 subjects prior to and following 12 weeks of metformin treatment. A detailed biochemical characterization and lipidomic profile was performed. Metformin reduces BMI, HOMA-IR, FSH and androstenedione and increases DHEA-S but no changes were found in glucose levels after treatment. Multivariate statistics revealed a specific lipidomic signature due to the effect of 12 weeks of metformin treatment in PCOS patients. This signature includes changes in sphingolipid metabolism suggesting a crosstalk between these lipid species and the androgenic metabolism and a decrease in oxidized lipids reinforcing that metformin treatment improves oxidative stress status. Our study confirms the specific effect of metformin in lipid metabolism on women with PCOS after 12 weeks of treatment.

Cancer in kidney transplant recipients

Cancer is the second most common cause of mortality and morbidity in kidney transplant recipients after cardiovascular disease. Kidney transplant recipients have at least a twofold higher risk of developing or dying from cancer than the general population. The increased risk of de novo and recurrent cancer in transplant recipients is multifactorial and attributed to oncogenic viruses, immunosuppression and altered T cell immunity. Transplant candidates and potential donors should be screened for cancer as part of the assessment process. For potential recipients with a prior history of cancer, waiting periods of 2-5 years after remission - largely depending on the cancer type and stage of initial cancer diagnosis - are recommended. Post-transplantation cancer screening needs to be tailored to the individual patient, considering the cancer risk of the individual, comorbidities, overall prognosis and the screening preferences of the patient. In kidney transplant recipients diagnosed with cancer, treatment includes conventional approaches, such as radiotherapy and chemotherapy, together with consideration of altering immunosuppression. As the benefits of transplantation compared with dialysis in potential transplant candidates with a history of cancer have not been assessed, current clinical practice relies on evidence from observational studies and registry analyses.

[Arterial embolization of polycystic kidneys as an alternative to ergonomic nephrectomy in renal pre-transplantation. Monocentric retrospective study]

PURPOSE

This study aims at providing a retrospective assessment of the decrease in renal volume after renal artery embolization (RAE) among a group of patients with autosomal dominant polycystic renal disease and for whom transplantation, for ergonomic reasons was temporarily advised against.

MATERIAL AND METHODS

Between November 2014 and March 2017, as part of pre-transplantory procedure 15 patients, including 11 men and 4 women benfited from renal embolization (RAE) in a context of preparation for transplant in Lille University Hospital. All of the patients were suffering from autosomal dominant polycystic renal disease (ADPKD) at a severe or terminal stage of renal disease.

RESULTS

The original mean total kidney volume (TKV) was 2550.6 cm³±1771 (1102 cm³; 7310 cm³), the average TKV at 3 months was 1684 cm³±1539 (648 cm³; 6930 cm³) with an average decrease of 33% in the volume (5.2%; 83.9%) (95% confidence interval [0.229-0.436]) (P<0.01) and 1632±1743 (599 cm³; 6758 cm³) at 6 months with an average decrease of 40.7% (7.6%; 64.1%) (IC95% 0.306-0.508) (P<0.01). Among the 15 patients, 13 had their contraindication removed and to date 7 have had successful transplants. One failure due to a very high initial volume (7310cm³) required a secondary nephrectomy. No post-embolization syndrome has been noticed, 2 minor complications occurred (13%) involving a difficult resumption of transit and there was one case of hematuria.

CONCLUSION

ERA procedures must have a place in the ergonomic transplant strategy of patients with ADPKD with a low complication rate and a high efficiency. Nephrectomy indications before transplantation must therefore be reconsidered due to a major postoperative risk. Our results are in line with larger scale studies. Nevertheless, these results need to be confirmed by a large-scale randomized prospective study.

LEVEL OF EVIDENCE

4.

Is polycystic kidney disease associated with malignancy in children?

Background

Polycystic kidney disease (PKD) is an inherited condition characterized by progressive development of end‐stage renal disease, hypertension, hepatic fibrosis, and cysts in the kidney, liver, pancreas, spleen, thyroid, and epididymis. While malignancies have been reported in association with PKD in adults, the incidence of malignancies in children with PKD is not currently known.

Methods

We report on five patients with a known history of PKD who developed a malignancy as children at the University of California, Los Angeles and the University of Colorado Anschutz Medical Campus. Patients were included from 2012 to 2017.

Results

We present five patients with a history of PKD diagnosed with a malignancy during childhood without any additional known mutations to suggest a genetic predisposition to develop cancer. This includes the first reported case of hepatocellular carcinoma in a patient with autosomal recessive polycystic kidney disease.

Conclusion

Our report illustrates the potential that PKD may be associated with an increased risk for developing cancer, even in children. Further research is necessary to better understand this relationship.

Bilateral Nephrectomy for Adult Polycystic Kidney Disease Does Not Affect the Graft Function of Transplant Patients and Does Not Result in Sensitisation

BACKGROUND

Native nephrectomy in Adult Polycystic Kidney Disease (ADPKD) patients is a major operation with controversy related to timing and indications. We present our single centre experience in transplanted patients and future candidates for transplantation.

METHODS

Retrospective analysis from an anonymised database of bilateral nephrectomies for ADPKD patients. Results were reported as median, range, and percentage. Differences between groups were tested using ANOVA and t-test. Surgery was performed between January 2012 and July 2018.

RESULTS

Thirty-three patients underwent bilateral native nephrectomy for APKD. 18 had a functioning kidney transplant (transplant group, 55%) while 15 patients were on dialysis (dialysis group, 45%) at the time of surgery; 8 patients of the latter group (24% of the whole cohort) were eventually transplanted. 53% were males, with median age of 55 years (27-71). Indications to surgery were the following: space (symptoms related to the size of the native kidneys or need to create space for transplantation) (59%), recurrent cyst infection (36%), haematuria (15%), pain (24%), and weight loss associated with cystic alteration on imaging (3%). In the transplant group, postoperative kidney function was not affected; haemoglobin serum levels significantly dropped in the whole cohort: 121 (82-150) g/L, versus 108 (58-154) g/L (p<0.001), with 14 patients being transfused perioperatively. Elevation of anti-HLA antibodies was noted in one female patient on dialysis, with no change in DSA levels and no rejection after transplant for all 26 transplanted patients. Median postoperative length of hospital stay was 9 days (6-71). One patient died (3%) after six months. Median follow-up for the whole cohort was 282 days (13-1834). Histopathological examination revealed incidental renal neoplasms in five cases (15%): 1 pT1a papillary renal cell carcinoma and 4 papillary adenomas.

CONCLUSIONS

Native nephrectomy for ADPKD could be safely performed in case of refractory symptoms, suspect of cancer or to create space for transplantation. It does not affect graft function or DSA status of transplanted patients or the prospect of transplantation of those on the waiting list.

Gender differences in cancer risk after kidney transplantation

Kidney transplant (KT) recipients are at greater risk of developing some cancers than the general population. Moreover, cancer is the only cause of death that is currently increasing after kidney transplantation. We analyzed incidence, risk factors and characteristics of post-transplant malignancies (solid organ tumors and lymphoproliferative disorders) at our center in 925 KT recipients (1979-2014). Sex differences were particularly assessed. One hundred and eight patients (11.7%) developed solid organ tumors (76.9%) or lymphoma (23.1%). Twenty-one percent of patients who reached 20 years after KT developed cancer, with a median post-KT time to diagnosis of 7.4 years. Most common solid organs affected were lung (30.1%), prostate (10.8%), bladder (9.6%), and native kidney (7.2%). When analyzing standardized incidence ratios (SIR) by gender compared to the general population, relative risk was increased in women (SIR = 1.81; 95%CI, 1.28-2.45) but not significantly increased in men (SIR = 1.22; 0.95-2.52). Regarding specific types, gynecological (SIR = 11.6; 4.2-22.7) and lung (SIR = 10.0; 4.3-18.2) in women, and bladder (SIR = 16.3; 5.9-32.1) in men were the most affected locations. Thymoglobulin, a polyclonal antibody that has been used as an immunosuppressive agent in kidney transplantation over the last decades, was a significant risk factor for developing cancer in adjusted regression analysis [IRR = 1.62, 1.02-2.57; p = 0.041], and was associated with lower patient survival. Compared with the general population, the incidence of post-KT non-skin cancer is almost two-fold higher in women but not significantly higher in men. Lung is the most common solid organ affected. Thymoglobulin induction therapy is associated with a greater risk.

Somatic Mutations in Renal Cyst Epithelium in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a ciliopathy caused by mutations in PKD1 and PKD2 that is characterized by renal tubular epithelial cell proliferation and progressive CKD. Although the molecular mechanisms involved in cystogenesis are not established, concurrent inactivating constitutional and somatic mutations in ADPKD genes in cyst epithelium have been proposed as a cellular recessive mechanism.

METHODS

We characterized, by whole-exome sequencing (WES) and long-range PCR techniques, the somatic mutations in PKD1 and PKD2 genes in renal epithelial cells from 83 kidney cysts obtained from nine patients with ADPKD, for whom a constitutional mutation in PKD1 or PKD2 was identified.

RESULTS

Complete sequencing data by long-range PCR and WES was available for 63 and 65 cysts, respectively. Private somatic mutations of PKD1 or PKD2 were identified in all patients and in 90% of the cysts analyzed; 90% of these mutations were truncating, splice site, or in-frame variations predicted to be pathogenic mutations. No trans-heterozygous mutations of PKD1 or PKD2 genes were identified. Copy number changes of PKD1 ranging from 151 bp to 28 kb were observed in 12% of the cysts. WES also identified significant mutations in 53 non-PKD1/2 genes, including other ciliopathy genes and cancer-related genes.

CONCLUSIONS

These findings support a cellular recessive mechanism for cyst formation in ADPKD caused primarily by inactivating constitutional and somatic mutations of PKD1 or PKD2 in kidney cyst epithelium. The potential interactions of these genes with other ciliopathy- and cancer-related genes to influence ADPKD severity merits further evaluation.

Renal Cell Carcinoma in Renal Transplantation: The Case for Surveillance

INTRODUCTION

Between January 2013 and September 2015, 135 consecutive renal transplant patients were screened prospectively with ultrasound for renal cell carcinoma (RCC).

RESULTS

Eighteen ultrasound abnormalities were identified with 4 solid lesions detected. Fifty-six other patients were screened retrospectively by referring nephrology groups, with 6 additional malignancies found.

CONCLUSION

As a result of our data, we recommend and have instituted annual ultrasound screening of native kidneys in all renal transplant patients.

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.

Comprehensive Review on Colorectal Cancer and Transplant

Colorectal cancer (CRC) is a common malignancy worldwide. Some studies suggest that organ recipients are at a higher risk for CRC than the general population. The underlying transplant indications and their inherent risk factors for CRC may drive the variation in incidence rates that are seen in patients receiving different allografts. Recipients with cystic fibrosis are now recognized as a population at high risk for CRC at a young age. Transplant recipients have high mortality following a CRC diagnosis, even if it is detected at an early stage. Certain types of immunosuppression have been shown to accelerate cancer transformation and may contribute to the more aggressive phenotype seen in organ recipients. Given the high incidence and progressive nature of posttransplant CRC, shorter screening intervals with a modality that can detect early-stage polyps may be essential to prevent mortality. Future research is needed to better elucidate the role of immunosuppression in carcinogenesis. This comprehensive review examines CRC risk, screening, and management specific to organ transplant candidates and recipients.

Renal Cancer in Recipients of Kidney Transplant

The aim of our study is to determine characteristics and outcomes of kidney cancer in renal transplant recipients. MEDLINE® database was searched in June 2015 to identify cases of kidney cancer in renal transplant recipients. We include also a new case. Descriptive statistics were used for analysis. Forty-eight (48) recipients reported in 25 papers met the eligibility criteria. The median age was 47 years (range 9-66); 27% were females. Chronic glomerulonephritis, cystic kidney disease and hypertension were common indications for renal transplant. Among donors 24% were females and the median age was 52.5 years (17-73); 62% of kidney cancers were donor-derived. The median interval between transplant and cancer diagnosis was shorter for cancer of recipient versus donor origin (150 vs. 210 days). Clear cell carcinoma was diagnosed in 17%. 25% had metastasis at diagnosis. Kidney explantation or excision was done in 90% and 84% of cases with and without metastasis respectively. The median survival was 72 months. Actuarial 1-year and 5-year survival rates were 73.4% and 55.1% respectively. Among the recipients from 7 donors who subsequently developed malignancy, 57% were dead within a year. Kidney transplant recipients have a small risk of kidney cancer, which affects younger patients and occurs within a year of transplant, likely due to immunosuppression. Whether the use of older donors may increase the likelihood needs further investigation. The presence of metastasis, explantation or excision of affected kidney and development of cancer in donors predict outcomes. The results may guide patient education and informed decision-making.

Risk of Renal Cell Carcinoma Among Kidney Transplant Recipients in the United States

Renal cell carcinoma (RCC) is a common malignancy following kidney transplantation. We describe RCC risk and examine RCC risk factors among US kidney recipients (1987-2010). The Transplant Cancer Match Study links the US transplant registry with 15 cancer registries. Standardized incidence ratios (SIRs) were used to compare RCC risk (overall and for clear cell [ccRCC] and papillary subtypes) to the general population. Associations with risk factors were assessed using Cox models. We identified 683 RCCs among 116 208 kidney recipients. RCC risk was substantially elevated compared with the general population (SIR 5.68, 95% confidence interval 5.27-6.13), especially for papillary RCC (SIR 13.3 versus 3.98 for ccRCC). Among kidney recipients, RCC risk was significantly elevated for blacks compared to whites (hazard ratio [HR] 1.50) and lower in females than males (HR 0.56). RCC risk increased with prolonged dialysis preceding transplantation (p-trend < 0.0001). Risk was variably associated for RCC subtypes with some medical conditions that were indications for transplantation: ccRCC risk was reduced with polycystic kidney disease (HR 0.54), and papillary RCC was increased with hypertensive nephrosclerosis (HR 2.02) and vascular diseases (HR 1.86). In conclusion, kidney recipients experience substantially elevated risk of RCC, especially for papillary RCC, and multiple factors contribute to these cancers.

Independent Pre-Transplant Recipient Cancer Risk Factors after Kidney Transplantation and the Utility of G-Chart Analysis for Clinical Process Control

Background

The aim of this study is to identify independent pre-transplant cancer risk factors after kidney transplantation and to assess the utility of G-chart analysis for clinical process control. This may contribute to the improvement of cancer surveillance processes in individual transplant centers.

Patients and Methods

1655 patients after kidney transplantation at our institution with a total of 9,425 person-years of follow-up were compared retrospectively to the general German population using site-specific standardized-incidence-ratios (SIRs) of observed malignancies. Risk-adjusted multivariable Cox regression was used to identify independent pre-transplant cancer risk factors. G-chart analysis was applied to determine relevant differences in the frequency of cancer occurrences.

Results

Cancer incidence rates were almost three times higher as compared to the matched general population (SIR = 2.75; 95%-CI: 2.33–3.21). Significantly increased SIRs were observed for renal cell carcinoma (SIR = 22.46), post-transplant lymphoproliferative disorder (SIR = 8.36), prostate cancer (SIR = 2.22), bladder cancer (SIR = 3.24), thyroid cancer (SIR = 10.13) and melanoma (SIR = 3.08). Independent pre-transplant risk factors for cancer-free survival were age <52.3 years (p = 0.007, Hazard ratio (HR): 0.82), age >62.6 years (p = 0.001, HR: 1.29), polycystic kidney disease other than autosomal dominant polycystic kidney disease (ADPKD) (p = 0.001, HR: 0.68), high body mass index in kg/m² (p<0.001, HR: 1.04), ADPKD (p = 0.008, HR: 1.26) and diabetic nephropathy (p = 0.004, HR = 1.51). G-chart analysis identified relevant changes in the detection rates of cancer during aftercare with no significant relation to identified risk factors for cancer-free survival (p<0.05).

Conclusions

Risk-adapted cancer surveillance combined with prospective G-chart analysis likely improves cancer surveillance schemes by adapting processes to identified risk factors and by using G-chart alarm signals to trigger Kaizen events and audits for root-cause analysis of relevant detection rate changes. Further, comparative G-chart analysis would enable benchmarking of cancer surveillance processes between centers.

Ciliogenesis and the DNA damage response: a stressful relationship

Both inherited and sporadic mutations can give rise to a plethora of human diseases. Through myriad diverse cellular processes, sporadic mutations can arise through a failure to accurately replicate the genetic code or by inaccurate separation of duplicated chromosomes into daughter cells. The human genome has therefore evolved to encode a large number of proteins that work together with regulators of the cell cycle to ensure that it remains error-free. This is collectively known as the DNA damage response (DDR), and genome stability mechanisms involve a complex network of signalling and processing factors that ensure redundancy and adaptability of these systems. The importance of genome stability mechanisms is best illustrated by the dramatic increased risk of cancer in individuals with underlying disruption to genome maintenance mechanisms. Cilia are microtubule-based sensory organelles present on most vertebrate cells, where they facilitate transduction of external signals into the cell. When not embedded within the specialised ciliary membrane, components of the primary cilium's basal body help form the microtubule organising centre that controls cellular trafficking and the mitotic segregation of chromosomes. Ciliopathies are a collection of diseases associated with functional disruption to cilia function through a variety of different mechanisms. Ciliopathy phenotypes can vary widely, and although some cellular overgrowth phenotypes are prevalent in a subset of ciliopathies, an increased risk of cancer is not noted as a clinical feature. However, recent studies have identified surprising genetic and functional links between cilia-associated proteins and genome maintenance factors. The purpose of this mini-review is to therefore highlight some of these discoveries and discuss their implications with regards to functional crosstalk between the DDR and ciliogenesis pathways, and how this may impact on the development of human disease.

Risk of cancer in retransplants compared to primary kidney transplants in the United States

Recipients of kidney transplantation have elevated risk of developing cancer. There are limited data on cancer risk in recipients of kidney retransplantation. We used data from the Transplant Cancer Match Study, which links the U.S. transplant registry with 15 cancer registries. Cancer incidence in recipients of kidney retransplantation and primary kidney transplants was compared utilizing Poisson regression, adjusting for demographic and medical characteristics. We assessed 109 224 primary recipients and 6621 retransplants. Compared to primary recipients, retransplants were younger (median age 40 vs. 46 yr), had higher PRA, and more often received induction with polyclonal antibodies (43% vs. 25%). A total of 5757 cancers were observed in primary recipients and 245 in retransplants. Overall cancer risk was similar in retransplants compared with primary recipients (incidence rate ratio [IRR] 1.06, 95% CI 0.93-1.20, adjusted for age, gender, race/ethnicity, PRA, and use of polyclonal induction). However, renal cell carcinoma (RCC) occurred in excess among retransplants (adjusted IRR 2.03, 95% CI 1.45-2.77), based on 514 cases in primary recipients and 43 cases in retransplants. Overall cancer risk did not differ in retransplants compared to primary recipients. Increased risk of RCC may be explained by the presence of acquired cystic kidney disease, which is more likely to develop with additional time with kidney disease and time spent on dialysis waiting for retransplantation.

The hallmarks of cancer: relevance to the pathogenesis of polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a progressive inherited disorder in which renal tissue is gradually replaced with fluid-filled cysts, giving rise to chronic kidney disease (CKD) and progressive loss of renal function. ADPKD is also associated with liver ductal cysts, hypertension, chronic pain and extra-renal problems such as cerebral aneurysms. Intriguingly, improved understanding of the signalling and pathological derangements characteristic of ADPKD has revealed marked similarities to those of solid tumours, even though the gross presentation of tumours and the greater morbidity and mortality associated with tumour invasion and metastasis would initially suggest entirely different disease processes. The commonalities between ADPKD and cancer are provocative, particularly in the context of recent preclinical and clinical studies of ADPKD that have shown promise with drugs that were originally developed for cancer. The potential therapeutic benefit of such repurposing has led us to review in detail the pathological features of ADPKD through the lens of the defined, classic hallmarks of cancer. In addition, we have evaluated features typical of ADPKD, and determined whether evidence supports the presence of such features in cancer cells. This analysis, which places pathological processes in the context of defined signalling pathways and approved signalling inhibitors, highlights potential avenues for further research and therapeutic exploitation in both diseases.

Renal cancer in kidney transplanted patients

Renal cancer occurs more frequently in renal transplanted patients than in the general population, affecting native kidneys in 90% of cases and the graft in 10 %. In addition to general risk factors, malignancy susceptibility may be influenced by immunosuppressive therapy, the use of calcineurin inhibitors (CNI) as compared with mammalian target of rapamycin inhibitors, and the length of dialysis treatment. Acquired cystic kidney disease may increase the risk for renal cancer after transplantation, while autosomal dominant polycystic kidney disease does not seem to predispose to cancer development. Annual ultrasound evaluation seems appropriate in patients with congenital or acquired cystic disease or even a single cyst in native kidneys, and every 2 years in patients older than 60 years if they were on dialysis for more than 5 years before transplantation. Immunosuppression should be lowered in patients who develop renal cancer, by reduction or withdrawal of CNI. Although more evidence is still needed, it seems reasonable to shift patients from CNI to everolimus or sirolimus if not already treated with one of these drugs, with due caution in subjects with chronic allograft nephropathy.

Autosomal-dominant polycystic kidney disease (ADPKD): executive summary from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Autosomal-dominant polycystic kidney disease (ADPKD) affects up to 12 million individuals and is the fourth most common cause for renal replacement therapy worldwide. There have been many recent advances in the understanding of its molecular genetics and biology, and in the diagnosis and management of its manifestations. Yet, diagnosis, evaluation, prevention, and treatment vary widely and there are no broadly accepted practice guidelines. Barriers to translation of basic science breakthroughs to clinical care exist, with considerable heterogeneity across countries. The Kidney Disease: Improving Global Outcomes Controversies Conference on ADPKD brought together a panel of multidisciplinary clinical expertise and engaged patients to identify areas of consensus, gaps in knowledge, and research and health-care priorities related to diagnosis; monitoring of kidney disease progression; management of hypertension, renal function decline and complications; end-stage renal disease; extrarenal complications; and practical integrated patient support. These are summarized in this review.