Expression of hepatocyte growth factor and its receptor C-met in acquired renal cystic disease associated with renal cell carcinoma

Acquired cystic kidney disease in children with kidney failure

BACKGROUND

This study aimed to evaluate the incidence, contributing factors, and clinical outcomes of acquired cystic kidney disease (ACKD) in children undergoing kidney replacement therapy (KRT).

METHODS

We conducted a cross-sectional, territory-wide study at the designated pediatric nephrology center in Hong Kong. ACKD was defined as the presence of ≥ 3 cysts in the native kidneys, excluding congenital or hereditary cystic diseases. Between June to December 2023, all paediatric patients receiving KRT in Hong Kong underwent ultrasonography, non-contrast magnetic resonance imaging (MRI), or both. Contrast-enhanced computed tomography was performed for patients with complex cysts.

RESULTS

Forty-three children (56% female; median age 14.7 years; IQR, 11.7-18.7) were included in the analysis. ACKD was detected in 18 children (42%). Nine subjects had complex cysts (grade 2, n = 5; grade 2F, n = 2; grade 3, n = 2). Most patients with ACKD (89%) were asymptomatic. One patient (5.5%) developed back pain and gross haematuria 72 months after initiation of KRT. Another patient (5.5%) developed infected cyst with back pain and clinical sepsis 60 months following KRT initiation. A dialysis duration of ≥ 28 months was the only significant factor associated with ACKD development (77.8% vs. 40%; p = 0.028; ORadj 6.09, 95% CI 1.43-25.82, p = 0.014). The diagnostic yield of paired ultrasound and MRI was superior to ultrasound alone.

CONCLUSIONS

ACKD is prevalent among children and adolescents with kidney failure, with most cases being asymptomatic, however serious complications may arise. Longer duration of dialysis is significantly associated with ACKD development. Therefore, early transplantation and active ACKD surveillance are crucial for children receiving KRT.

Synchronous bilateral papillary renal cell carcinoma in the native kidneys after 10 Years of renal transplantation: Report of a case and review of the literature

A case of synchronous bilateral native kidneys papillary RCC is presented in a 48 year old patient who underwent a living donor kidney transplant 10 years prior. He was on regular immunosuppressant therapy. Despite the long term follow-up, bilateral cystic and exophytic masses were incidentally found on CT scan. Subsequent bilateral open radical nephrectomy revealed papillary RCC in both kidneys.

Report on post-transplantation cancer in southeast Asia from the Thai kidney transplantation cohort

Post-transplantation cancer is a significant cause of mortality among kidney transplant recipients (KTR). The incidence of post-transplantation cancer varies based on geographic region and ethnicity. However, data on KTR from South East Asia, where characteristics differ from other parts of Asia, is lacking. We conducted a retrospective cohort study at a transplant center in Thailand to investigate the incidence of post-transplantation cancer and mortality rates. Factors associated with post-transplantation cancer and patient outcomes were analyzed using competing-risks regression. The study included 1156 KTR with a post-transplant follow-up duration of 5.1 (2.7-9.4) years. The age- and sex-adjusted incidence rate of post-transplant cancer was highest for urothelial cancer (6.9 per 1000 person-years), which also resulted in the highest standardized incidence ratio (SIR) of 42.5 when compared to the general population. Kidney cancer had the second-highest SIR of 24.4. Increasing age was the factor associated with an increased risk of post-transplant cancer (SHR 1.03; 95% CI 1.01-1.05). Human leukocyte antigen (HLA) DR mismatch was associated with a decreased risk of post-transplant cancer (SHR 0.72; 95% CI 0.52-0.98). Post-transplantation cancer was significantly associated with patient mortality (HR 3.16; 95% CI 2.21-4.52). Cancer significantly contributes to KTR mortality, and the risk profile for cancer development in Thai KTRs differs from that of Western and most Asian counterparts. Further research is essential to explore appropriate screening protocols for countries with high rates of urothelial and kidney cancer, including Thailand.

Development of crizotinib-associated renal cyst in a non-small cell lung cancer patient with ALK fusion: a case report and review of the literature

BACKGROUND

Crizotinib, an oral first-generation tyrosine kinase inhibitor (TKI), is superior to systemic chemotherapy for the treatment of non-small cell lung cancer (NSCLC) with positive rearrangement of anaplastic lymphoma kinase (ALK). However, an increased incidence of renal and hepatic cysts has been reported in the patients on crizotinib treatment.

CASE PRESENTATION

Here, we describe a case of a 71-year-old Chinese women developed multiple cystic lesions in kidney and liver during crizotinib treatment for the primary and metastatic NSCLC. The renal and hepatic cysts were noted by CT scan 3 months after crizotinib treatment, which were spontaneously and significantly regressed after stopping crizotinib.

CONCLUSIONS

Based on literature review and our experience in this case report, we concluded that crizotinib-associated renal cyst (CARCs) has features of malignancy and abscess in radiographic imaging, and thus, pathological confirmation is necessary to avoid inappropriate treatment decision. In addition, to benefit the patients with progress-free survival (PFS), switching from crizotinib to alectinib is recommended for the treatment of NSCLC patients who developed CARCs.

Massive Acquired Renal Cysts Presenting with Bowel Obstruction-Like Symptoms

Acquired cystic kidney disease (ACKD) is rarely massive in size. The great majority is asymptomatic and incidentally found on imaging studies for unrelated causes. We reported a case of an 85-year-old male with bilateral multiple huge acquired renal infected cysts, initially presenting with bowel obstruction-like symptoms. The computed tomography (CT) scan later aided in an accurate diagnosis. Symptomatic huge ACKD has, to our knowledge, scarcely been described. In addition, retroperitoneal lesions resulting in abdominal pain remain unusual and underrecognized in general practice.

Renal Cell Carcinoma in End-Stage Renal Disease: A Review and Update

Renal cell carcinoma (RCC) occurring in the setting of end-stage renal disease (ESRD) shows unique clinicopathological characteristics. The two most frequent types of ESRD-associated RCC are acquired cystic kidney disease-associated renal cell carcinoma (ACKD-RCC) and clear-cell papillary renal cell carcinoma (ccpRCC). Other types of RCC also occur in ESRD, albeit with different frequencies from the non-ESRD general population. The histological features of RCC do not vary in the setting of ESRD vs. non-ESRD, yet other findings, such as multifocality and multiple tumor types, are more frequent in ESRD. Studies have generated novel and important knowledge of the etiology, epidemiology, diagnosis, treatment, immunophenotype, and molecular characteristics of ESRD-associated RCC. Knowledge of these data is important for both pathologists and other physicians who may encounter ESRD patients with RCC. This review presents a comprehensive summary and update of the literature on RCC in ESRD, with a focus on the two most frequent types, ACKD-RCC and ccpRCC.

The Natural Course of Total Kidney Volume in Patients with Autosomal Dominant Polycystic Kidney Disease undergoing Hemodialysis

Objectives: The natural course of native kidneys after hemodialysis initiation in patients with autosomal dominant polycystic kidney disease (ADPKD) remains poorly understood.Methods: We measured the total volumes of native kidneys in 12 patients who had at least one enhanced computed tomography (CT) image both before and after initiation of hemodialysis (group 1) and in 18 patients who had no image before dialysis but more than two images after dialysis (group 2). In patients with images, the last image was used for analysis only after dialysis.Results: The mean total kidney volume (TKV) (± SD) before hemodialysis initiation was 3132 ± 1413 mL and the mean TKV of the last image was 3047 ± 1323 mL in group 1. The mean TKV change rate (%) was - 5.2 ± 27.4% (P > 0.05) during follow-up of 3.9 ± 1.9 years in group 1. The mean TKV change rate was 2.8 ± 34.4% (P > 0.05) in group 2. The follow-up period after dialysis initiation ranged from 4.2 ± 4.7 to 8.0 ± 5.2 years.Conclusions: The results suggest that the TKV of native polycystic kidneys decreases substantially after hemodialysis initiation. This reduction occurs mainly during the early post-hemodialysis period and followed by a slow enlargement of TKV.

Oncogenic mechanisms in renal insufficiency

The prevalence of both cancer and end-stage renal disease is increasing. In addition, medical advances have meant increased survival rates for both diseases. Many chemotherapeutics are renally excreted, and conversely, renal insufficiency promotes a pro-neoplastic state, including genitourinary and other cancers. Dialysis prolongs life while increasing cancer risk. Proposed oncogenic mechanisms include immune dysfunction, chronic inflammation, changes in gut microbiota and stimulation of the renin-angiotensin system. This review summarizes current concepts in the relationship between cancer and renal insufficiency.

Iatrogenic Disease of the Genitourinary Tract

Iatrogenic disease is defined as illness caused by diagnostic procedures or treatment given by health care professionals. More recently described treatment complications involving the genitourinary tract include newly recognized variants of renal carcinoma in the setting of dialysis/end-stage renal disease, treatment effect in genitourinary carcinomas, and medical renal disease caused by drug therapies, including immunotherapy. The objective of this review is to cover iatrogenic inflammatory diseases, pseudotumors and tumors of the kidney, bladder, prostate, testis and paratestis of most interest to surgical pathologists. For this reason, disease caused by the following will not be covered: iatrogenic glomerulonephritis, self-inflicted injury including the introduction of foreign bodies, surgical error, drugs of abuse and herbal medications, and iatrogenic disease in the transplant setting including ischemia/reperfusion injury. Emphasis is placed upon commonly encountered diseases in order to ensure that the review is of utility to practicing pathologists. The clinical context, pathophysiology and histopathology of each disease entity are covered.

Acquired cystic kidney disease: an under-recognized condition in children with end-stage renal disease

Acquired cystic kidney disease (ACKD) is a condition that occurs predominantly in patients with end-stage renal disease (ESRD). In contrast to hereditary cystic kidney disease, ACKD is characterized by the presence of multiple small cysts in bilaterally small kidneys. Limited pediatric data suggest a high incidence (21.6-45.8%) of ACKD in children on dialysis, comparable to that in adults, with an increased frequency associated with a longer duration of dialysis. Recent research has shed light on the pathogenesis of ACKD, such as activation of proto-oncogenes. Although most patients with ACKD are asymptomatic, the condition can be complicated by renal cell carcinoma. Routine surveillance should therefore be considered in at-risk populations.

The renal effects of ALK inhibitors

Anaplastic lymphoma kinase 1 (ALK-1) is a member of the insulin receptor tyrosine kinase family. In clinical practice, three small molecule inhibitors of ALK-1 are used, namely crizotinib, ceritinib and alectinib. Several more agents are in active pre-clinical and clinical studies. Crizotinib is approved for the treatment of advanced ALK-positive non-small cell lung cancer (NSCLC). According to the package insert and published literature, treatment with crizotinib appears to be associated with kidney failure as well as an increased risk for the development and progression of renal cysts. In addition, this agent is associated with development of peripheral edema and rare electrolyte disorders. This review focuses on the adverse renal effects of Crizotinib in clinical practice.

Detection and Clinical Patterns of Nephron Hypertrophy and Nephrosclerosis Among Apparently Healthy Adults

BACKGROUND

Even among ostensibly healthy adults, there is often mild pathology in the kidney. The detection of kidney microstructural variation and pathology by imaging and the clinical pattern associated with these structural findings is unclear.

STUDY DESIGN

Cross-sectional (clinical-pathologic correlation).

SETTING & PARTICIPANTS

Living kidney donors at Mayo Clinic (Minnesota and Arizona sites) and Cleveland Clinic 2000 to 2011.

PREDICTORS

Predonation kidney function, risk factors, and contrast computed tomographic scan of the kidneys. These scans were segmented for cortical volume and medullary volume, reviewed for parenchymal cysts, and scored for kidney surface roughness.

OUTCOMES

Nephrosclerosis (glomerulosclerosis, interstitial fibrosis/tubular atrophy, and arteriosclerosis) and nephron size (glomerular volume, mean profile tubular area, and cortical volume per glomerulus) determined from an implantation biopsy of the kidney cortex at donation.

RESULTS

Among 1,520 living kidney donors, nephrosclerosis associated with increased kidney surface roughness, cysts, and smaller cortical to medullary volume ratio. Larger nephron size (nephron hypertrophy) associated with larger cortical volume. Nephron hypertrophy and larger cortical volume associated with higher systolic blood pressure, glomerular filtration rate, and urine albumin excretion; larger body mass index; higher serum uric acid level; and family history of end-stage renal disease. Both nephron hypertrophy and nephrosclerosis associated with older age and mild hypertension. The net effect of both nephron hypertrophy and nephrosclerosis associating with cortical volume was that nephron hypertrophy diminished volume loss with age-related nephrosclerosis and fully negated volume loss with mild hypertension-related nephrosclerosis.

LIMITATIONS

Kidney donors are selected on health, restricting the spectrum of pathologic findings. Kidney biopsies in living donors are a small tissue sample leading to imprecise estimates of structural findings.

CONCLUSIONS

Among apparently healthy adults, the microstructural findings of nephron hypertrophy and nephrosclerosis differ in their associations with kidney function, macrostructure, and risk factors.

[Renal cysts - A novel complication of crizotinib treatment for lung cancer]

We report the case of a woman with an ALK positive lung adenocarcinoma, who developed bilateral complex renal cysts 17 months after the introduction of treatment with crizotinib. Clinical investigation led to the conclusion that the cysts were due to anticancer drug. Regression of the renal cysts was observed one month after cessation of the crizotinib. This case illustrates that specific and little known toxicities can occur with these novel molecules which have entered use for the management of lung cancer.

Complex renal cysts associated with crizotinib treatment

An apparent causal association between crizotinib treatment and renal cyst development emerged during clinical trials in anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC). Serious adverse event (SAE) reports of renal cysts from a safety database of 1375 patients from four clinical trials were reviewed. A blinded, retrospective, independent radiologic review (IRR) was performed using scans from patients on study for ≥ 6 months in three clinical trials; risk factors for renal cyst development were assessed. Among 17 patients with renal cysts reported as SAEs, evidence of invasion into adjacent structures was noted in seven patients, with no evidence of malignancy found. These patients generally did not require dose reductions, none required permanent crizotinib discontinuation due to this AE, and most continued treatment with clinical benefit. In the blinded IRR, among 255 crizotinib-treated patients, 22%, 3%, and 2% had preexisting simple cysts, complex cysts, or both, respectively. At the 6-month tumor assessment, 9% of all patients had acquired new cysts, and 2% of patients with preexisting cysts had developed new cysts and enlargements (>50%) of preexisting simple cysts. Asians appeared to have an increased risk of developing new cysts on treatment; Koreans in particular had 5.18 times higher odds of developing cysts than non-Asians (95% confidence interval, 1.51-17.78; P = 0.05). Crizotinib treatment appears to be associated with an increased risk of development and progression of renal cysts in patients with ALK-positive NSCLC. While close monitoring is recommended, dosing modification was not generally necessary, allowing patients to remain on crizotinib treatment.

Clinical and pathological outcomes of renal cell carcinoma (RCC) in native kidneys of patients with end-stage renal disease: a long-term comparative retrospective study with RCC diagnosed in the general population

PURPOSE

Patients with end-stage renal disease (ESRD) have an increased risk of developing renal cell carcinoma (RCC). This retrospective study compared clinical and pathological outcomes of RCC occurring in native kidneys of patients with ESRD (whether they underwent kidney transplantation or not) with those of renal tumors diagnosed in the general population.

METHODS

The study included a total of 533 patients with RCC. The ESRD cohort included 92 patients with RCC in native kidneys. Of these, 58 and 34 cases were identified before (pre-Tx group) and after kidney transplantation (post-Tx group), respectively. The control group was composed of 441 RCCs diagnosed in the general population. Variables were compared by chi-square and Student's t tests. Cancer-specific survival was assessed by Kaplan-Meier and Cox methods.

RESULTS

The ESRD groups had smaller (P = 0.001), lower-grade, and lower-stage tumors than the non-ESRD group (P = 0.001). The papillary RCC rate was higher in the ESRD groups (P = 0.01). Ten-year cancer-specific survivals were 94.5, 87.9, and 74.6 % in pre-Tx, post-Tx, and non-ESRD patients, respectively (P = 0.003). Mean follow-up was 90.2 months. At multivariate analysis, tumor size (HR = 1.10), pathological stage (HR = 1.46), presence of nodal (HR = 2.22) and visceral metastases (HR = 3.49), and Fuhrman grade (HR = 1.48) were independent adverse prognostic factors for cancer-specific survival.

CONCLUSIONS

Native kidney RCCs arising in ESRD patients are lower stage and lower grade as compared to RCCs diagnosed in the general population, and these tumors exhibit favorable clinical and outcome features.

Acquired cystic disease-associated renal cell carcinoma: further characterization of the morphologic and immunopathologic features

Acquired cystic disease-associated renal cell carcinoma (ACD-RCC) is a subtype of renal cell carcinoma (RCC) with unique morphologic features found exclusively in the background of end-stage renal disease. We analyzed the clinicopathologic features and immumoreactive profiles of 12 cases of ACD-RCC to further characterize this recently recognized entity. Review of histologic slides was performed in conjunction with immunohistochemical staining directed to the contemporary diagnostic antibodies and the putative target therapy-related markers. Histologically, the tumors showed characteristic inter-or intracellular microlumens and eosinophilic tumor cells. Intratumoral hemosiderin deposition and degenerating foamy tumor cells were consistent findings which were not previously described. Immunohistochemically, all the tumors were positive for alpha-methylacyl-CoA-racemase, CD10, pan-cytokeratin, PTEN (phosphatase and tensin homolog deleted on chromosome 10) and c-met, while negative for carbonic anhydrase-9, CD57, CD68, c-kit, pax-2, platelet-derived growth factor receptor (PDGFR)-α or vascular endothelial growth factor receptor (VEGFR)-2. Heterogenous staining was found for CK7 and kidney-specific cadherin. Positive reaction to c-met suggests its utility as a plausible therapeutic target in ACD-RCC. Thus, we present the unique morphologic and immunopathologic features of ACD-RCC, which may be helpful in both diagnostic and therapeutic aspects.

Renal cell carcinoma (RCC) in patients with end-stage renal disease exhibits many favourable clinical, pathologic, and outcome features compared with RCC in the general population

BACKGROUND

Patients with end-stage renal disease (ESRD) are at risk of developing renal tumours.

OBJECTIVE

Compare clinical, pathologic, and outcome features of renal cell carcinomas (RCCs) in ESRD patients and in patients from the general population.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-four French university departments of urology participated in this retrospective study.

INTERVENTION

All patients were treated according to current European Association of Urology guidelines.

MEASUREMENTS

Age, sex, symptoms, tumour staging and grading, histologic subtype, and outcome were recorded in a unique database. Categoric and continuous variables were compared by using chi-square and student statistical analyses. Cancer-specific survival (CSS) was assessed by Kaplan-Meier and Cox methods.

RESULTS AND LIMITATIONS

The study included 1250 RCC patients: 303 with ESRD and 947 from the general population. In the ESRD patients, age at diagnosis was younger (55 ± 12 yr vs 62 ± 12 yr); mean tumour size was smaller (3.7 ± 2.6 cm vs 7.3 ± 3.8 cm); asymptomatic (87% vs 44%), low-grade (68% vs 42%), and papillary tumours were more frequent (37% vs 7%); and poor performance status (PS; 24% vs 37%) and advanced T categories (≥ 3) were more rare (10% vs 42%). Consistently, nodal invasion (3% vs 12%) and distant metastases (2% vs 15%) occurred less frequently in ESRD patients. After a median follow-up of 33 mo (range: 1-299 mo), 13 ESRD patients (4.3%), and 261 general population patients (27.6%) had died from cancer. In univariate analysis, histologic subtype, symptoms at diagnosis, poor PS, advanced TNM stage, high Fuhrman grade, large tumour size, and non-ESRD diagnosis context were adverse predictors for survival. However, only PS, TNM stage, and Fuhrman grade remained independent CSS predictors in multivariate analysis. The limitation of this study is related to the retrospective design.

CONCLUSIONS

RCC arising in native kidneys of ESRD patients seems to exhibit many favourable clinical, pathologic, and outcome features compared with those diagnosed in patients from the general population.

Failure to ubiquitinate c-Met leads to hyperactivation of mTOR signaling in a mouse model of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited disorder that is caused by mutations at two loci, polycystin 1 (PKD1) and polycystin 2 (PKD2). It is characterized by the formation of multiple cysts in the kidneys that can lead to chronic renal failure. Previous studies have suggested a role for hyperactivation of mammalian target of rapamycin (mTOR) in cystogenesis, but the etiology of mTOR hyperactivation has not been fully elucidated. In this report we have shown that mTOR is hyperactivated in Pkd1-null mouse cells due to failure of the HGF receptor c-Met to be properly ubiquitinated and subsequently degraded after stimulation by HGF. In Pkd1-null cells, Casitas B-lineage lymphoma (c-Cbl), an E3-ubiquitin ligase for c-Met, was sequestered in the Golgi apparatus with α₃β₁ integrin, resulting in the inability to ubiquitinate c-Met. Treatment of mouse Pkd1-null cystic kidneys in organ culture with a c-Met pharmacological inhibitor resulted in inhibition of mTOR activity and blocked cystogenesis in this mouse model of ADPKD. We therefore suggest that blockade of c-Met is a potential novel therapeutic approach to the treatment of ADPKD.

Features and outcomes of renal cell carcinoma of native kidneys in renal transplant recipients

OBJECTIVE

To outline the features and outcomes of renal cell carcinoma (RCC) in native kidneys of renal transplant recipients, who are at increased risk of developing this disease.

PATIENTS AND METHODS

We retrospectively studied the clinicopathological features and survival of 28 surgically treated RCCs, which developed in 24 renal transplant recipients. Features and outcomes were compared with 671 patients with RCC who had no renal transplant.

RESULTS

The median interval between renal transplantation and the occurrence of RCC was 5.6 years. Acquired cystic kidney disease was present in 83% of the transplanted patients. Compared with the patients with RCC and no renal transplant, RCCs of native kidneys in transplant recipients were more frequently incidental findings (92% vs 77%, P = 0.092), multifocal (39% vs 15%, P < 0.001), bilateral (17% vs 4%, P = 0.006), had lower T stages (P = 0.040), were smaller (P = 0.027), of lower grades (P = 0.010), were more frequently papillary (43% vs 19%, P = 0.019) and occurred at a significantly younger age (P = 0.022). After a median follow-up of 6.7 years, eight renal transplant recipients had died (33%), but only two deaths were due to RCC. Survival with metastatic RCC was only 4 months, if a full resection of all metastatic sites was not achieved. In multivariate analysis the presence of a renal transplant had no effect on survival.

CONCLUSIONS

Most RCCs in renal transplant recipients are incidental low-stage, low-grade tumours with a favourable prognosis. The outstanding pathological findings are bilateral occurrence, papillary subtype and multifocality. Prognosis of metastatic RCC is poor but might be favourable if all metastases are resected. Screening for early detection of asymptomatic RCC is advocated.

Met and the epidermal growth factor receptor act cooperatively to regulate final nephron number and maintain collecting duct morphology

Ureteric bud (UB) branching during kidney development determines the final number of nephrons. Although hepatocyte growth factor and its receptor Met have been shown to stimulate branching morphogenesis in explanted embryonic kidneys, loss of Met expression is lethal during early embryogenesis without obvious kidney abnormalities. Met(fl/fl);HoxB7-Cre mice, which lack Met expression selectively in the UB, were generated and found to have a reduction in final nephron number. These mice have increased Egf receptor expression in both the embryonic and adult kidney, and exogenous Egf can partially rescue the branching defect seen in kidney explants. Met(fl/fl);HoxB7-Cre;wa-2/wa-2 mice, which lack normal Egfr and Met signaling, exhibit small kidneys with a marked decrease in UB branching at E14.5 as well as a reduction in final glomerular number. These mice developed progressive interstitial fibrosis surrounding collecting ducts with kidney failure and death by 3-4 weeks of age. Thus, in support of previous in vitro findings, Met and the Egf receptor can act cooperatively to regulate UB branching and mediate maintenance of the normal adult collecting duct.

Scatter Factors in renal disease: Dr. Jeckyll and Mr. Hyde?

The Scatter Factors are two homologous proteins, named Scatter Factor/Hepatocyte Growth Factor and Macrophage Stimulating Protein. Their receptors are the products of two oncogenes, Met and Ron, respectively. The Scatter Factors induce movement, stimulate proliferation, regulate apoptosis and are morphogenic, i.e. operate an integrated program that seems tailored to drive organ development and to regenerate injured tissues. On the other hand, Scatter Factors may be responsible for pathologic tissue remodeling, infiltration of inflammatory cells, and tumor growth and diffusion. The review describes the involvement of Scatter Factors in renal disease, including acute renal failure, glomerulonephritis, chronic fibrosing nephropathies, dialysis, renal transplantation and renal tumors, and discusses the double-faced role of Scatter Factors, that play either a protective or a pathogenic role.

Clear cell papillary renal cell carcinoma: a distinct histopathologic and molecular genetic entity

A group of renal tumors composed mainly of cells with clear cytoplasm arranged in papillary patterns and arising in end-stage kidneys has recently been identified. The aim of our study is to investigate the cytogenetic and immunohistochemical phenotypes of these unusual renal tumors, and of morphologically similar tumors arising in kidneys unaffected by end-stage renal disease. Seven tumors from 5 patients (age range: 53 to 64 y, mean: 60 y; 3 men and 2 women) were identified. Sections were obtained from paraffin blocks, including the tumors and adjacent non-neoplastic renal parenchyma. Interphase fluorescence in situ hybridization was performed with centromeric probes for chromosomes 3, 7, 17, Y, and with a subtelomeric probe for 3p25. Immunohistochemistry was performed with antibodies against cytokeratin 7, carbonic anhydrase IX, alpha-methylacyl-CoA racemase, CD10, and transcription factor E3. Four of the tumors were from patients who did not have end-stage renal disease. One patient had end-stage renal disease and presented with 3 morphologically identical tumors, composed of clear cells arranged in a mixture of cystic and papillary structures. Follow-up data were available from all patients and none showed recurrence or metastasis (mean follow-up: 24 mo). All 7 tumors (ranging from 4 to 50 mm in diameter) were stage pT1. All tumors lacked the gains of chromosome 7 and losses of chromosome Y that are typical of papillary renal cell carcinoma. Only 1 tumor showed gain of chromosome 17. Deletion of 3p, usually seen in clear cell renal cell carcinoma, was not detected. All tumors showed strongly positive immunohistochemical staining for cytokeratin 7 and carbonic anhydrase IX and negative immunostaining with antibodies against alpha-methylacyl-CoA racemase, CD10, and transcription factor E3. In conclusion, clear cell papillary renal cell carcinoma can arise in otherwise normal kidneys and in kidneys with end-stage renal disease. This tumor has immunophenotypic and genetic profiles distinct from those of either classic papillary or clear cell renal cell carcinoma, and should be considered a distinct entity in the spectrum of renal cell neoplasia.

Over expression of hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and nuclear factor kappaB is putatively involved in acquired renal cyst formation and subsequent tumor transformation in patients with end stage renal failure

PURPOSE

We examined hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and nuclear factor-kappaB in acquired cystic disease of the kidney associated with renal cell carcinoma to elucidate the roles of these factors in cyst formation and subsequent tumor transformation.

MATERIALS AND METHODS

Immunohistochemical expression of hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB (active form) were examined in 20 normal kidney samples obtained from nephrectomy for localized renal cell carcinoma and 25 kidneys with acquired cystic disease associated renal cell carcinoma from 23 patients on dialysis.

RESULTS

Only faint or weak immunostaining for hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB was observed in normal kidney tissues. In nontumor areas of the kidneys with acquired cystic disease expressions of these 3 proteins was up-regulated in tubular and cyst epithelial cells. Acquired cysts were classified into 3 types according to cyst epithelium morphology, namely flat, cuboidal and hyperplastic. Hyperplastic cysts were the predominant cysts expressing hypoxia-inducible protein 2 and hypoxia-inducible factor-1alpha. Although up-regulation of hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB was observed in renal cell carcinoma, positive hypoxia-inducible protein 2 immunostaining was detected predominantly in papillary renal cell carcinoma, while positive hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB immunostaining was prominent in clear cell renal cell carcinoma.

CONCLUSIONS

Hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB may be involved in a continuous process of the evolution of phenotypic expression from a simple cyst to epithelial hyperplasia and eventually to tumor.

Prognostic Significance of Vitamin D Receptor and Retinoid X Receptor Expression in Renal Cell Carcinoma

PURPOSE

The active form of vitamin D3, that is 1alpha,25-dihydroxyvitamin D3, binds with vitamin D receptor, which forms a complex with retinoid X receptors alpha, beta and gamma to manifest antitumor effects. We examined the expression of vitamin D receptor and retinoid X receptors in renal cell carcinoma and elucidated the prognostic significance of these receptors.

MATERIALS AND METHODS

We performed immunohistochemical examination of vitamin D receptor, and retinoid X receptors alpha, beta and gamma in nephrectomized specimens of 68 patients with renal cell carcinoma. We analyzed the correlation between the expression of these receptors and clinicopathological parameters or patient survival. Mean followup was 68.2 months.

RESULTS

No significant correlation was found between the expression of vitamin D receptor, retinoid X receptor alpha or beta and clinicopathological parameters. In contrast, retinoid X receptor gamma expression correlated significantly with tumor stage (p = 0.009) and distant metastasis (p = 0.005). The 5-year cancer specific survival rate was higher in patients with retinoid X receptor gamma positive renal cell carcinoma than those with retinoid X receptor gamma negative renal cell carcinoma (79.3% vs 40.0%, p <0.05). Cox regression analysis revealed that retinoid X receptor gamma expression, tumor status and lymph node status were significant independent prognostic factors in patients with renal cell carcinoma (p <0.05). A significant correlation was observed between the expression of retinoid X receptor gamma and tumor stage, distant metastasis or the 5-year cancer specific survival rate. Furthermore, retinoid X receptor gamma expression was an independent prognostic factor in patients with renal cell carcinoma.

CONCLUSIONS

Our observations suggest that alterations of vitamin D receptor and retinoid X receptor expression may be involved in renal carcinogenesis and retinoid X receptor gamma expression may be a useful prognostic marker in patients with renal cell carcinoma.

Acquired cystic disease-associated renal tumors: an immunohistochemical and fluorescence in situ hybridization study

End-stage renal disease is associated with an increased incidence of renal cell neoplasms. Among these, recent studies have identified tumors with unusual histological patterns that do not fit into the categories recognized in the current classification system. These tumors often occur in kidneys with acquired cystic disease and are composed mainly of large eosinophilic cells arranged in solid, cribriform, acinar, or papillary patterns. They also contain deposits of calcium oxalate crystals. We investigated three eosinophilic epithelial tumors arising in kidneys with acquired cystic disease from three patients. Each of the tumors was composed of large eosinophilic cells arranged in solid, acinar, or tubulocystic architecture. Deposits of calcium oxalate crystals were present in each tumor. Hale's colloidal stain showed a positive cytoplasmic reaction in one of the neoplasms. Immunohistochemistry displayed positive results for CD10 (3/3), AE1/AE3 (3/3), alpha-methylacyl-CoA racemase (2/3), CAM5.2 (2/3), and vimentin (1/3). Reactions for epithelial membrane antigen, cytokeratin 7, and high molecular weight cytokeratin (34betaE12) were negative. Fluorescence in situ hybridization analysis showed no losses or gains of chromosomes 1, 2, 6, 10, or 17 in one tumor. There were gains of chromosomes 1, 2, and 6 in two tumors. One of these tumors also showed gains of chromosome 10. Eosinophilic renal cell tumors associated with acquired cystic disease have immunophenotypes and genetic profiles distinct from the renal cell neoplasms recognized in the current classification of renal cell neoplasia, and should be considered as a distinct clinicopathologic entity in the spectrum of renal cell neoplasia.