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Importance: Girentuximab is a chimeric monoclonal antibody that binds carbonic anhydrase IX, a cell surface glycoprotein ubiquitously expressed in clear cell renal cell carcinoma (ccRCC). Its safety and activity in phase 2 studies prompted investigation into its use as adjuvant monotherapy in participants with high-risk ccRCC., Objective: To evaluate the safety and efficacy of adjuvant girentuximab on disease-free survival (DFS) and overall survival (OS) in patients with localized completely resected high-risk ccRCC., Design, Setting, and Participants: The ARISER trial (Adjuvant Rencarex Immunotherapy Phase 3 Trial to Study Efficacy in Nonmetastatic RCC) was a randomized, double-blind, placebo-controlled phase 3 clinical trial that took place between June 10, 2004, and April 2, 2013, at 142 academic medical centers in 15 countries in North and South America and Europe. Eligible adult patients had undergone partial or radical nephrectomy for histologically confirmed ccRCC and fell into 1 of the following high-risk groups: pT3/pT4Nx/N0M0 or pTanyN+M0 or pT1b/pT2Nx/N0M0 with nuclear grade 3 or greater. Patients were assigned via central computerized double-blind 1:1 randomization to receive either a single loading dose of girentuximab, 50 mg (week 1), followed by weekly intravenous infusions of girentuximab, 20 mg (weeks 2-24), or placebo, stratified by risk group and region. The data were analyzed from March 31, 2012, to April 2, 2013., Main Outcomes and Measures: Co-primary end points were DFS and OS, based on imaging studies assessed by independent radiological review committee. Secondary end points included safety, assessed as the rate and grade of adverse events., Results: A total of 864 patients (66% male; median [interquartile range] age, 58 [51-65] years) were randomized to girentuximab (n = 433) or placebo (n = 431). Compared with placebo, participants treated with girentuximab had no statistically significant DFS (hazard ratio, 0.97; 95% CI, 0.79-1.18) or OS advantage (hazard ratio, 0.99; 95% CI, 0.74-1.32). Median DFS was 71.4 months (interquartile range, 3 months to not reached) for girentuximab and never reached for placebo group. Median OS was never reached regardless of treatment. Drug-related adverse events occurred in 185 patients (21.6%), reported comparably between arms. Serious adverse events occurred in 72 patients (8.4%), reported comparably between arms. One drug-related serious adverse event occurred in a patient receiving placebo., Conclusions and Relevance: Girentuximab had no clinical benefit as adjuvant treatment for patients with high-risk ccRCC. The surprisingly long DFS and OS in these patients represent a challenge to adjuvant ccRCC drug development., Trial Registration: clinicaltrials.gov Identifier: NCT00087022.

Introduction and Objective: With a limited number of prognostic and predictive biomarkers available, carbonic anhydrase-IX (CAIX) has served as an important prognostic biomarker for patients with clear cell renal cell carcinoma (ccRCC). However, studies have recently called into question the role of CAIX as a biomarker for ccRCC. To investigate this uncertainty, we quantified the association of CAIX with lymphatic involvement and survival using data from ARISER study (WX-2007-03-HR)--a prospective trial involving subjects with high-risk nonmetastatic ccRCC., Methods and Materials: We reviewed the records of 813 patients enrolled in the ARISER study. Central review of histology, grade, and CAIX staining (frequency and intensity) was performed. CAIX score was derived by multiplying the staining intensity (1-3) by percent positive cells (0%-100%), yielding a range of 0 to 300. We quantified the association of CAIX expression and score with lymphatic spread and survival (disease-free survival [DFS] and overall survival [OS]) using Kaplan-Meier and multivariable propensity score adjusted Cox regression analyses., Results: Median follow-up of the cohort was 54.2 months. Although 56% of subjects with lymphatic involvement had CAIX>85%, only 33% had CAIX score ≥ 200. On multivariable analysis, CAIX>85% was not a statistically significant predictor of DFS and OS (P = 0.06 and P = 0.15, respectively). However, CAIX score ≥ 200, when compared with CAIX score ≤ 100, was associated with improved DFS and OS (P = 0.01 and P = 0.01, respectively) on multivariable analysis., Conclusions: The largest, multicenter, prospective analysis of patients with high-risk nonmetastatic ccRCC demonstrates the utility of CAIX score as a statistically significant prognostic biomarker for survival. We recommend that CAIX score be quantified for all patients with high-risk disease after nephrectomy., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Vimentin is currently used to differentiate between malignant renal carcinomas and benign oncocytomas. Recent reports showing Vimentin positive oncocytomas seriously question the validity of this present diagnostic approach. Vimentin 3 is a spliced variant and ends with a unique C-terminal ending after exon 7 which differentiates it from the full length version that has 9 exons. Therefore, the protein size is different; the full length Vimentin version has a protein size of ~57 kDa and the truncated version of ~47 kDa. We designed an antibody, called Vim3, against the unique C-terminal ending of the Vimentin 3 variant. Using immune histology, immune fluorescence, Western blot, and qRT-PCR analysis, a Vim3 overexpression was detectable exclusively in oncocytoma, making the detection of Vim3 a potential specific marker for benign kidney tumors. This antibody is the first to clearly differentiate benign oncocytoma and the mimicking eosinophilic variants of the RCCs. This differentiation between malignant and benign RCCs is essential for operative planning, follow-up therapy, and patients' survival. In the future the usage of Vimentin antibodies in routine pathology has to be applied with care. Consideration must be given to Vimentin specific binding epitopes otherwise a misdiagnosis of the patients' tumor samples may result.

In this study, immunohistochemical staining pattern of cytochrome c oxidase subunit 1 (CCO1) was investigated in the differentiation of renal oncocytoma (RO) from eosinophilic (EoC) and classic chromophobe renal cell carcinoma (ChRCC). A feature found in ChRCC/EoC but not in RO is the predominance of a perinuclear halo when stained for CCO1. In a cohort of 103 mixed cases including 44 RO, 37 classic ChRCC and 22 EoC, the diagnosis based on this immunohistochemical feature alone was consistent with the previous routine diagnosis in 95.7%. We reached 100% specificity and 81.4% sensitivity of this pattern in ChRCC. Specificity for RO was 93.2% and sensitivity correspondingly 95.5%. We propose a novel and easily interpretable immunohistochemical method for the discrimination of benign RO from certain subtypes of malignant ChRCC. Because of strong similarity in morphology of the 2 entities the diagnosis often cannot be made based on standard histopathology alone. The study describes for the first time the formation of a perinuclear halo in CCO1 immunohistochemistry as a highly specific marker for the diagnosis of ChRCC. We think this method can be a strong amendment for routine diagnostics in renal cell carcinoma.

Until a few years ago, the treatment options for metastatic renal cell cancer (mRCC) were very limited. The growing understanding of the molecular pathomechanisms underlying RCC allowed the development of new treatment approaches. Meanwhile, several approved target-oriented substances from different drug classes are available for mRCC. The mechanism of action of vascular endothelial growth factor (VEGF) and VEGF receptor or mTOR inhibition is well documented by phase III trials and reflected in the current guidelines. However, no predictive biomarkers have been identified in mRCC so far to demonstrate a benefit by a specific compound in an individual patient. Meanwhile, the sequential use of 'targeted therapies' in mRCC has been established as standard treatment. The optimal sequence of available agents is still unclear. A German RCC expert panel discussed and developed an algorithm for the choices of first- and second-line treatment in mRCC based on established clinical criteria.

Renal carcinomas have been classified with increasing accuracy in recent years and new sub-groups have been assigned, which, due to their distinct development pathways, carry varying prognoses and require specific treatment approaches. A range of antibodies are available for their immunohistochemical classification. Identifying a gene defect--mutation, deletion, trisomies and monosomies, oncogene activation--enables the application of targeted therapy, e.g. using antibodies or tyrosine kinase inhibitors in signaling pathways, among others. Renal carcinoma diagnosis by the pathologist is taking on a particularly important role.

Renal cell carcinomas (RCCs) of the clear cell type are associated with alteration of the von Hippel-Lindau (VHL) tumour suppressor gene as well as subsequent stabilization and over-expression of hypoxia inducible factor (HIF), which causes up-regulation of cyclin D1. On the basis of their ability to interact with cyclin D1 we investigated a number of cell cycle proteins to shed further light on the downstream effects of HIF dysregulation. Expression of HIF1alpha, cyclin D1, cyclin-dependent kinase 4 and cyclin-dependent kinase inhibitors p16, p21 and p27 was studied by immunohistochemistry. Since NFkappaB1/RelA have been shown to bind to the cyclin D1 promoter, mRNA expression of these transcription factors was further analysed by quantitative PCR. In RCCs harbouring VHL mutations/hypermethylation, over-expression of HIF1alpha was parallelled by up-regulation of cyclin D1 and CDK4 and down-regulation of p21 and p27. Moreover, p27 expression was inversely correlated with tumour cell differentiation. Comparison of non-tumorous autologous kidney tissues revealed a significant down-regulation of NFkappaB1 mRNA expression in patients harbouring RCC with VHL mutations/hypermethylation. Our data support the notion of a link between VHL deficiency/HIF dysfunction and disturbances of cell cycle control in the tumorigenesis of VHL-negative RCC.

Purpose: Proper HLA class I antigen processing and presentation is a prerequisite for the recognition of tumor cells by cytotoxic T lymphocytes. To date there exist only limited information on the expression of components of the HLA class I associated antigen processing machinery (APM) in surgically removed benign renal cell adenoma, and primary and metastatic renal cell carcinoma (RCC)., Materials and Methods: A total of 133 primary RCCs of different subtypes, 10 renal cell adenoma biopsies, 32 matched metastases of different localization and autologous normal kidney epithelium were immunohistochemically analyzed for the expression of HLA class I antigens, low molecular weight protein (LMP)2 and LMP7, the transporter associated with antigen processing subunit (TAP1) and beta 2-microglobulin (beta 2-m)., Results: Normal kidney tissue showed strong cytoplasmic staining intensity for LMP2, LMP7 and TAP1, whereas beta 2-m and HLA class I heavy chains were detected on the cell surface. A low frequency of HLA class I HC and beta 2-m down-regulation was found in RCC. In contrast, primary RCC and metastases showed a high frequency of a total lack of heterogeneous TAP1, LMP2 and LMP7 expression, which was often coordinately regulated. APM component deficiencies were associated with RCC subtypes but not with tumor grading and staging., Conclusions: HLA class I APM component abnormalities appear to represent an immune escape mechanism of RCC. This finding emphasizes the need to evaluate the integrity and expression of these molecules in patients with RCC, especially in those selected for treatment with T-cell based immunotherapy.

The HLA class I antigen-processing machinery (APM) plays a crucial role in the generation of peptides from endogenously synthesized proteins and in their presentation to cytotoxic T lymphocytes. The potential role of defects of APM components in immune escape mechanisms used by malignant cells has prompted us to analyze their expression in renal cell carcinoma (RCC) lesions with special emphasis on TAP because of its critical role in the loading of HLA class I antigens with peptides. Immunohistochemical staining of 51 formalin-fixed RCC lesions and autologous normal renal epithelium detected transporter associated with antigen processing (TAP)1 and tapasin deficiencies in 63 and 80% of the tumor lesions. Impaired low molecular weight protein (LMP)2 and LMP7 expression was found in 73 and 33% of the RCC lesions analyzed, respectively. In contrast to the high frequency of APM component down-regulation, HLA class I heavy chain and beta(2)-microglobulin defects were detected in only 12 and 10% of the lesions, respectively. Concomitant TAP1 and LMP2 deficiencies were found in approximately 57% of RCC lesions, whereas a coordinated down-regulation of all APM components occurred only in 5% of the tumor specimens analyzed. The presence of APM defects was independent of tumor stage and grade but varied significantly among the RCC subtypes. TAP abnormalities do not appear to be attributable to structural alterations because no mutations in TAP1 were detected in TAP1-deficient RCC lesions. These data suggest that TAP defects in RCC lesions are caused by regulatory abnormalities. Therefore, T-cell-based immunotherapy may benefit from the administration of cytokines that up-regulate TAP expression.

Over the last decade several genetic alterations involved in the pathogenesis and progression of renal cell carcinoma have been identified. These findings will have a wide implication for the diagnosis and management of renal cell carcinomas. This review provides a discussion of general principles of tumor development as well as the specific mechanisms underlying renal carcinogenesis.

Deletions involving 3p are believed to be typical for conventional (clear cell) renal cell carcinoma (cRCC), with confirmed and suspected targets being the VHL and FHIT tumor suppressor genes, respectively. By contrast, 3p deletions are felt to be rare in papillary RCC (pRCC) and chromophobe RCC (chRCC); however, this belief is based on relatively scant data. In particular, 3p14.2 deletions, possibly resulting in FHIT inactivation, have been rarely studied in pRCC or chRCC even though they may be relevant in early renal tumorigenesis. We therefore examined 3p deletion rates and patterns in pRCC and chRCC with particular attention to 3p14.2. We examined 16 chRCCs and 27 pRCCs for loss of heterozygosity (LOH) at 3p25-26 and 3p14.2 using 13 well-mapped microsatellite markers. Those pRCC with LOH at 3p25-26 were also screened for VHL gene mutations. The results were correlated with tumor histology and patient outcome and compared with data we had obtained previously on cRCC. We found similar overall 3p LOH rates in pRCC (59%), chRCC (86.6%), and cRCC (75.8%). In pRCC and chRCC, LOH at 3p25-26 was more common than at 3p14.2, whereas the converse was true for cRCC. In the pRCC with 3p25-26 LOH, we confirmed that this was not associated with mutations of the VHL gene. At 3p14.2, LOH rates of pRCC were lower than those of cRCC and chRCC (p<0.02). All morphotypes showed a predominately interstitial LOH pattern, which was most pronounced in the 3p14.2 region in cRCC. 3p LOH in chRCC was associated with improved patient outcome, mirroring our previous cRCC data. We conclude that 3p LOH is a universal phenomenon in RCC, but has different underlying mechanisms, molecular targets, and implications in the different morphotypes, although FHIT inactivation may play a role in both cRCC and chRCC tumorigenesis.

Alpha-fetoprotein (AFP) is recognized as a tumor marker of yolk sac tumors, liver cancer and some other cancers of the digestive organs. Renal cell carcinoma (RCC) producing AFP is a rare entity. A case of AFP-producing RCC with solitary bone metastasis, but without liver involvement, is reported. The stain specific to AFP proved the presence of AFP in the cytoplasms of more cells of the renal tumors. Additionally, the other published cases are reviewed. These cases indicate that mesoderm-originating malignant tumors such as RCCs can produce AFP in some situations. So, AFP is probably more universal than believed, although it is generally a popular and useful tumor marker for hepatocellular carcinomas and yolk sac tumors., (Copyright 2001 S. Karger AG, Basel.)

The HER-2/neu oncoprotein, a 185 kDa membrane-associated tyrosine kinase with extensive homology to the epidermal growth factor receptor (EGF-R), is overexpressed in breast and ovarian carcinomas. Its overexpression is closely associated with poor prognosis in the course of disease. Here we demonstrate HER-2/neu overexpression in both established cell lines and biopsy material obtained from renal epithelial tumors. Immunohistochemical analysis of human kidney tumor lesions using 2 HER-2/neu-specific antibodies revealed HER-2/neu expression in more than 40% of primary epithelial renal tumors and more than 30% of primary renal cell carcinoma (RCC) specimens. A distinctive HER-2/neu expression pattern was found in different subtypes of kidney tumors with the highest frequency in chromophilic and chromophobic RCC, but neither associated with disease stage nor tumor grade. Eight of 10 RCC cell lines expressed significant levels of HER-2/neu mRNA and protein, but at a lower level compared with HER-2/neu overexpressing ovarian carcinoma cells. To evaluate the immune response against HER-2/neu expressing HLA-A2-positive (HLA-A2(+)) RCC cells, allogeneic HLA-A2-restricted cytotoxic T-lymphocyte (CTL) lines generated by pulsing dendritic cells with 3 different HER-2/neu-derived peptides, (HER-2(9.369), HER-2(9.435) and HER-2(9.689), were utilized in chromium-release assays. Specific lysis of HER-2/neu expressing HLA-A2(+) RCC cell lines was mediated by CTL lines specific for each of these 3 HER-2/neu-derived epitopes. The fine specificity of 2 CTL clones was defined to the epitopes HER-2(9.435) and HER-2(9.689). Their specificity was then confirmed by cold target inhibition assays. In addition, CTL-mediated lysis was enhanced by pulsing tumor cells with exogenous HER-2/neu-specific peptides. Our data suggest that (i) HER-2/neu is heterogeneously expressed in different subtypes of RCC, (ii) HER-2/neu is naturally processed by RCC and (iii) HER-2/neu epitopes presented by RCC can be recognized by HLA-A2-restricted, HER-2/neu-specific CTL., (Copyright 2000 Wiley-Liss, Inc.)

To elucidate the role of somatic alterations for renal cancer etiology and prognosis, we analyzed 227 sporadic renal epithelial tumors for mutations and hypermethylations in the von Hippel-Lindau tumor suppressor gene VHL. Tumors were classified according to the recommendations of the Union Internationale Contre le Cancer (UICC) and the American Joint Committee on Cancer (AJCC). Somatic VHL mutations were identified by PCR, single-strand conformation polymorphism analysis, and sequencing, and hypermethylations were identified by restriction enzyme digestion and Southern blotting. Frequencies of VHL alterations were established, and an association with tumor type or tumor type and tumor stage was evaluated. VHL mutations and hypermethylations were identified in 45% of clear cell renal cell carcinomas (CCRCCs) and occasionally (3 of 28) in papillary (chromophilic) renal cell carcinomas (RCCs). Lack of VHL mutations and hypermethylations in chromophobe RCCs and oncocytomas was statistically significant (P = 0.0001 and P = 0.0004, respectively). RCCs carrying VHL alterations showed, in nine cases (12%), mutations at a hot spot involving a thymine repeat (ATT.TTT) in exon 2. Tumor staging was critical to the VHL mutation/hypermethylation detection rate in CCRCCs shown by separate evaluation of patients from medical centers in Munich, Heidelberg, and Mainz. The spectrum of pT1, pT2, and pT3 CCRCCs and the VHL mutation/hypermethylation detection rate varied among these three groups. Altogether, VHL alterations were significantly associated with pT3 CCRCCs (P = 0.009). This is the first evidence of frequent somatic VHL mutations at a particular site within exon 2 and an association of VHL mutations/hypermethylations with a standard prognostic factor.

The recent new morphological classification of epithelial renal tumors has overcome the former unspecified adenoma and carcinoma classification by introducing a specific subtyping. Today we divide in oncocytic and metanephrogenic renal cell adenomas, clear cell-, papillary-, chromophobe-, and collecting duct associated renal cell carcinomas, and transitional cell- and neuroendocrine renal carcinomas. These entities are characterized by a definite immunohistological marker spectrum and differing histogenetic pathways. New cytogenetic data have proven specific chromosomal aberrations for the different tumor types and have confirmed the morphological classification. Certain genetic changes are correlated to specific pathological phenotypes especially in oncocytic tumors. It is possible now to propose an in part hypothetical kidney tumor model which describes the development and progression of adenomas and carcinomas of the kidney in an adenoma-carcinoma sequence.

Tumors associated with the VHL (von Hippel-Lindau) disease, such as hemangioblastomas and renal carcinomas and their sporadic counterparts, are cystic and well vascularized. Mutations of the VHL tumor-suppressor gene and elevated levels of vascular endothelial growth factor (VEGF) have been described in these tumors. The upregulation of VEGF has been shown in vitro as a consequence of alteration of the VHL gene. No comprehensive in vivo analysis has yet been carried out of the factors affecting tumor growth, vascularization, VEGF, and VHL expression. We performed immunohistochemistry and mRNA studies on primary sporadic renal carcinomas and matching normal renal tissue. We semiquantitatively analyzed 29 renal carcinomas (22 clear cell, 5 chromophilic, 2 chromophobic tumors) for VHL mRNA, and VEGF expression for morphology and tumor size. Immunohistochemistry was carried out for VEGF protein expression, vascularization, and macrophage infiltration. Vascularization of the chromophilic renal carcinomas was lower than that of the clear cell type of renal carcinoma. Low VEGF protein expression was seen in four of the five chromophilic renal carcinomas. We found two groups of clear cell renal cell carcinoma: one with reduced VHL mRNA and increased VEGF mRNA, and the other without significantly altered VHL or VEGF mRNAs. Tumor vascularization was correlated with VEGF protein and seemed to be independent of macrophage infiltration. Our in vivo findings support the inverse relationship between the regulation of VHL and that of VEGF. Our data also indicate that there may be an VHL-independent pathway for the induction of tumor vascularization.

Human kidney proximal tubule epithelia express the ATP-dependent export pump for anionic conjugates encoded by the MRP2 (cMRP/cMOAT) gene (symbol ABCC2). MRP2, the apical isoform of the multidrug resistance protein, is an integral membrane glycoprotein with a molecular mass of approximately 190 kD that was originally cloned from liver and localized to the canalicular (apical) membrane domain of hepatocytes. In this study, MRP2 was detected in human kidney cortex by reverse transcription-PCR followed by sequencing of a 826-bp cDNA fragment and by immunoblotting using two different antibodies. Human MRP2 was localized to the apical brush-border membrane domain of proximal tubules by double and triple immunofluorescence microscopy including laser scanning microscopy. The expression of MRP2 in renal cell carcinoma was studied by reverse transcription-PCR and immunoblotting in samples from patients undergoing tumor-nephrectomy without prior chemotherapy. Clear-cell carcinomas, originating from the proximal tubule epithelium, expressed MRP2 in 95% (18 of 19) of cases. Immunofluorescence microscopy of MRP2 in clear-cell carcinoma showed a lack of a distinct apical-to-basolateral tumor cell polarity and an additional localization of MRP2 on intracellular membranes. MRP2, the first cloned ATP-dependent export pump for anionic conjugates detected in human kidney, may be involved in renal excretion of various anionic endogenous substances, xenobiotics, and cytotoxic drugs. This conjugate-transporting ATPase encoded by the MRP2 gene has a similar substrate specificity as the multidrug resistance protein MRP1, and may contribute to the multidrug resistance of renal clear-cell carcinomas.

Background: The development of renal cell carcinoma (RCC) has been associated with both genetic and environmental factors-with mutations in the von Hippel-Lindau (VHL) tumor suppressor gene for clear-cell RCC specifically and with long-term exposure to high doses of trichloroethylene (TRI), an industrially important solvent, for RCC generally. We investigated whether TRI exposure produces RCC through a specific mutational effect on the VHL gene by analyzing VHL sequences in the RCCs of patients exposed to high, cumulative doses of TRI., Methods: The level of exposure for each of 44 patients with RCC who had known industrial exposure to TRI was classified according to the duration, frequency, and mode of exposure. Samples of normal and cancerous tissues were microdissected from paraffin-embedded tissue. DNA was isolated from these samples, and somatic VHL mutations were identified by polymerase chain reaction analysis, single-strand conformation polymorphism analysis, DNA sequencing, and restriction enzyme digestion. Control samples included RCC DNA from 107 patients without known TRI exposure and lymphocyte DNA from 97 healthy subjects., Results: RCCs of TRI-exposed patients showed somatic VHL mutations in 33 (75%) of 44 cases. The mutations were frequently multiple and accompanied by loss of heterozygosity, and there was an association between the number of mutations and the severity of TRI exposure. We observed a specific mutational hot spot at VHL nucleotide 454 in the RCCs of 13 (39%) of the patients, and this mutation was present in adjacent non-neoplastic kidney parenchyma in four of these patients. The nucleotide 454 mutation was neither detected in any of the RCCs from patients without TRI exposure nor in any of the healthy subjects., Conclusion: Our results suggest that RCC in patients with high, cumulative TRI exposure is associated with a unique mutation pattern in the VHL gene.

Two cases of papillary renal cell carcinoma (RCC) with a karyotype 46,X,t(X;1)(p11.2;q21) in two female patients aged 9 and 29 years are reported. These observations, and the review of the 17 reported cases with a translocation at band Xp11 confirm that this abnormality delineates a clinicopathological entity within the classical papillary RCC, characterized by the early age of occurrence and, probably, distinct histological features. Including these two new female cases, the sex ratio in cases with t(X;1) appears similar to that observed in the other papillary RCC.

The production of metastases depends on changes in a large number of genes. It is also connected with the interaction of tumor cells with the environment. It has been reported that primary tumor clone domination is also an important factor in metastasizing, and in many neoplasms dominating clones are the metastatic forerunners. Up to now it is unknown whether domination of a given clone in a primary renal cell carcinoma is a crucial factor in forming metastases or rather presence or absence of specific genes imposes the major advantage in the metastatic process. To study the presence or absence of the duplication and mitotic nondisjunction event as one of the phenomenon in the creation of metastases, as well as possible derivation of metastatic cells from the minor subclone of primary tumor, we examined three metastatic renal clear-cell carcinomas in which by comparative genomic hybridization we detected the loss of 3p in the primary tumor and two copies of 3p in the corresponding metastasis. Loss of heterozygosity analyses using markers for 3p25 (D3S1038), 3p21.1 (D3S1295), and 3p14.2 (D3S1481) proved heterozygosity of at least two 3p loci in all metastatic tumors, which indicates the absence of mitotic nondisjunction event as a cause of occurrence of two copies of 3p in metastases. Our results suggest that in some of the clear-cell renal carcinomas metastatic cells may derive from minor subclones of primary tumors.

It has recently been shown that tumor-associated antigens (TAAs) can evoke tumor-specific T-cell-defined immune responses in cancer patients, thereby offering the possibility of treating patients with such antigens. To develop T-cell-based immunotherapeutic approaches for renal cell carcinoma (RCC), we studied the mRNA expression profile of the TAAs RAGE-1, tyrosinase, MAGE-1, MAGE-2, NY-ESO-1, Melan-A/MART-1, glycoprotein (gp) 75, gp100, beta-catenin, PRAME, and MUM-1 in 14 human RCC cell lines and in tissue specimens of 37 primary RCCs, 2 related metastases, and 33 specimens of normal renal epithelium. Reverse transcription-PCR was performed with TAA-reactive primers, and the specificity of the PCR products was confirmed by Southern blot and/or direct sequencing. PRAME (10 of 14 cell lines), RAGE-1 (7 of 14 cell lines), and gp75 (4 of 14 cell lines) antigens were expressed in a high percentage of RCC cell lines, although the level of TAA expression varied among the different RCC cell lines. However, low levels of TAA expression in RCC cells are sufficient for recognition by TAA-specific CTLs. Transcription of tyrosinase, Melan-A/MART-1, MAGE-1, MAGE-2, NY-ESO-1, gp100, beta-catenin, and MUM-1 was not detected in any RCC cell line. Approximately 50% of surgically removed neoplasias expressed at least one TAA. RAGE-1 mRNA expression was found in 8 of 39 (21%) RCC samples, PRAME mRNA expression was found in 15 of 39 (40%) RCC samples, and gp75 mRNA expression was found in 4 of 39 (11%) RCC samples, but the expression levels of these TAAs were heterogeneous in the different RCC lesions. One RCC specimen expressed MAGE-2, whereas transcription was not detected in any RCC specimen for MAGE-1, NY-ESO-1, tyrosinase, Melan-A/MART-1, gp100, beta-catenin, and MUM-1. The normal kidney epithelium samples were negative for any TAA tested. Thus, RAGE-1, PRAME, and gp75 expression is found with a different frequency in surgically removed lesions and in RCC cell lines, suggesting that a subgroup of RCC patients could be selected for immunotherapeutic strategies that may benefit from immunization against the RAGE-1, gp75, and/or PRAME antigens. However, additional targets for T-cell-based immunotherapy of RCC have yet to be identified.

Metastatic disease is a well-known complicating factor in the treatment of renal cell cancer. Whereas radical nephrectomy usually is curative in cases of localized disease, no adequate treatment has been established for metastatic renal tumors. Identification of specific chromosome changes or genes responsible for metastatic behavior may lead to new strategies of treatment in the future. In light of this, we cytogenetically analyzed a metastasis of a chromophobe renal cell carcinoma arising in a 73-year-old male and compared the results with genetic data on primary chromophobe renal tumors. The chromosomal pattern of the present case showed, next to the extensive chromosome losses specific for the chromophobe subtype, structural rearrangements involving chromosomes 1, 5, 12, 15, and 18. Determining whether or not (some of) the observed structural changes are important for the metastatic behavior of chromophobe renal cell tumors will have to await further genetic studies on metastases of renal cancer.

Renal-cell cancer comprises a heterogeneous group of tumors, which currently can be sub-divided into morphologically distinct entities, each characterized by a specific combination of genetic changes. Sarcomatoid transformation might occur in any of the sub-types, resulting in tumors consisting of both carcinomatous and sarcomatous components. The specific diagnosis of these neoplasms, as to tumor sub-type, is usually made on the histologic properties of the carcinomatous tissue present. However, this might not reflect the true nature of the sarcomatous component. Since the genetic changes associated with the development of the different sub-types of renal-cell cancer are well established, this knowledge might serve as a tool in diagnosing sarcomatoid tumors. Assessing the genetic constitution of the latter may lead to correct diagnosis. It may also provide valuable information about the genetic changes associated with sarcomatoid transformation. Hence we performed a genetic characterization of a case of sarcomatoid renal-cell cancer, histologically diagnosed as being of the chromophilic type. The observed genetic changes included loss of 3p, 6q, 8p, 9, 13, 14 and 17p, and gain of 5, 12 and 20, as well as a mutation in the coding region of the p53 gene. This combination of genetic changes points to clear-cell rather than chromophilic origin of the sarcomatoid tumor investigated, indicating that the genetic constitution of sarcomatoid tumors may be a more reliable indicator of tumor sub-type than histologic appearance.

Cytogenetic and molecular genetic investigations in cancer are important tools to address problems of oncogenesis and tumor progression, of classification, and of diagnosis of tumors. A combination of advanced molecular genetic, cytogenetic, and (immuno) histopathologic analysis will contribute significantly to the elucidation of the oncogenic steps that lead to immortalization and subsequent malignant behavior. In this review written on the occasion of Dr. Avery Sandberg's 75th anniversary, we will present a model for the pathogenesis of renal cell tumors based on a new cytomorphologic classification and our (cyto)genetic analysis of about 175 renal cell tumors, together with the accumulated data in the literature.

Archival material from primary and metastatic renal clear cell carcinomas of 25 patients was studied by comparative genomic hybridization. Copy number changes of entire chromosomes or chromosomal subregions were detected in 22 primary and 21 metastatic tumors. Copy number changes affected the following chromosomes in at least 20% of the 25 primary tumors (minimal common region given in parentheses): gains were noted for chromosomes 1 (1q21-->q23), 5 (5q31-->q34), 7 (7p), 8 (8q), 16 (16p), 17 (17q12-->qter), 19, and 22 (22q12-->qter); losses were revealed for chromosomes 3 (3p21-->pter), 8 (8p23-->pter), 14(14q21-->qter), and Y. The same chromosomal regions that were involved in primary renal clear cell carcinomas were also found in the respective metastatic tumors but with strikingly different frequencies for a few regions. Metastatic tumors showed a significantly higher frequency of complete or partial gains of the long arm of chromosome 1, in particular at 1q21-->q23 than primary tumors (16 cases versus 6 cases; P < 0.005). These data suggest a correlation of metastatic events in renal clear cell carcinomas with an increase in the copy number of genes located at 1q, in particular at 1q21-->q23. In contrast, the entire or partial loss of the short arm of chromosome 3 was significantly less frequent in metastatic tumors (8 cases versus 15 cases; P < 0.025). The validity of 1q and 3p copy number changes detected by comparative genomic hybridization was confirmed by interphase cytogenetics with region-specific yeast artificial chromosomes to paraffin-embedded tumor tissue sections.

Chromophilic renal cell carcinoma is a distinct type of human renal cancer, only recently recognised and defined by its characteristic histomorphological aspect and cytogenetic aberrations. We are the first to report on the establishment and cytogenetic characterisation of a panel of four permanent cell lines, i.e. chromphi-1, -2, -3 and -4, derived from strictly defined renal cell carcinomas (RCCs) of the chromophilic type and kept in continuous culture for up to 5 years. Immunohistochemistry revealed coexpression of vimentin and cytokeratins in all cell lines the cytokeratin polypeptide patterns, however, varying between the different cell lines. By light and transmission electron microscopy, various amounts of cytoplasmatic glycogen deposition were observed, being most pronounced in chromphi-3 and -4. The mean population doubling time ranged from 24 h (chromphi-1) to 51 h (chromphi-4). Chromphi-1 tumour cells produced slowly growing tumours in nude mice using the subrenal capsule assay. In all cell lines, cytogenetic analysis revealed numerical chromosomal aberrations known to be characteristic for chromophilic RCCs, i.e. loss of the Y chromosome, tri- or tetrasomy of chromosomes 7 and 17 as well as various combinations of additional structural and numerical chromosomal aberrations. Karyological aberrations were least pronounced in chromphi-2 and most complex in chromphi-1. Chromosomal aberrations typically affecting the short arm of chromosome 3 in clear cell RCCs were not observed in any of our cell lines.

The chromosomal pattern of 31 specimens of chromophilic renal-cell cancer (RCC), selected according to the criteria mentioned in the classification of Thoenes and Störkel, is presented. A high male preponderance was found (8.7:1). Cytogenetic analysis revealed a typical pattern of numeric alterations specific for this sub-type in the majority of cases (i.e., --Y,+7, +12, +16, +17, and/or +20), which is different from the chromosomal patterns found in other sub-types of RCC. Gain of chromosome 20, as well as loss of the extra copy of chromosome 17 or loss of 17p, was found to be related to the higher-grade chromophilic carcinomas. None of the 14 cases examined by SSCP analysis revealed mutations of the p53 gene, indicating that other genes at 17(p) might be important in the progression of this sub-type of RCC.

We analyzed 50 sporadic renal cell carcinomas (RCCs) for loss of heterozygosity (LOH) at the chromosomal regions 1p, 2p, 6p, 7q, 10p, 11p, 13q, 14q, 17p, 21q, and 22q. Histologically, the tumors were distinguished into clear cell, chromophilic, and chromophobe carcinomas. Whereas LOH at 14q was identified in 42-64% of all three tumor types, only the chromophobe tumors showed high frequencies of LOH (73-91%) at 1p, 2p, 6p, 10p, 13q, 17p, and 21q. These findings provide substantial evidence that the chromophobe subtype of RCC represents a distinct genetic entity. Thus, specific LOH patterns may define the histogenesis and oncogenesis of chromophobe RCC and may be useful in tumor diagnosis and clinical prognosis.

Purpose: Nephron sparing surgery is being performed increasingly for treatment of renal cell carcinoma, including in select patients with a normal contralateral kidney. The number of tumors in the involved kidney (single versus multiple) and presence or absence of perinephric fat involvement (pathological stage T1 to 2 versus T3A) are important prognostic factors. In a prospective study we evaluated the accuracy of intraoperative histopathological frozen section analysis of renal capsular biopsies for assessing local tumor stage, and the accuracy of intraoperative ultrasonography for assessing tumor focality., Materials and Methods: Intraoperative frozen section biopsies and ultrasonography were compared with information obtained from preoperative computerized tomography (CT), intraoperative inspection of the kidney by the surgeon and permanent histopathological specimens., Results: We evaluated 99 patients (102 kidneys) with localized sold renal masses undergoing either radical nephrectomy (48) or nephron sparing surgery (54). Final pathological analysis revealed 95 renal cell carcinomas (stage T3A in 24), 6 oncocytomas and 1 angiomyolipoma. Multiple tumors were detected in 18 of 102 kidneys overall. Frozen section analysis identified 87% of the stage T3A lesions with no false-positive results, compared to CT, which only identified 67%. Ultrasonography identified 14 of 18 multifocal tumors (78%) and was not more accurate than the combination of CT and intraoperative inspection. However, during nephron sparing surgery ultrasonography was useful to localize the intrarenal extent of tumors (17 cases)., Conclusions: Our results clarify the role of intraoperative ultrasonography and frozen section analysis in patients undergoing nephron sparing surgery for renal cell carcinoma. Frozen section analysis may be useful in select patients with small peripheral tumors who are under consideration for elective nephron sparing surgery.

A variety of cytogenetic aberrations have been reported in sporadic and familial renal cell carcinoma. Rearrangements of the short arm of chromosome 3 (3p), trisomy 17, and nuclear hyperdiploidy have been reported to be common clonal chromosome changes. We analyzed a total of ten tumor-derived cell lines from patients who underwent nephrectomy for renal cell carcinoma employing conventional cytogenetics. All patients received an immunomodulatory therapy based on recombinant interleukin-2 (rIL-2). Tumor stage and grade, histo- and cytopathology, and patients' response to immunotherapy were assessed and correlated statistically to rearrangement of 3p, trisomy 17, and nuclear hyperdiploidy. Trisomy 17 as clonal aberration could be revealed only in papillary renal cell carcinoma, whereas tumors with compact or tubulopapillary growth pattern lacked this abnormality (p < 0.002). One of 3 patients with diploid or near-diploid karyotype (< or = 49 chromosomes) achieved a partial remission while two presented with stable disease after immunotherapy. In contrast, all 6 patients with tumor progression upon rIL-2-based immunotherapy revealed hyperdiploid (> 49 chromosomes) karyotypes. The correlation between hyperdiploidy and tumor progression was found to be statistically significant (p < 0.029). Interestingly, the only patient achieving an objective tumor remission after immunotherapy presented with a normal diploid karyotype. Our findings suggest tumor hyperdiploidy as an adverse prognostic factor in renal cell carcinoma patients receiving rIL-2-based immunotherapy.

Several human renal cell carcinomas with X;autosome translocations have been reported in recent years. The t(X;1)(p11.2;q21) appears to be a specific primary anomaly, suggesting that tumors with this translocation form a distinct subgroup of RCC. Here we report two new cases, one with a t(X;10)(p11.2;q23), the other with a t(X;1)(p11.2;p34). The common breakpoint in Xp11.2 suggests that they belong to the above-mentioned subset of RCC. Using FISH in conjunction with X-specific YAC clones, we demonstrate that the two new cases exhibited distinct breakpoints within Xp11.2.

The chromophobe renal cell carcinoma is a distinct type of renal cancer presumably derived from the intercalated cell of the collecting duct system and exhibiting a better prognosis than other types of renal cell carcinoma. Chromophobe carcinomas can be separated from other types of renal cell carcinoma by their characteristic cytomorphology, ultrastructural appearance, cytoskeletal architecture, and cytogenetic aberrations. As no permanent cell line of the chromophobe tumor type has previously been described, we are the first to report on the successful establishment and characterization of two divergent permanent cell lines, ie, chrompho-A and chrompho-B, derived from the same chromophobe renal cell carcinoma. With immunocytochemistry, two-dimensional gel electrophoresis, and Western blot, chrompho-A and chrompho-B exclusively exhibited cytokeratins (Nos. 7, 8, 18, and 19) but not vimentin. Ultrastructural studies revealed numerous cytoplasmic microvesicles as well as coated vesicles that are known to be characteristic features of the intercalated cell. Chrompho-B cells exhibited a shorter mean population doubling time (tD = 43 hours) than chrompho-A cells (tD = 51 hours). Both cell lines failed to produce tumors in nude mice with the subrenal capsule assay. Cytogenetic analyses revealed hyperdiploid chromosome numbers in both cell lines with telomeric associations as well as numeric aberrations known from chromophobe renal cell carcinomas in vivo.

The current classification of renal-cell adenomas (RCAs) and carcinomas (RCCs) is based on eight basic cell and tumor types (entities) with characteristic morphologic features: (1) RCCs of clear-cell type, (2) RCAs/RCCs of chromophilic-cell type, (3) RCAs/RCCs of chromophobic-cell type, (4) RCCs of duct Bellini type, (5) RCCs of transitional-cell type, (6) RCCs of neuroendocrine type, (7) RCAs of oncocytic type, and (8) RCAs of metanephroid type. Tumors with a proposed histogenesis from the proximal tubule (clear-cell and chromophilic tumors) amount to 85% of renal cancers, whereas tumors with a proposed histogenesis from the connecting tubule/collecting duct (chromophobic-, oncocytic-, and duct Bellini-type tumors) amount to only 11%. The remaining tumor types represent rare entities (less than 1% each). Tumor cytogenetics data confirm the proposed eight morphologic subtypes and give further indications for type-specific tumor development and progression.

Cytotoxic T lymphocyte (CTL) clones directed against autologous renal-cell carcinoma (RCC) cell lines were generated by mixed lymphocyte/tumor-cell culture (MLTC) using peripheral blood lymphocytes (PBL). A CD8+, CD4- CTL clone MZ1257-CTL 5/30 with high cytolytic activity for the autologous tumor cell line MZ1257-RCC was established. No lysis of the autologous EBV-transformed B lymphocytes (EBV-B) or K562 cells was observed. A panel of HLA-A2-matched allogeneic RCC lines was recognized by CTL 5/30. Further specificity analysis showed a cross-reactivity with HLA-A2-matched allogeneic tumor cells of various origins, especially melanoma. CTL 5/30 was also cross-reactive with several HLA-A2-positive allogeneic normal kidney cells in culture. The restriction element identified for CTL 5/30 was HLA-A2, as shown by blocking of cytotoxicity using an anti-HLA-A2 monoclonal antibody (MAb) and by resistance of an HLA-A2-negative melanoma variant SK29-MEL. 1.22 against lysis by CTL 5/30. In this report we demonstrate HLA-A2-restricted recognition of a T-cell-defined antigen on autologous renal-cancer cells. This antigen is also expressed and recognized in association with HLA-A2 on normal kidney cells in culture and other HLA-A2-positive tumor cells. It may therefore be a normal differentiation antigen to which tolerance is incomplete in the renal-cell cancer system investigated.

In this retrospective analysis of 56 patients with multifocal renal cell tumors the effect of secondary tumors on the prognosis was examined and the incidence of tumors in the contralateral kidney was evaluated. All of the primary tumors were renal cell carcinomas, the majority of which had a local tumor stage of pT2 (31 cases, 55.3%) and a cytological grading of 1 (23 cases, 41%). The mean size of the secondary tumors was 1.0 cm. An additional tumor was diagnosed in 23 patients (41%), 2 to 5 secondary tumors in 23 (41%) and more than 5 additional tumors in 10 (18%). The overall 5-year survival rates were 69.4%, 72.2% and 40%, respectively (p = 0.313). Histopathological differentiation of the additional lesions revealed 23.2% renal cell carcinomas, 71.4% adenomas and 5.3% renal tumors of "doubtful dignity," with overall 5-year survival rates of 67.2% for adenomas, and 60.6% for carcinomas and renal tumors of "doubtful dignity" (p = 0.546). After a mean followup of 60 months 33 patients (58.9%) were alive without evidence of disease, 1 (1.7%) was alive with tumor progression, 8 (14.2%) died of the disease and 14 (25%) died of other causes; only 1 patient presented with a tumor in the contralateral kidney (incidence 1.7%). Thus, the overall 5-year survival rate for the entire group was 66.0% and the histopathological parameters of the additional tumors had no effect on the prognosis of the patients.

We analyzed 19 chromophobe renal cell carcinomas by means of comparative genomic hybridization. Two tumors revealed no numerical abnormalities. In the remaining 17 cases we found loss of entire chromosomes with underrepresentation of chromosome 1 occurring in all 17 cases; loss of chromosomes 2, 10, and 13 in 16 cases; loss of chromosomes 6 and 21 in 15 tumors; and loss of chromosome 17 in 13 cases. The loss of the Y chromosome was observed in 6 of 13 tumors from male patients, whereas 1 X chromosome was lost in 3 of 4 tumors obtained from females. Comparative genomic hybridization results were verified by interphase cytogenetics. We conclude that a specific combination of multiple chromosomal losses characterizes chromophobe renal cell carcinomas and may help to differentiate them unequivocally from other types of kidney cancer.

We evaluated 28 patients with advanced renal cell carcinoma for the initial expression of P-glycoprotein (MDR1 gene product) employing immunocytochemistry. Tumor specimens were obtained upon primary tumor nephrectomy. In all patients, progression-free survival time following nephrectomy was evaluated and correlated statistically with the staining results. Progression-free survival of patients with no or very few (< 1%) P-glycoprotein-positive tumor cells (n = 8, median survival 27.0 months) was significantly extended (p < 0.04) as compared to patients with 1% or more P-glycoprotein-positive tumor cells (n = 20, median survival 4.0 months). Correlations with histopathological tumor characteristics were insignificant. These results suggest a potential role for P-glycoprotein as a biologic parameter predictive of tumor progression in renal cell carcinoma patients.

Renal-cell carcinomas (RCC) are clinically, histologically and cytogenetically very heterogeneous. The present histological WHO classification shows no clear correlation between histologic subtypes and specific chromosomal abnormalities. In 1986, a new classification was proposed by Thoenes and Störkel based on the cell type from which the tumor arises. They distinguish 5 cell types: clear-cell, chromophilic, chromophobic, ductus Bellini and oncocytic. Results of 105 primary tumors show that, in this new classification, there is a correlation between different subtypes of renal-cell tumor and specific chromosomal abnormalities at a microscopic and/or molecular level. The clear-cell compact type shows structural aberrations of chromosomes I, 3, 4, 5q, 6, 10q, 11q and 12q, together with polysomy of chromosomes X, 4, 5, 7, 10, 12, 15, 16, 19, 20, 21 and 22, monosomy of chromosomes 3, 8, 9, 13, 14, and loss of Y. The main characteristics of the chromophilic tubulo-papillary type are trisomies 7 and 17, and loss of the Y-chromosome. Chromophobic carcinoma seems to be correlated with, inter alia, polysomy 7, trisomies 12, 16, 18, 19, structural abnormalities of 11q, and telomeric associations. Oncocytomas do not reveal any specific chromosomal anomaly, except for trisomy 7. Loss of heterozygosity on 3p is only found in the clear-cell compact type. Some specific chromosomal abnormalities correlate with a particular grade of the tumor. These correlations support the hypothesis that specific chromosomal abnormalities play a role in the histogenesis and oncogenesis of RCC. They may be important for tumor diagnosis and clinical prognosis.

The clear, chromophilic, and chromophobe types of human renal cell carcinoma have been defined as distinct morphological entities and can be clearly separated by differences of ultrastructural appearance, cytoskeletal architecture, enzyme synthesis, and cytogenetic aberrations. In this report, the cytomorphological aspects of these tumor types are compared in vitro, showing that essential ultrastructural and cytoskeletal characteristics of each tumor type are expressed even after prolonged in vitro cultivation. The pattern of intermediate filament proteins of each tumor type was preserved in vitro, permitting the separation of exclusively cytokeratin-positive chromophobe tumor cells from clear and chromophilic tumor cells with a co-expression of vimentin and cytokeratins. In vitro, the chromophobe tumor cells continued to exhibit abundant cytoplasmatic microvesicles and sparsely distributed "studded" vesicles, which are known to be characteristic features of this tumor type in vivo. This observation confirmed the structural similarity of the chromophobe cell to the 'intercalated cell' of the cortical collecting duct and provided further evidence for the histogenetic derivation of this tumor subtype from the collecting duct system.

A majority of renal-cell tumours retain heterozygosity at the short arm of chromosome 3. To investigate possible histopathological differences between tumours with and without such losses, we compared loss of heterozygosity data from 51 tumours with I histological and 2 different cytological classifications of renal-cell tumour. Using the cytological classification of Thoenes et al., we only found tumours with loss of heterozygosity in these authors' clear-cell category. Possibly, only these tumours arise by a mechanism of double loss of a tumour-suppressor gene on 3p, non-clear-cell renal tumours having a different genetic background. Alternatively, deletions may occur in all subtypes, in which case those subtypes in which no LOH is found may also contain deletions too small to be detected with the set of 3p probes we used. A cytogenetic analysis was carried out on 30 of the tumours. Results of molecular and microscopic cytogenetic analyses did not seem to be in agreement in 12 cases. In 6 of these we found allelic losses in tumours showing morphologically normal copies of chromosome 3. Mitotic recombination or loss of one chromosome 3 homologue followed by duplication of the remaining homologue is a likely explanation. The other 6 cases showed microscopic abnormalities of chromosome 3 which were not reflected, or only partly reflected, as allelic losses. These discrepancies are caused either by the limitations of microscopic analysis in exactly determining a breakpoint or tracing a translocated part of a chromosome, or by the failure of molecular analysis to demonstrate LOH if this occurs in only a minority of cells.

In 133 cases of patients with renal cell carcinoma which infiltrated locally into the renal fatty tissue (stage pT3a, TNM classification of 1987), the prognostic potential of the following parameters was investigated: symptoms, patient's age at the time of operation, tumor size and localization, grade of malignancy, cell type, growth pattern, and prognostic score according to Störkel et al. [Eur Urol 1990;18(suppl 2):36]. Additionally, automated image analysis DNA cytometry was performed on 110/133 carcinomas. After an average observation period of 3.6 years (maximum 10.1 years), 59 (44.4%) of the patients died of their tumors. The cause-specific 5- and 10-year survival rates were 51.3 and 29.1%, respectively. Statistically significant differences (p < 0.05) within the individual parameters were found only for the grade of malignancy and the corresponding prognostic score. Using DNA cytometry, 13 types of renal cell carcinoma were differentiated; 90% of the tumors contained aneuploid cells. Significant differences between these relative to prognosis did not exist. In the case of locally advanced renal cell carcinoma, the DNA histogram does not seem to be superior to conventional prognostic criteria.

Cellular differentiation and mRNA levels of genes involved in kidney growth were investigated in normal kidney cells, cyst-lining epithelial cells of polycystic kidney disease, and renal carcinoma cells (RCC). All cells comparatively studied exhibited an antigenic phenotype of proximal tubular cells as shown by the expression of a panel of brush border membrane enzymes and kidney-associated cell surface antigens. The epithelial developmental antigen Exo-1 was expressed in 50% to 80% of cyst-lining epithelia in polycystic kidney tissue and in 20% to 30% of polycystic kidney cells cultured in vitro. Normal kidney cells and RCC were negative under identical culture conditions. The expression of antigen Exo-1 is associated with hyperproliferation in an epithelial tissue compartment composed of cells which have not yet reached their terminal differentiation state. Increased amounts of mRNA of the growth factor receptor system of epidermal growth factor (EGF) receptor and its ligand transforming growth factor (TGF)-alpha were associated with the malignant phenotype of RCC. Increased expression of EGF receptor and TGF-alpha, although less prominent, were also observed in polycystic kidney cells compared with normal kidney cells. In conclusion, the expression of Exo-1 in cyst-lining epithelial cells of autosomal dominant polycystic kidney disease (ADPKD) and the altered regulation of TGF-alpha and EGF receptor in these cells contribute to the hypothesis that hyperproliferation is an underlying pathogenic mechanism of ADPKD.

1. Only clear cell and chromophilic carcinomas of the kidney exhibit a considerable lymphocytic infiltration which is compatible with some immunological responsiveness. Chromophobic carcinomas and benign oncocytomas seem to be immunologically reactive. This reflects the different antigen spectrum and histogenesis of these tumors (Störkel and Jacobi, 1989). Clear cell and chromophilic carcinomas are derived from the proximal tubule and chromophobic carcinomas and oncocytomas from the collecting duct. 2. The tumor periphery seems to be the place of greatest immunological importance, as basic requirements of a sufficient lymphocyte/tumor cell interaction can only be expected there. If these data are taken into account for a therapeutical approach with biological immune modifiers the size of the tumor (tumor burden) and proliferation index must be considered too. This might be a likely explanation for the positive effect of inhaled interleukin-2 on lung metastasis in renal cell cancers. Harvesting of tumor infiltrating lymphocytes for therapeutical purposes should take these findings into account. 3. In spite of dense lymphocytic infiltration only 3% of the tumor infiltrating lymphocytes exhibit the activation marker CD 25. There seems to be a sufficient T cell locomotion in renal cell carcinomas but an insufficient T-cell activation. Whether this fact is induced by lacking cytokine stimulation of involved lymphocytes or by still unknown mediators of the tumor cells is not yet known and needs further investigation. 4. Clear cell carcinomas exhibit most adhesion molecules and the highest amount of infiltrating cytotoxic T-cells and natural killer cells.(ABSTRACT TRUNCATED AT 250 WORDS)