MOLECULAR GENETIC STUDIES OF SPORADIC AND FAMILIAL RENAL CELL CARCINOMA

Deregulation of energetic metabolism in the clear cell renal cell carcinoma: A multiple pathway analysis based on microarray profiling

Clear cell renal cell carcinoma (ccRCC) is the most frequent type of kidney cancer. In order to better understand the biology of ccRCC, we accomplished the gene profiling of fresh tissue specimens from 11 patients with the renal tumors (9 ccRCCs, 1 oncocytoma and 1 renal B-lymphoma), in which the tumor-related data were compared to the paired healthy kidney tissues from the same patients. All ccRCCs exhibited a considerably elevated transcription of the gene coding for carbonic anhydrase IX (CAIX). Moreover, the ccRCC tumors consistently displayed increased expression of genes encoding the glycolytic pathway enzymes, e.g. hexokinase II (HK2) and lactate dehydrogenase A (LDHA) and a decreased expression of genes for the mitochondrial electron transport chain components, indicating an overall reprogramming of the energetic metabolism in this tumor type. This appears to be accompanied by altered expression of the genes of the pH regulating machinery, including ion and lactate transporters. Immunohistochemical staining of tumor tissue sections confirmed the increased expression of CAIX, HK2 and LDHA in ccRCC, validating the microarray data and supporting their potential as the energetic metabolism-related biomarkers of the ccRCC.

Nephron sparing surgery in von Hippel-Lindau associated renal cell carcinoma; clinicopathological long-term follow-up

We evaluated the clinicopathological outcome of von Hippel-Lindau (VHL)-patients who had mainly undergone nephron sparing surgery (NSS) for renal cell carcinoma (RCC) when the tumour diameter has reached 4.0 cm. Multiple, bilateral RCC with high recurrence rates and subsequent repeated interventions, followed by increasing risk for end-stage renal failure and metastases is characteristic for VHL. NSS is widely used for VHL-associated RCC at 3.0 cm cut-off. 54 VHL patients underwent NSS, nephrectomy or thermal ablation for RCC. We analysed time to second treatment, overall and cancer specific survival, intra- and post-operative data as well as tumour characteristics. We also examined the effects of delaying removal of RCC to 4.0 cm cut-off. Median follow-up was 67 months. 54 patients underwent 97 kidney treatments. 96 % of first and 67 % of second interventions comprised of NSS. 0 % metastases were observed in the group with largest tumour size ≤4 cm. The probability for second surgery was 21 %, at 5 years and 42 % at 10 years. Median time to second NSS was 149.6 months. The overall and cancer specific survival rate was 96.5 and 100 % at 5-year follow-up, and 82.5 and 90.5 % respectively at 10-year follow-up. Median delay to second NSS at 4.0 cm cut-off versus 3.0 cm was 27.8 months. NSS was both successfully used in first and second surgery and to some extent even in third surgery. By following a strict surveillance protocol it is possible to support a 4.0 cm-threshold strategy for NSS, based on the assumption that delaying time to second NSS prevents patients from premature renal failure.

Treatment of patients with metastatic renal cell carcinoma undergoing hemodialysis: case report of two patients and short literature review

Background

Renal cell carcinoma (RCC) may involve both kidneys. When bilateral nephrectomy is necessary renal replacement therapy is mandatory. Treating such patients with sequential therapy based on cytokines, antiangiogenic factors and mammalian target of rapamycin (mTOR) inhibitors is challenging.

Case presentation

The first case, a 50-year-old Caucasian female, underwent a radical right nephrectomy for RCC. Twelve years later she underwent a radical left nephrectomy along with total hysterectomy including bilateral salpingo-oophorectomy for RCC involving the right kidney and ovary. Hemodialysis was necessary because of bilateral nephrectomy. She relapsed with pulmonary metastases and enlarged mediastinal lymph nodes and received cytokine based therapy along with bevacizumab. Therapy was discontinued despite the partial response because of hemorrhagic gastritis. Therapy was switched to an antiangiogenic factor but the patient manifested a parietal brain hematoma and stopped therapy. Subsequently disease relapsed with malignant pleural effusion and pulmonary nodules and a mammalian target of rapamycin inhibitor was administered which was withdrawn only at patient’s deteriorating performance status. The patient died of the disease 13 years after the initial diagnosis of RCC.

The second case, a 51-year-old, Caucasian male, underwent a radical right nephrectomy for a chromophobe RCC. Six months later he underwent a radical left nephrectomy for RCC that proved to be a clear cell RCC. Due to bilateral nephrectomy hemodialysis was obligatory. Following disease recurrence at the anatomical bed of the right kidney therapy with antiangiogenic factor was administered which led to disease regression. However the patient experienced a left temporal-occipital brain hematoma. A radical excision of the recurrence which histologically proved to be a chromophobe RCC was not achieved and the patient received mTOR inhibitor which led to disease complete response. Nine years after the initial diagnosis of RCC he is disease free and leads an active life.

Conclusion

Patients with RCC are in significant risk to manifest bilateral disease. Renal insufficiency requiring hemodialysis poses therapeutic challenges. Clinicians must be aware of the antiangiogenic factors’ adverse effects, especially bleeding, that may manifest in higher frequency and more severe in this setting.

Renal cell carcinoma : clinical features and management

In 1999 it was estimated that renal cell carcinoma (RCC) would account for 29,990 new cancer cases diagnosed in the United States (61% in men and 39% in women), and lead to 11,600 deaths. RCC accounts for 2-3% of all malignancies in adults and causes 2.3% of all cancer deaths in the United States annually (1). Approx 4% of all RCC cases are bilateral at some point in the life of the patient. Data from over 10,000 cases of renal cancer entered in the Connecticut Tumor Registry suggests an increase in the incidence of renal cancer from 1935-1989; in women the incidence increased from 0.7 to 4.2 in 100,000, and in men from 1.6 to 9.6 in 100,000 (2). Factors implicated in the development of RCC include cigarette smoking, exposure to petroleum products, obesity, diuretic use, cadmium exposure, and ionizing radiation (3-9).

Lack of a functional VHL gene product sensitizes renal cell carcinoma cells to the apoptotic effects of the protein synthesis inhibitor verrucarin A

Verrucarin A (VA) is a small molecule derived from the fungal plant pathogen Myrothecium verrucaria and was identified as a selective inhibitor of clear cell renal cell carcinoma (CCRCC) cell proliferation in a high-throughput screen of a library of naturally occurring small molecules. CCRCC arises as a result of loss-of-function mutations in the von Hippel-Lindau (VHL) gene. Here we show that VA inhibits protein translation initiation culminating in apoptosis through the extrinsic signaling pathway. Reintroduction of the VHL gene in CCRCC cells afforded resistance to VA's apoptotic effects. This resistance is mediated in part by the formation of stress granules that entrap signaling molecules that initiate the apoptotic signaling cascade. The VHL gene product was found to be a component of stress granules that develop as result of VA treatment. These findings reveal an important role for the VHL gene product in cytotoxic stress response and have important implications for the rational development of VA-related compounds in chemotherapeutic targeting of CCRCC.

Vascular endothelial growth factor-targeted therapies in advanced renal cell carcinoma

Vascular endothelial growth factor (VEGF) is, to date, the key element in the pathogenesis of renal cell carcinoma (RCC). VEGF pathway activation is responsible for the recruitment, migration, and expansion of endothelial cells, with this angiogenesis tumor model being characteristic of RCC. Different strategies have been developed for almost a decade to block the VEGF pathway in this setting. Four different compounds were approved for metastatic RCC (mRCC) in the past 6 years: bevacizumab, sunitinib, sorafenib, and pazopanib. Axitinib and tivozanib are also promising compounds under evaluation. The revolution in the management and prognosis of patients with mRCC is ongoing.

Long-term management of bilateral, multifocal, recurrent renal carcinoma

Patients with bilateral multifocal renal cell carcinoma are at increased risk of developing locally recurrent or de novo tumors after nephron-sparing procedures. When dealing with recurrent renal masses the options are limited to observation, total nephrectomy, ablation, or repeat surgical intervention. The main reason for recurrence after nephron-sparing surgery is likely to be the presence of multifocal disease, which is identified in 4.3-25.0% of radical nephrectomy specimen. Bilateral renal involvement is seen in almost 90% of cases of multifocal renal carcinoma, and conversely the majority of patients with bilateral disease will have multifocal tumors. Many patients who are treated for multifocal disease, therefore, require subsequent surgical interventions. The outcome data for repeat renal interventions demonstrate reasonable functional and oncologic outcomes despite higher rates of perioperative complications. Our own results support the use of reoperative renal surgery rather than total nephrectomy and renal replacement therapy.

PHD2 in tumour angiogenesis

Originally identified as the enzymes responsible for catalysing the oxidation of specific, conserved proline residues within hypoxia-inducible factor-1α (HIF-1α), the additional roles for the prolyl hydroxylase domain (PHD) proteins have remained elusive. Of the four identified PHD enzymes, PHD2 is considered to be the key oxygen sensor, as knockdown of PHD2 results in elevated HIF protein. Several recent studies have highlighted the importance of PHD2 in tumourigenesis. However, there is conflicting evidence as to the exact role of PHD2 in tumour angiogenesis. The divergence seems to be because of the contribution of stromal-derived PHD2, and in particular the involvement of endothelial cells, vs tumour-derived PHD2. This review summarises our current understanding of PHD2 and tumour angiogenesis, focusing on the influences of PHD2 on vascular normalisation and neovascularisation.

Mutational analysis of hypoxia-related genes HIF1alpha and CUL2 in common human cancers

Hypoxia is a general feature of solid cancer tissues. Hypoxia upregulates hypoxia-inducible factor 1alpha (HIF1alpha) that transactivates downstream genes and contributes to cancer pathogenesis. HIF1alpha is upregulated not only by hypoxia but also by genetic alterations in HIF1alpha-related genes, including VHL. Cullin 2 (CUL2) interacts with the trimeric VHL-elongin B-elongin C complex and plays an essential role in the ubiquitinated degradation of HIF1alpha. The aim of this study was to explore whether HIF1alpha and CUL2 genes are somatically mutated, and contribute to HIF1alpha activation in common human cancers. For this, we have analyzed the coding region of oxygen-dependent degradation domain of HIF1alpha in 47 colon, 47 gastric, 47 breast, 47 lung, and 47 hepatocellular carcinomas, and 47 acute leukemias by a single-strand conformation polymorphism assay. In addition, we analyzed mononucleotide repeat sequences (A8) in CUL2 in 55 colorectal and 45 gastric carcinomas with microsatellite instability (MSI). We found one HIF1alpha mutation (p.Ala593Pro) in the hepatocellular carcinomas (1/47; 2.1%), but none in other cancers. We found two CUL2 frameshift mutations in colon cancers (p.Asn292MetfsX20), which were exclusively detected in high MSI cancers (4.9%; 2/41). Our data indicate that somatic mutation of HIF1alpha is rare in common cancers, and somatic mutation of CUL2 occurs in a fraction of colorectal cancers (colorectal cancers with high MSI). The data suggest that neither HIF1alpha nor CUL2 mutation may play a central role in HIF1alpha activation in gastric, colorectal, breast, lung and hepatocellular carcinomas, and acute leukemias.

The role of hypoxia-inducible factors in tumorigenesis

Hypoxia-inducible factors (HIFs) are essential mediators of the cellular oxygen-signaling pathway. They are heterodimeric transcription factors consisting of an oxygen-sensitive alpha subunit (HIF-alpha) and a constitutive beta subunit (HIF-beta) that facilitate both oxygen delivery and adaptation to oxygen deprivation by regulating the expression of genes that control glucose uptake, metabolism, angiogenesis, erythropoiesis, cell proliferation, and apoptosis. In most experimental models, the HIF pathway is a positive regulator of tumor growth as its inhibition often results in tumor suppression. In clinical samples, HIF is found elevated and correlates with poor patient prognosis in a variety of cancers. In summary, HIF regulates multiple aspects of tumorigenesis, including angiogenesis, proliferation, metabolism, metastasis, differentiation, and response to radiation therapy, making it a critical regulator of the malignant phenotype.

Bilateral synchronous sporadic renal cell carcinoma: surgical management, oncological and functional outcomes

OBJECTIVE

To analyse the functional and oncological outcomes of surgical treatment of bilateral synchronous sporadic renal cell carcinoma (RCC).

PATIENTS AND METHODS

Between 1969 and 2006, 57 patients with bilateral synchronous sporadic RCC were identified from our kidney database. The mean (range) follow-up was 4.8 (0.1-23.8) years; 28 patients (49%) had radical nephrectomy (RN) and contralateral nephron-sparing surgery (NSS), and 22 (39%) had bilateral NSS. The oncological outcome and long-term renal function were analysed.

RESULTS

After excluding four patients (7%) with bilateral benign renal tumours, six (11%) with metastatic bilateral RCC and three (5%) who had bilateral RN, the cancer-specific outcome was analysed. For 44 patients with bilateral RCC who had surgery with intent to cure and avoid dialysis, 13 (30%) had stage pT1a, 10 (23%) pT1b, nine (17%) pT2 and 12 (27%) pT3 disease. At 5 and 10 years, the cancer-specific survival rates were 86% and 75%, and the local recurrence-free survival rates were 87% and 80%. The median serum creatinine level at the latest follow-up was 1.18 mg/dL in patients after bilateral NSS and 1.40 mg/dL after unilateral NSS and contralateral RN (P < 0.05).

CONCLUSIONS

These long-term data support the concept that NSS, whenever possible bilateral, is the treatment of choice for bilateral synchronous sporadic RCC. NSS provides adequate local tumour control and cancer-specific survival. Preservation of renal function is more efficient with bilateral NSS than with unilateral NSS and contralateral RN.

Risk for cancer in patients with Bardet-Biedl syndrome and their relatives

Bardet-Biedl syndrome (BBS) is a rare, autosomal recessive disease with retinal dystrophy leading to blindness, postaxial polydactyly, truncal obesity, learning disabilities, male hypogenitalism, and renal anomalies. Heterozygous carriers of a BBS mutation are not thought to present symptoms of BBS; however, a previous study reported an increased risk of renal cancer among relatives of patients with BBS. This finding was based on the identification of three parents with renal cell carcinoma, representing a 17-fold increased risk. We performed a population-based study in Denmark to examine the incidence of cancer in 116 BBS patients and 428 relatives (96 families) through record linkage of information from files of the Retinitis Pigmentosa Registry, the Central Population Registry, and the Danish Cancer Registry. The clinical diagnosis of BBS was molecularly confirmed in 52% of the patients. Among the patients, two cancers were reported, with 4.3 expected. The cancers were an embryonal carcinoma of the testis in a 23-year-old man and an acoustic neuroma in a 51-year-old man. Among the relatives, 30 cancers were observed, with 45.2 expected. No renal cancers were observed in the two groups. These data do not support the suggested increased risk for renal cancer in relatives of patients with BBS.

Multiple regulatory pathways of vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) expression in tumors

VPF/VEGF is a multi-functional cytokine with important roles in both vasculogenesis and angiogenesis. Its production is generally regulated by local oxygen concentration. Hypoxia stimulates VPF/VEGF production by increasing its gene transcription and the stability of its mRNA. The increase in transcription in hypoxia occurs mainly through the stabilization and activation of the transcription factor, Hypoxia Inducible Factor (HIF). Cellular oxygen concentration is not the only regulator of VPF/VEGF synthesis. Some cancer cells can produce high levels of VPF/VEGF even in normoxia. Clear cell renal carcinoma cell line (RCC) like 786-0, pancreatic carcinoma cell line, ASPC-1, fibrocarcinoma cell line, HT1080, ovarian cancer cells, etc. produce an elevated level of VPF/VEGF, which is not dependent on hypoxia. In this article, we discuss different regulatory pathways in tumor cells comprised of oncogenes, tumor suppressor genes etc. that play important roles, in both the transcription and stability of VPF/VEGF mRNA.

Endolymphatic sac tumors in von Hippel—Lindau disease

Object. Von Hippel—Lindau (VHL) disease is a hereditary multiple-neoplasia syndrome mapping to chromosome 3p25–26. Endolymphatic sac (ELS) tumors have been identified as a neoplastic manifestation of VHL disease. The purpose of this study was to evaluate comprehensively the natural history of inner ear disease in a large population of patients with confirmed or suspected VHL disease and to correlate the clinical features with the VHL genotype.

Methods. The authors collated and analyzed clinical and genotypic data obtained in patients enrolled in an Institutional Review Board—approved protocol in which families and individuals affected by VHL disease were studied. These data included results from multidisciplinary history workups and physical examinations, imaging studies, and a battery of audiological tests.

One hundred seventy-five patients were enrolled in the study, 129 with confirmed VHL disease and 46 of their family members in whom test results for VHL disease were negative and who served as controls. Twenty-one patients had ELS tumors that were evident on magnetic resonance images; three of them had bilateral ELS lesions. Hearing loss, often sudden in onset and severe to profound in nature, vestibulopathy, aural fullness, and tinnitus represented the primary symptoms of ELS tumor. Distinct patterns of auditory and vestibular dysfunction occurred at different stages of the disease. Phenotypic data showed that 17 of 21 patients with ELS tumors did not have pheochromocytomas, whereas all had VHL disease affecting the kidney, all but two had VHL disease affecting the central nervous system, and all but one had disease affecting the pancreas. Genotyping revealed 10 rearrangements (partial deletions), eight single bp substitutions, and one 3-bp insertion. Although there was no difference in the incidence of hearing loss between populations, symptoms of imbalance and aural fullness were more common in patients with VHL disease but without imaging evidence of ELS tumor than they were in family members who did not have VHL disease (p < 0.01).

Conclusions. Endolymphatic sac tumors are frequently associated with VHL disease. Symptoms of disequilibrium or aural fullness in patients with VHL disease may be an early indication of endolymphatic dysfunction. Patients with VHL disease provide a unique opportunity to examine the effects of specific gene mutations and a discrete neoplastic process on the human inner ear. The study of ELS tumors in this group also provides a pathological model of ELS function and supplies evidence for a role of the ELS in clinical Ménière-like disease(s).

Distinct patterns of chromosomal losses in clinically synchronous and asynchronous bilateral renal cell carcinoma

PURPOSE

Bilateral renal cell carcinoma has been reported to occur in 1% to 4% of patients with renal cancer. However, whether bilateral renal cell carcinoma involves metastatic lesions of the contralateral kidney or develops as simultaneous primary tumors remains unclear to date. Thus, we investigated chromosomal losses and von Hippel-Lindau (VHL) gene abnormalities in bilateral tumors from patients with nonfamilial bilateral renal cell carcinoma.

MATERIALS AND METHODS

Genomic DNA was exacted from 2 tumors in 8 patients each with nonfamilial bilateral renal cell carcinoma, including clinically asynchronous and synchronous disease in 5 and 3, respectively. The DNA was then subjected to microsatellite analysis on 13 chromosomal loci. In addition, polymerase chain reaction-single nucleotide specific conformation polymorphism analysis and direct sequencing of 3 exons of the VHL gene were performed.

RESULTS

All 5 asynchronous cases showed loss of the same allele in bilateral tumors, indicating a common clonal origin. In contrast, 2 of the 3 synchronous cases showed different patterns of chromosomal loss in the right and left renal tumors, suggesting bilateral primary origins. The other synchronous case with loss of the same allele in each tumor involved right stage T3b and left stage T1a neoplasms. No VHL gene mutations were detected in any case.

CONCLUSIONS

Except for a small number of cases synchronous and asynchronous bilateral renal cell carcinoma may represent the simultaneous appearance of separate primary tumors and metastatic progression from the contralateral kidney, respectively.

Inhibition of insulin-like growth factor-I-mediated cell signaling by the von Hippel-Lindau gene product in renal cancer

Insulin-like growth factor-I (IGF-I)-mediated signaling is thought to be involved in the regulation of multiple cellular functions in different tumors including renal cell carcinoma (RCC). Blocking IGF-I signaling by any of the several strategies abolishes or delays the progression of a variety of tumors in animal models. Herein, we demonstrate that in RCC cell lines, IGF-I-mediated signaling is found to be inhibited in the presence of wild type von Hippel-Lindau (VHL) tumor suppresser gene. Moreover, molecular modeling and biochemical approaches have revealed that beta-domain of the VHL gene product by interacting directly with protein kinase Cdelta inhibits its association with IGF-IR for downstream signaling. We also demonstrated that RCC has IGF-I-mediated invasive activity where protein kinase Cdelta is an important downstream molecule, and this invasiveness can be blocked by wild type VHL. These experiments thus elucidate a novel tumor suppresser function of VHL with its unique kinase inhibitory domain.

Risk and prognosis in renal neoplasms. A pathologist's prospective

The incidence of renal carcinoma has increased in the United States over the last two decades. An increased rate of detection of incidental tumors and a variety of exogenous risk factors may be responsible for this increase. Pathologic stage and nuclear grade remain the most important and practical prognostic features, however, the specific tumor type has emerged as important as the cytogenetic validation of recent renal carcinoma classification. Proliferation markers, DNA ploidy, and morphometry have powerful predictive value but are handicapped by cost and complexity. The search continues for molecules of diagnostic and prognostic utility that may also impact invasive and metastatic capability for this group of neoplasms whose course is principally determined by the completeness of the original resection.

Papillary renal cell carcinoma with clear cell cytomorphology and chromosomal loss of 3p

AIMS

Cytogenetic studies on renal cell carcinomas (RCCs) have disclosed a correlation between chromosome aberrations and histomorphological features. Nevertheless, it is still controversial whether the cytomorphology of the tumour cells (clear cell, chromophilic, chromophobe) or their growth pattern (nonpapillary, papillary) is more discriminative for the combined histomorphological-cytogenetic classification of RCCs.

METHODS AND RESULTS

Three RCCs with papillary growth pattern and clear cell cytomorphology were analysed by classical cytogenetics using standard G-banding techniques. Each tumour displayed clonal aberrations leading to loss of terminal 3p chromosomal segments. Monosomy 14 was also consistently found. Trisomy 17 was not observed in any of the tumours.

CONCLUSIONS

This series of three RCCs consisting of clear cells with papillary architecture revealed chromosomal aberrations characteristic for the conventional (clear cell) RCC. Irrespective of the predominant papillary growth pattern, none of the cases were characterized by trisomy of chromosomes 3q, 7, 8, 12, 16, 17 and 20 and loss of Y chromosome which are widely regarded as the most consistent genetic alterations for papillary RCC. Therefore, our cytogenetic findings provide evidence that papillary clear cell RCCs should be classified according to their cytomorphology rather than their growth pattern even when papillary architecture is prominent.

Cytogenetic analyses of 85 testicular germ cell tumors: comparison of postchemotherapy and untreated tumors

Cytogenetic analyses of 85 testicular germ cell tumors, of which 54 were karyotypically abnormal, showed recurrent breakpoints at chromosome bands 1p36, 1p13-1qh, 11q23, 19q13, and the pericentromeric regions of the acrocentric chromosomes. Postchemotherapy tumors had significantly more rearrangements of bands 3p25-p26, 6q16-q21, 8p22-p23 when compared with untreated tumors, while untreated tumors had more rearrangements of 9p22-p24 when compared with postchemotherapy tumors. Frequent breakpoints also were identified at 15q15 and 9qh in untreated tumors. Tumors of different histopathology, clinical stage, and treatment status showed no significant differences in the frequencies of i(12p)-positive and i(12p)-negative tumors.

Activation of Sp1-mediated vascular permeability factor/vascular endothelial growth factor transcription requires specific interaction with protein kinase C zeta

The transcription factor Sp1 is ubiquitously expressed and plays a significant role in the constitutive and induced expression of a variety of mammalian genes and may even contribute to tumorigenesis. Here, we describe a novel pathway whereby Sp1 promotes the transcription of vascular permeability factor/vascular endothelial growth factor (VPF/VEGF), a potent angiogenic factor, by interacting directly and specifically with protein kinase C zeta (PKC zeta) isoform in renal cell carcinoma. PKC zeta binds and phosphorylates the zinc finger region of Sp1. Moreover, in the presence of the wild type von Hippel-Lindau gene product, the interaction of Sp1 with PKC zeta is inhibited, and in this manner steady state levels of Sp1 phosphorylation are decreased significantly. Co-transfection of renal cell carcinoma cells and human fibrosarcoma cells with a plasmid overexpressing PKC zeta and VPF/VEGF promoter luciferase constructs results in activation of Sp1-mediated transcription, whereas expression of a dominant-negative mutant of PKC zeta repressed this activation. Taken together, our results suggest a new pathway of cell signaling through PKC zeta and provide an insight into PKC zeta and Sp1-dependent transcriptional regulation of VPF/VEGF expression and thus tumor angiogenesis.

Renal-cell carcinoma in children: a different disorder from its adult counterpart?

BACKGROUND

Renal-cell carcinoma (RCC) is a rare tumor in children. To address whether RCC in children differs from its adult counterpart, we report a series of 16 children with RCC (5 boys, 11 girls, mean age 9.6 years, range 3-19 years) presenting between 1979 and 1996 at three pediatric centers.

PROCEDURE

Pathology showed papillary RCC in five patients (31%). Nonpapillary tumors were present in 11 (69%), of which nine were clear-cell type (56%), one was chromophobe-cell type (6%), and one was granular-cell type (6%). Cytogenetic studies were performed on four.

RESULTS

In two tumors, normal karyotypes (45,XX or 45,XY) were found. In another, there were translocations: t(X;1), t(X;2) and t(6;14). In the fourth, analysis revealed 46,XX/46,X,t(X;17)(p11.2;q25),t(1;12). Several features in this series differ from those reported in adults. In adults, RCC is more frequent in males, is usually nonpapillary, and is characterized cytogenetically by deletions or rearrangements in the short arm of chromosome 3. In contrast, in our series there was no male predominance and a higher proportion of papillary tumors. In addition, two of four cytogenetically analyzed tumors had translocations involving the X chromosome. Translocations involving the Xp11.2 locus have been infrequently reported in both adults and children with papillary RCC.

CONCLUSIONS

The higher frequency of papillary histology and the presence of translocations involving Xp.11.2 in two cases raise the possibility of a unique subtype of RCC in children.

Bilateral non-familial renal cell carcinoma

BACKGROUND

Bilateral renal cell carcinoma (RCC) exists in hereditary forms (von Hippel-Lindau disease, hereditary papillary renal cell carcinoma, and hereditary clear cell renal carcinoma) associated with various chromosomal abnormalities, and non-hereditary, apparently sporadic forms. The focus of this study is the clinical description of the latter entity.

METHODS

Synchronous and asynchronous bilateral RCC were identified from a prospective database of 698 consecutive patients undergoing operation for RCC between July 1989 and December 1997 at Memorial Sloan-Kettering Cancer Center. Non-familial RCC was defined as that occurring in those patients without a family or hereditary history of RCC. Patients' records were evaluated for presentation, surgical approach used, and pathology. Actuarial survival from the date of initial operative treatment until the date of last follow-up or death was determined using the Kaplan-Meier method. Comparisons between groups were made using the Mann-Whitney test.

RESULTS

Thirty-three of 698 (4.7%) patients operated for RCC had bilateral disease. Four of the 33 (12.1%) patients had either VHL or documented hereditary RCC, and 29 of 33 (87.9%) had non-familial RCC. Of the 29 patients, histology was conventional (clear cell) in 17 patients, papillary in 5, oncocytoma in 3, and unclassified in 3. One patient had a conventional (clear cell) histology in the first nephrectomy specimen and chromophobe renal cell carcinoma in the second. Partial nephrectomy was used in 100% of patients. Median follow-up time was 52 months. Actuarial 5-year overall survival was 84.5%, and actuarial disease-specific survival was 93.3% at 5 years for the non-familial RCC patients.

CONCLUSIONS

Non-familial bilateral RCC patients represent a distinct subpopulation of renal cancer patients with a good overall prognosis. Partial nephrectomy is an integral part of the surgical management. Although most bilateral tumors present synchronously, asynchronous lesions may occur many years after original nephrectomy, thus committing the patient to long-term follow-up.

The von Hippel-Lindau gene product inhibits vascular permeability factor/vascular endothelial growth factor expression in renal cell carcinoma by blocking protein kinase C pathways

Mutation or loss of function of the von Hippel-Lindau (VHL) tumor suppressor gene is regularly found in sporadic renal cell carcinomas (RCC), well vascularized malignant tumors that characteristically overexpress vascular permeability factor/vascular endothelial growth factor (VPF/VEGF). The wild-type VHL (wt-VHL) gene product acts to suppress VPF/VEGF expression, which is overexpressed when wt-VHL is inactive. The present study investigated the pathways by which VHL regulates VPF/VEGF expression. We found that inhibition of protein kinase C (PKC) represses VPF/VEGF expression in RCC cells that regularly overexpress VPF/VEGF. The wt-VHL expressed by stably transfected RCC cells forms cytoplasmic complexes with two specific PKC isoforms, zeta and delta, and prevents their translocation to the cell membrane where they otherwise would engage in signaling steps that lead to VPF/VEGF overexpression. Other experiments implicated mitogen-activated protein kinase (MAPK) phosphorylation as a downstream step in PKC regulation of VPF/VEGF expression. Taken together, these data demonstrate that wt-VHL, by neutralizing PKC isoforms zeta and delta and thereby inhibiting MAPK activation, plays an important role in preventing aberrant VPF/VEGF overexpression and the angiogenesis that results from such overexpression.

Embolization as treatment for spinal cord compression from renal cell carcinoma: case report

OBJECTIVE AND IMPORTANCE

Metastatic renal cell carcinoma may involve the vertebrae, resulting in acute spinal cord compression. Embolization has been used to reduce operative blood loss during surgical decompression, but it has not been considered as an alternative that may eliminate the need for open debulking.

CLINICAL PRESENTATION

A case is presented of a 30-year-old woman with renal cell carcinoma who developed increasing severe back pain, lower extremity weakness, and sensory loss. Magnetic resonance evaluation revealed a T5 metastasis, resulting in significant spinal cord compression.

INTERVENTION

Transarterial embolization was performed with polyvinyl alcohol particles and platinum microcoils. One month after embolization, the patient's lower extremity strength and sensation had improved, and magnetic resonance imaging demonstrated a dramatic response with a significant reduction of cord compression. She deteriorated again 4 months later, and a new sacral mass was embolized. She again improved after treatment.

CONCLUSION

This report illustrates that embolization may be used as palliative treatment for spinal cord compression and obviate the need for open surgical decompression.

Papillary renal cell carcinoma: quantitation of chromosomes 7 and 17 by FISH, analysis of chromosome 3p for LOH, and DNA ploidy

Papillary renal cell carcinoma (papillary RCC) is an uncommon histologic variant of RCC with distinct gross, microscopic, and immunohistochemical features. Recent karyotypic analyses suggest that papillary RCC differs from other types of RCC at the genetic level as well. Whereas nonpapillary (clear cell, granular cell) RCC is characterized by deletions in chromosome 3p, papillary tumors reportedly exhibit a pattern of chromosomal trisomies, typically including chromosomes 7 and 17. To further examine the relationship between overrepresentation of these chromosomes and papillary histology, archival material from 36 papillary tumors was subjected to fluorescence in situ hybridization (FISH) analysis using alpha-satellite repeat probes specific to 7 and 17. Excess signals for chromosome 17 were detected in 22 of 28 (78%) low-grade papillary tumors (Fuhrman nuclear grades 1 and 2), and in seven of eight (87%) high-grade tumors (grades 3 and 4). Correlation of chromosome 17 FISH signals with karyotypes performed on two low-grade and three high-grade tumors was excellent. Among the cases without evidence of excess chromosome 17 were three unusual papillary tumors with sclerotic and hyalinized fibrovascular cores. In two cases, comparison was made of FISH signals from multiple, separate gross nodules of tumor; concordance for trisomic 17 signals was observed in one case, but not in the other. Chromosome 7 signals were overrepresented in all seven papillary tumors examined. DNA ploidy was determined in 19 of the 36 tumors; a relationship between DNA ploidy and polysomy 7 or 17 was not apparent. To examine the possible role of chromosome 3p deletions in the development of papillary RCC, 11 cases were studied for loss of heterozygosity (LOH) at one or more loci in the region of 3p13-21. Only three of the 11 cases had LOH at these loci. The findings are discussed with respect to the development and progression of papillary RCC.