Multifocal renal cancer: genetic basis and its medical relevance.
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Carcinoma, Papillary↗
Biomedical subjects
W Marston Linehan
Publications and source records attributed to W Marston Linehan.
Molecular alterations in primary prostate cancer after androgen ablation therapy.
PURPOSE: After an initial response to androgen ablation, most prostate tumors recur, ultimately progressing to highly aggressive androgen-independent cancer. The molecular mechanisms underlying progression are not well known in part due to the rarity of androgen-independent samples from primary and metastatic sites. EXPERIMENTAL DESIGN: We compared the gene expression profiles of 10 androgen-independent primary prostate tumor biopsies with 10 primary, untreated androgen-dependent tumors. Samples were laser capture microdissected, the RNA was amplified, and gene expression was assessed using Affymetrix Human Genome U133A GeneChip. Differential expression was examined with principal component analysis, hierarchical clustering, and Student's t testing. Analysis of gene ontology was done with Expression Analysis Systematic Explorer and gene expression data were integrated with genomic alterations with Differential Gene Locus Mapping. RESULTS: Unsupervised principal component analysis showed that the androgen-dependent and androgen-independent tumors segregated from one another. After filtering the data, 239 differentially expressed genes were identified. Two main gene ontologies were found discordant between androgen-independent and androgen-dependent tumors: macromolecule biosynthesis was down-regulated and cell adhesion was up-regulated in androgen-independent tumors. Other differentially expressed genes were related to interleukin-6 signaling as well as angiogenesis, cell adhesion, apoptosis, oxidative stress, and hormone response. The Differential Gene Locus Mapping analysis identified nine regions of potential chromosomal deletion in the androgen-independent tumors, including 1p36, 3p21, 6p21, 8p21, 11p15, 11q12, 12q23, 16q12, and 16q21. CONCLUSIONS: Taken together, these data identify several unique characteristics of androgen-independent prostate cancer that may hold potential for the development of targeted therapeutic intervention.
Aged↗
p53 regulation and function in renal cell carcinoma.
Loss of p53 function is a critical event in tumor evolution. This occurs through a range of molecular events, typically a missense p53 mutation followed by loss of heterozygosity. In many cancers, there is compelling evidence that cells that can compromise p53 function have a selective advantage. The situation in renal cell carcinoma is unclear. It has recently been suggested that p53 function is unusually compromised in renal carcinoma cells by a novel dominant, MDM2/p14ARF-independent mechanism. This is hard to reconcile with other recent studies that have identified p53 as an important prognostic indicator. Indeed, one of these latter studies found that the best predictor of poor outcome was the presence of high levels of both p53 (usually indicative of p53 mutation) and MDM2. Thus, it is important that we gain a clearer understanding of the regulation of p53 and the role of MDM2 in renal cell cancer. To address this, we have investigated the transcriptional activity of p53 in a panel of renal cell carcinoma cell lines and the contribution of MDM2 and p14ARF to p53 regulation. We have found that p53 is functional in p53 wild-type renal cell carcinoma cells and that this activity is significantly regulated by MDM2 and to a much lesser extent by p14ARF. Moreover, following induction of DNA damage with UV, the p53 response in these cells is intact. Thus, future studies of renal cell carcinoma that focus on p53 and MDM2 and their role in determining disease outcome will be required to create a better understanding of this notoriously difficult to manage disease.
Carcinoma, Renal Cell↗
High frequency of somatic frameshift BHD gene mutations in Birt-Hogg-Dubé-associated renal tumors.
The Birt-Hogg-Dubé (BHD) syndrome is an inherited genodermatosis characterized by a predisposition to hamartomatous skin lesions, pulmonary cysts, and renal carcinoma. Seventy-seven renal tumors from 12 patients with germline BHD mutations were examined by DNA sequencing to identify somatic mutations in the second copy of BHD. Sequence alterations were detected in the majority of renal tumors (41 of 77, 53%), with loss of heterozygosity at the BHD locus in a minority of additional tumors (14 of 77, 17%). The somatic mutations were distributed across the entire gene, and the majority resulted in frameshifts that are predicted to truncate the BHD protein. These results support a role for BHD as a tumor suppressor gene that predisposes to the development of renal tumors when both copies are inactivated.
Frameshift Mutation↗
Topotecan blocks hypoxia-inducible factor-1alpha and vascular endothelial growth factor expression induced by insulin-like growth factor-I in neuroblastoma cells.
The extent of angiogenesis and/or vascular endothelial growth factor (VEGF) expression in neuroblastoma tumors correlates with metastases, N-myc amplification, and poor clinical outcome. Understanding the mechanisms regulating VEGF expression in neuroblastoma cells provides additional therapeutic options to control neuroblastoma tumor growth. VEGF mRNA is controlled by growth factors and hypoxia via the transcription factor hypoxia-inducible factor (HIF-1alpha). HIF-1alpha protein levels are regulated by the von Hippel Lindau tumor suppressor gene, VHL, which targets HIF-1alpha degradation. To determine whether the levels of VEGF in neuroblastomas are due to mutations in VHL, we evaluated genomic DNA from 15 neuroblastoma cell lines using PCR. We found no mutations in exons 1, 2, or 3 of the VHL gene. VEGF mRNA levels in neuroblastoma cells cultured in serum-free medium increased after 8 to 16 hours in serum, insulin-like growth factor-I (IGF-I), epidermal growth factor, or platelet-derived growth factor. Serum/IGF-I induced increases in HIF-1alpha protein that temporally paralleled increases in VEGF mRNA, whereas HIF-1beta levels were unaffected. VEGF and HIF-1alpha levels were blocked by inhibitors of phosphatidylinositol 3-kinase and mammalian target of rapamycin. Furthermore, we confirmed that HIF-1alpha mediates approximately 40% of the growth factor activity stimulating VEGF protein expression. Topotecan blocked the IGF-I-stimulated increase in HIF-1alpha but not HIF-1beta, and this resulted in a decrease in VEGF in four neuroblastoma cell lines tested. These data indicate that growth factors in an autocrine or paracrine manner play a major role in regulating VEGF levels in neuroblastoma cells and that targeted therapies to phosphatidylinositol 3-kinase, mammalian target of rapamycin, and/or HIF-1alpha have the potential to inhibit VEGF expression and limit neuroblastoma tumor growth.
Antineoplastic Agents↗
Germline BHD-mutation spectrum and phenotype analysis of a large cohort of families with Birt-Hogg-Dubé syndrome.
Birt-Hogg-Dubé syndrome (BHD), a genodermatosis characterized by multiple hamartomas of the hair follicle (fibrofolliculoma), predisposes individuals to an increased risk of developing renal neoplasms and spontaneous pneumothorax. Previously, we localized the BHD locus (also known as FLCN) to chromosome 17p11.2 by linkage analysis and subsequently identified germline mutations in a novel gene in probands from eight of the nine families with BHD in our screening panel. Affected members of five of the families inherited an insertion/deletion of a cytosine in a C8 tract in exon 11. This mutation was also identified by exon 11 screening in probands from 22 of 52 additional families with BHD and therefore represents a hypermutable "hotspot" for mutation in BHD. Here, we screened the remaining 30 families from this large BHD cohort by direct sequence analysis and identified germline BHD mutations in 84% (51/61) of all families with BHD recruited to our study. Mutations were located along the entire length of the coding region, including 16 insertion/deletion, 3 nonsense, and 3 splice-site mutations. The majority of BHD mutations were predicted to truncate the BHD protein, folliculin. Among patients with a mutation in the exon 11 hotspot, significantly fewer renal tumors were observed in patients with the C-deletion than those with the C-insertion mutation. Coding-sequence mutations were not found, however, in probands from two large families with BHD whose affected members shared their family's BHD-affected haplotype. Of the 53 families with BHD whose members inherited either a germline mutation or the affected haplotype, 24 (45%) had at least one member with renal neoplasms. Three families classified with familial renal oncocytoma were identified with BHD mutations, which represents the first disease gene associated with this rare form of renal neoplasm. This study expands the BHD-mutation spectrum and evaluates genotype-phenotype correlations among families with BHD.
Adenoma, Oxyphilic↗
Differential expression of erythropoietin and its receptor in von hippel-lindau-associated and multiple endocrine neoplasia type 2-associated pheochromocytomas.
Pheochromocytoma is a neuroendocrine tumor associated with a variety of genetic disorders, which include von Hippel-Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN 2), neurofibromatosis type 1, hereditary paraganglioma, and succinate dehydrogenase gene-related tumors. Previous studies of VHL-associated and MEN 2-associated pheochromocytomas suggest morphological, biochemical, and clinical differences exist among the tumors, but the process by which they develop remains unclear. Studies in other VHL-associated tumors suggest that VHL gene deficiency causes coexpression of erythropoietin (Epo) and its receptor (Epo-R), which facilitates tumor growth. The objective of this study was to understand the different process of tumorigenesis for VHL and MEN 2-associated pheochromocytomas. Ten pheochromocytomas (VHL patients n = 5, MEN 2 patients n = 5) were examined for the presence or absence of Epo and Epo-R using Western blot, immunohistochemistry, and RT-PCR analyses. Coexpression of Epo and Epo-R was found in all five VHL-associated pheochromocytomas; in contrast, expression of Epo-R, but not Epo, was documented in all five MEN 2-associated pheochromocytomas. Expression of Epo appears to be a result of VHL gene deficiency, possibly through activation of the hypoxia inducible factor-1 pathway, whereas Epo-R is an embryonal marker whose sustained expression in both VHL- and MEN 2-associated pheochromocytomas reflects an arrest or defect in development. These findings suggest an alternative process of tumorigenesis in VHL- and MEN 2-associated pheochromocytomas and implicate Epo as a clinical biomarker to differentiate these tumors.
Adrenal Gland Neoplasms↗
Hereditary leiomyomatosis associated with bilateral, massive, macronodular adrenocortical disease and atypical cushing syndrome: a clinical and molecular genetic investigation.
Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant disorder caused by mutations in the fumarate hydratase (FH) gene on chromosome 1q42.3-43. Massive macronodular adrenocortical disease (MMAD) is a heterogeneous condition associated with Cushing syndrome (CS) and bilateral hyperplasia of the adrenal glands. In MMAD, cortisol secretion is often mediated by ectopic, adrenocortical expression of receptors for a variety of substances; however, to date, no consistent genetic defects have been identified. In a patient with HLRCC caused by a germline-inactivating FH mutation, we diagnosed atypical (subclinical) CS due to bilateral, ACTH-independent adrenocortical hyperplasia. A clinical protocol for the detection of ectopic expression of various hormone receptors was employed. Histology was consistent with MMAD. The tumor tissue harbored the germline FH mutation and demonstrated allelic losses of the 1q42.3-43 FH locus. We then searched the National Institutes of Health (NIH) databases of patients with MMAD or HLRCC and found at least three other cases with MMAD that had a history of tumors that could be part of HLRCC; among patients with HLRCC, there were several with some adrenal nodularity noted on computed tomography but none with imaging findings consistent with MMAD. From two of the three MMAD patients, adrenocortical tumor DNA was available and sequenced for coding FH mutations; there were none. We conclude that in a patient with HLRCC, adrenal hyperplasia and CS were due to MMAD. The latter was likely due to the FH germline mutation because in tumor cells, only the mutant allele was retained. However, other patients with MMAD and HLRCC, or HLRCC patients with adrenal imaging findings consistent with MMAD, or MMAD patients with somatic FH mutations were not found among the NIH series. Although a fortuitous association cannot be excluded, HLRCC may be added to the short list of monogenic disorders that have been reported to be associated with the development of adrenal tumors; FH may be considered a candidate gene for MMAD.
Adrenal Cortex Neoplasms↗
Coexpression of erythropoietin and erythropoietin receptor in von Hippel-Lindau disease-associated renal cysts and renal cell carcinoma.
Von Hippel-Lindau (VHL) disease is characterized by multiple tumors in specific target organs. The tumors at different sites share distinct morphologic and genetic characteristics but their cell of origin is unknown. We show that VHL disease-associated renal clear cell carcinomas (RCC) consistently coexpress erythropoietin (Epo) and Epo receptor (EpoR). In addition, coexpression of Epo and EpoR is detected in many renal cysts, providing further evidence that renal cysts are potential precursors for RCC. In conjunction with VHL gene deficiency, coexpression of Epo and EpoR in renal cysts and tumors may reflect a developmental arrest in immature mesenchymal cells. Such arrest may lead to autocrine stimulation, cell proliferation, and renal tumor development, similar to tumorigenesis of VHL disease-associated hemangioblastomas.
Blotting, Western↗
HIF overexpression correlates with biallelic loss of fumarate hydratase in renal cancer: novel role of fumarate in regulation of HIF stability.
Individuals with hemizygous germline fumarate hydratase (FH) mutations are predisposed to renal cancer. These tumors predominantly exhibit functional inactivation of the remaining wild-type allele, implicating FH inactivation as a tumor-promoting event. Hypoxia-inducible factors are expressed in many cancers and are increased in clear cell renal carcinomas. Under normoxia, the HIFs are labile due to VHL-dependent proteasomal degradation, but stabilization occurs under hypoxia due to inactivation of HIF prolyl hydroxylase (HPH), which prevents HIF hydroxylation and VHL recognition. We demonstrate that FH inhibition, together with elevated intracellular fumarate, coincides with HIF upregulation. Further, we show that fumarate acts as a competitive inhibitor of HPH. These data delineate a novel fumarate-dependent pathway for regulating HPH activity and HIF protein levels.
Adult↗
Metastatic renal cell carcinoma to contralateral ureter presenting as acute obstructive renal failure after radical nephrectomy.
Metastatic renal cell carcinoma commonly involves the lungs, bone, liver, adrenal glands, and brain. Less commonly affected organs include the gallbladder, thyroid, and pancreas. Even metastatic spread to the contralateral kidney and the bladder has been reported. Computed tomography is the standard imaging technique to evaluate for contralateral involvement. One of the disadvantages of computed tomography as a screening modality is its difficulty in identifying small ureteral lesions. We report a rare case of metastatic renal cell carcinoma in the contralateral ureter presenting as acute obstructive renal failure after radical nephrectomy.
Acute Disease↗
Partial adrenalectomy: the National Cancer Institute experience.
OBJECTIVES: To report our experience of partial adrenalectomy and demonstrate whether adrenal function can be preserved in patients with hereditary adrenal pheochromocytoma. Total adrenalectomy has largely been used in the treatment of patients with hereditary adrenal pheochromocytomas. Adrenal cortical-sparing surgery is an alternative approach that aims to balance tumor removal with preservation of adrenocortical function. METHODS: From 1995 to 2004, 33 patients with hereditary pheochromocytoma presented with adrenal masses. Partial adrenalectomy (open or laparoscopic) was performed if normal adrenocortical tissue was evident on preoperative imaging or intraoperative ultrasonography. Various operative parameters, as well as postoperative function of the residual adrenal remnants, were determined. RESULTS: Of the 33 patients, 8 underwent open partial adrenalectomy and 25 laparoscopic partial adrenalectomy during a 10-year period. Ten patients underwent simultaneous, bilateral partial adrenalectomy and 8 underwent surgery on a solitary adrenal gland, 4 of whom received postoperative steroid replacement (stopped in 3 after 1 to 3 months). All other patients had normal catecholamine levels and remained tumor free by imaging at a mean follow-up of 36 months (range 3 to 102). CONCLUSIONS: Partial adrenalectomy can preserve adrenal function in patients with adrenal masses. The laparoscopic approach is technically safe and associated with less morbidity without compromising tumor removal. With careful surgical planning, especially in patients with tumors in solitary glands, adrenocortical function may be preserved, thereby avoiding the morbidity associated with medical adrenal replacement.
Adolescent↗
Management of von Hippel-Lindau-associated kidney cancer.
Von Hippel-Lindau disease (VHL) is an autosomal-dominant inherited condition that predisposes patients to develop renal cysts and tumors, most commonly in the second to fourth decades of life. Renal cysts and tumors have historically been a major cause of disease-related morbidity and mortality, so urologists are often called on to manage patients with VHL. Knowledge of the extrarenal manifestations of VHL (hemangioblastomas of the central nervous system and retina, endolymphatic sac tumors, pancreatic cysts, epididymal and broad-ligament cysts, and pheochromocytomas) and integration of nonurologic specialties into management teams for VHL patients will help to achieve successful outcomes. Screening for renal manifestations of VHL, by regular imaging of the abdomen, begins late in the second decade of life. Because renal tumors in VHL can be multifocal and bilateral, management can be complex. Radical nephrectomy removes all tissue at risk for forming renal tumors; however, this necessitates renal replacement therapy. In an effort to control cancer effectively while preserving native renal function and minimizing intervention, some researchers have proposed an observational strategy. Patients are screened until the largest tumor reaches 3 cm in diameter, at which time operative intervention is recommended. Nephron-sparing surgery is undertaken, whenever technically feasible, with the goal of removing all tumors in that renal unit. The role of minimally invasive technologies is currently being evaluated in selected patients with VHL renal masses. Elucidation of molecular pathways associated with VHL renal tumors may facilitate development of effective medical treatments for these lesions in the future.
Humans↗
Highlights from the Society of Urologic Oncology 4th annual meeting.
PURPOSE: The 4th annual meeting of the Society of Urologic Oncology (SUO) was held December 5-6, 2003 in Bethesda, Maryland. The meeting was attended by urologists, medical and radiation oncologists, and researchers whose focus is genitourinary (GU) malignancies. More than 500 participants registered for the meeting. MATERIALS AND METHODS: The agenda for the SUO meeting included more than 50 speakers and discussion panels, and addressed a broad range of topics in GU oncology. Transcripts of the proceedings and submitted slide presentations were reviewed for content following the meeting, and the highlights were summarized. These written materials can be accessed through the SUO web site at http://societyofurologiconcology.org. RESULTS: Reviewed session topics included epidemiology of GU malignancies, biomarkers for GU malignancies, cancer genomics, bladder cancer, testis cancer, minimally invasive treatments for GU malignancies, molecular therapeutics and advanced prostate cancer. Significant advances in these fields have directly impacted clinical care and improved patient outcomes across the many disciplines associated with treatment of GU cancers. CONCLUSIONS: The SUO meeting is unique in its multidisciplinary forum and focus on urological oncology. The 2003 meeting highlighted recent advances in epidemiology, clinical management and emerging molecular approaches in the diagnosis and treatment of urological malignancies with several state-of-the-art presentations.
Humans↗
Evaluation and management of renal tumors in the Birt-Hogg-Dubé syndrome.
PURPOSE: Herein we describe the evaluation and management of renal tumors in Birt-Hogg-Dubé (BHD), an autosomal dominant disorder predisposing to cutaneous fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax and renal tumors. MATERIALS AND METHODS: A total of 124 affected individuals underwent comprehensive clinical evaluation, including body computerized tomography, to determine cutaneous, pulmonary and renal manifestations of BHD. Of these individuals 14 had their renal tumors managed at our institution. RESULTS: Of the 124 BHD affected individuals 34 (27%) had renal tumors of various histologies, most commonly hybrid oncocytic tumor and chromophobe renal carcinoma. Average age at renal tumor detection was 50.4 years and multiple tumors were found in a majority of patients. Some patients with renal tumors were identified that did not have the characteristic cutaneous hallmarks of BHD. In 4 of the 14 patients treated at our institution small (less than 3 cm) renal tumors were observed, while 10 others underwent a total of 12 renal procedures, including 4 radical and 8 partial nephrectomies. At a median of 38 months of followup 5 of these 10 patients remained free of disease, 3 had small renal tumors and 2 died of metastatic renal cancer. CONCLUSIONS: Patients with BHD are at risk for multiple renal tumors that are often malignant and can metastasize. Individuals at risk or affected by BHD should be radiographically screened for renal tumors at periodic intervals and they are best treated with nephron sparing surgical approaches. Genetic testing for this syndrome is now available.
Adult↗
Highlights from the Society of Urologic Oncology, 5th Annual Meeting, December 3-4, 2004, Bethesda, Maryland, United States of America.
PURPOSE: The fifth annual meeting of the Society of Urologic Oncology was held December 3 and 4, 2004 in Bethesda, Maryland. The program provides a forum for the discussion of important issues in genitourinary malignancies among urologists, radiation oncologists and medical oncologists. MATERIALS AND METHODS: Agenda topics included kidney cancer, bladder cancer and prostate cancer. Several sessions featured new developments in basic, translational and clinical research. Each session was reviewed for content following the meeting and the highlights were summarized. The Young Urologic Oncologists' Forum was again a successful component of the meeting but it is beyond the scope of this summary. RESULTS: Sessions on kidney cancer focused on molecular genetics and advances in molecular therapeutics. Radio frequency ablation of renal masses was also addressed. Topics discussed in bladder cancer included screening and surgical management. Dr. Donald Skinner received the Huggins Medal and he addressed the society on the management of invasive bladder cancer. Reviewed session topics in prostate cancer included neoadjuvant treatment paradigms, radiation treatment and adjuvant therapy in patients in whom primary treatment has failed. A state-of-the-art lecture addressed hereditary prostate cancer. CONCLUSIONS: The Society of Urologic Oncology meeting is unique in its multidisciplinary forum and focus on urological oncology. The meeting this year highlighted emerging trends, and the current state-of-the-art in kidney, bladder and prostate cancer. Additional focus was given to new molecular based diagnostic and therapeutic strategies for genitourinary malignancies.
Carcinoma, Renal Cell↗
The genetic basis of cancer of kidney cancer: implications for gene-specific clinical management.
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Carcinoma↗
Histomathematical analysis of clinical specimens: challenges and progress.
Proteomic analysis of clinical tissue specimens is a difficult undertaking. Described here is a multiplex study of protein expression levels in histological sections of human prostate that addresses many of the associated challenges. Whole-mount sections from 10 prostatectomy specimens were studied using 15 antibodies, immunohistochemical staining, digital imaging, and mathematical analysis of the data sets. The approach was successful in stratifying cell lineages present in the samples based on proteomic patterns, including differentiating normal epithelium from cancer. This strategy likely will be a useful method for extending the number of proteins that can be analyzed in clinical cancer specimens using currently available laboratory techniques.
Epithelial Cells↗