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W Marston Linehan

Publications and source records attributed to W Marston Linehan.

At least 91 records · Page 5Linked to original sources
PubMed2003

Molecular differentiation of high- and moderate-grade human prostate cancer by cDNA microarray analysis.

The prognosis of men with moderate-grade prostate cancer is uncertain. At present, there are few if any reliable molecular markers that can distinguish moderate-grade tumors from those that behave more aggressively. To better understand the molecular basis of human prostate cancer and potentially provide information toward more accurate prognosis, we measured and analyzed gene expression profiles of 13 high- and moderate-grade human prostate tumors using cDNA microarrays. The expression of 136 genes was observed to differ significantly (P < 0.001) between normal prostate and tumors using one-sample t testing and Wilcoxon ranking. Hierarchical clustering of genes demonstrated a relatively similar pattern of differential expression across the tumors. However, importantly, permutation t tests (two-tailed P < 0.001) revealed 21 genes whose expression profiles segregated moderate- and high-grade tumors from each other, which was significantly (P < 0.03) greater than what was expected by chance. These results were compared in silico with prostate cancer profiling efforts performed by other groups, including a meta-analysis of four data sets, which validated many of the dysregulated genes. We suggest that these data provide insight into the molecular nature of clinically aggressive prostate cancer.

Adenocarcinoma↗
PubMed2003

Surgical management of multi-organ visceral tumors in patients with von Hippel-Lindau disease: a single stage approach.

PURPOSE: We assessed surgical feasibility of a 1-stage multi-organ approach for multiple visceral tumors in patients with von Hippel-Lindau disease. MATERIALS AND METHODS: A total of 14 men and 15 women with von Hippel-Lindau disease underwent simultaneous multi-organ surgery for multiple adrenal, renal and pancreatic tumors at the National Cancer Institute between 1988 and 2001. Perioperative and followup data were analyzed retrospectively. The Mann-Whitney U test was used for statistical analysis. RESULTS: Surgery involving 2 or more organs (mean 2.4 procedures per patient, range 2 to 4) was performed in all patients and concurrent pancreatic operations were performed in 12 (41%). Overall a combined 71 procedures, were performed including 4 cases (13%) treated laparoscopically. Mean +/- SD operative time and estimated blood loss were 464 +/- 142 minutes (range 206 to 830) and 2,798 +/- 4,285 cc (300 to 20,000), respectively. In 16 patients (55%) blood transfusion was administered intraoperatively. At a median followup of 21 months (range 5 to 151) renal tumors recurred in 8 patients (28%), requiring further kidney operations, but no patient had pancreatic or adrenal recurrence. The overall complication rate was 38%, and there was no operative mortality. CONCLUSIONS: A single stage surgical approach for multi-organ visceral tumors is a viable option for patients with von Hippel-Lindau disease. With careful patient selection and surgical planning combined procedures can be safely performed in 1 operative setting.

Adolescent↗
PubMed2003

The genetic basis of cancer of the kidney.

PURPOSE: The types of epithelial renal tumors are clear cell, types I and II papillary, chromophobe and oncocytoma. We identified the genetic basis of these different types of kidney cancer to provide better methods for early diagnosis of this disease as well as provide the foundation for the development of molecular therapeutic approaches. MATERIALS AND METHODS: To identify the genetic basis of kidney cancer we studied families with an inherited predisposition to kidney cancer. Families in which 2 or more individuals had kidney cancer underwent a comprehensive evaluation to determine whether they were affected with a hereditary form of renal carcinoma. Genetic linkage analysis was performed to identify the gene for inherited forms of renal carcinoma. RESULTS: The gene for the inherited form of clear cell renal carcinoma associated with von Hippel-Lindau gene was identified. This gene has been found to be a tumor suppressor gene. A new form of inherited renal carcinoma, hereditary papillary renal carcinoma, was identified. The gene for this condition was identified and found to be the proto-oncogene c-Met. A previously unidentified form of familial renal oncocytoma was found. A familial form of chromophobe renal carcinoma and oncocytoma associated with Birt Hogg Dubé syndrome was found. The gene for this condition was localized on the short arm of chromosome 17 and it has been identified. We studied families with cutaneous leiomyomas, uterine leiomyomas and papillary renal carcinoma. We identified mutations in the fumarate hydratase gene in patients affected with this disorder, namely hereditary leiomyoma renal cell carcinoma. CONCLUSIONS: Kidney cancer used to be considered a single disease. It is now known that there are a number of different types of cancers of the kidney with different histological patterns and different clinical courses that appear to respond differently to therapy. These different types of kidney cancer are caused by different genes, ie they each have a distinct genetic basis. Understanding the molecular pathways of these cancer genes should provide insight into their varying clinical courses and responses to treatment as well as provide the foundation for the development of disease specific molecular therapeutic strategies.

Carcinoma, Papillary↗
PubMed2003

Hereditary renal cancers.

Hereditary renal cancer syndromes can lead to multiple bilateral kidney tumors that occur at a younger age than do nonhereditary renal cancers. Imaging plays an important role in the diagnosis and management of these syndromes. During the past decade, several new hereditary renal syndromes have been discovered but are not yet widely known. Whereas previously, the list of hereditary renal cancers in adults included von Hippel-Lindau disease and a rare form of chromosomal translocation, the list now includes the following syndromes: tuberous sclerosis, hereditary papillary renal cancer, Birt-Hogg-Dubé syndrome, hereditary leiomyoma renal cell carcinoma, familial renal oncocytoma, hereditary nonpolyposis colon cancer, and medullary carcinoma of the kidney. In addition, a number of newly described but poorly understood syndromes are under investigation. Even at this early stage, it is clear that elucidation of the underlying genetic mutations that cause hereditary renal cancer syndromes will have profound implications for understanding the origins of nonhereditary renal tumors. These studies will likely culminate in a better understanding of the causes of renal cancer, its prevention, and, ultimately, its cure.

Carcinoma, Medullary↗
PubMed2003

MDA-7 (interleukin-24) inhibits the proliferation of renal carcinoma cells and interacts with free radicals to promote cell death and loss of reproductive capacity.

The median survival of metastatic renal cell carcinoma (RCC) is 12 months, and the majority of treatment options are palliative. MDA-7 (interleukin-24), when expressed via a recombinant replication defective adenovirus, Ad.mda-7, has profound antiproliferative and cytotoxic effects in a wide variety of tumor cells but not in nontransformed cells. The studies in this study examined the impact of MDA-7 on RCC proliferation and survival. RCC lines (A498 and UOK121N), but not primary renal epithelial cells, were resistant to adenoviral infection that correlated with a lack of coxsackievirus and adenovirus receptor expression. Additional studies were performed using purified preparations of bacterially synthesized glutathione S-transferase (GST)-MDA-7 protein. GST-MDA-7, but not GST, caused a dose-dependent inhibition of RCC proliferation but not of primary renal epithelial cells. Clinically achievable concentrations of the novel therapeutic agent arsenic trioxide (0.5-1 micro M) were found to have little effect on RCC growth. However, the combination of GST-MDA-7 and arsenic trioxide resulted in a greater than additive reduction in cell growth that correlated with a large increase in tumor cell death. The free radical scavenger N-acetyl cysteine abolished the potentiating effect of arsenic trioxide. Although pro-caspase 3, poly(ADP-ribose) polymerase, and Bcl-(XL) levels, as well as nucleosomal DNA integrity, were reduced by combined treatment, cell killing was predominantly nonapoptotic. Combined treatment of RCC lines with GST-MDA-7 and arsenic trioxide also resulted in a substantial reduction in clonogenic survival compared with either treatment individually. Collectively, these findings demonstrate that MDA-7 protein, in combination with agents that generate free radicals, may have potential in the treatment of RCC.

Acetylcysteine↗
PubMed2003

Linking laboratory and clinical research: the development of molecularly targeted therapeutics inside the national cancer institute center for cancer research.

Understanding the molecular basis of the pathways regulating the cancer cell promises to revolutionize clinical practice. The results of genomic- an proteomic-based studies at the National Cancer Center Institute Center for Cancer Research (NCI CCR) include the indentation of a molecular biomarker for ovarian cancer based on serum proteomic patterns that permits early detection and a new method for the diagnostic and prognostic assessment of subclasses of diffuse large B-cell lymphoma based on molecular criteria. The biological informativeness of molecularly based diagnostic categories confers the additional clinical advantage of identifying molecular pathways that can be selectively targeted for treatment. Molecular profiling of clear cell renal carcinoma, eg, has revealed that it responds to antiangiogenic agents. Moreover, targeted immunomodulatory interventions are proving effective against many cancers. The discovery and development of molecularly based means for detecting, diagnosis, and treating cancer are central priorities of the NCI CCR, which provides an interactive environment encouraging multidisciplinary collaborations, especially among basic and clinical investigators. Its infrastructure supports the iterative flow of information from the bench to the bedside and from the bedside to the bench, expediting the delivery of molecularly based therapeutics to cancer patients.

Antineoplastic Agents↗
PubMed2002

Serum proteomic patterns for detection of prostate cancer.

Pathologic states within the prostate may be reflected by changes in serum proteomic patterns. To test this hypothesis, we analyzed serum proteomic mass spectra with a bioinformatics tool to reveal the most fit pattern that discriminated the training set of sera of men with a histopathologic diagnosis of prostate cancer (serum prostate-specific antigen [PSA] > or =4 ng/mL) from those men without prostate cancer (serum PSA level <1 ng/mL). Mass spectra of blinded sera (N = 266) from a test set derived from men with prostate cancer or men without prostate cancer were matched against the discriminating pattern revealed by the training set. A predicted diagnosis of benign disease or cancer was rendered based on similarity to the discriminating pattern discovered from the training set. The proteomic pattern correctly predicted 36 (95%, 95% confidence interval [CI] = 82% to 99%) of 38 patients with prostate cancer, while 177 (78%, 95% CI = 72% to 83%) of 228 patients were correctly classified as having benign conditions. For men with marginally elevated PSA levels (4-10 ng/mL; n = 137), the specificity was 71%. If validated in future series, serum proteomic pattern diagnostics may be of value in deciding whether to perform a biopsy on a man with an elevated PSA level.

Biomarkers, Tumor↗
PubMed2002

Prospective analysis of circulating endostatin levels in patients with renal cell carcinoma.

BACKGROUND: The aim of the current study was to assess circulating levels of endogenous endostatin in patients with renal carcinoma and to determine the relationship of these levels to circulating levels of vascular endothelial growth factor (VEGF) and prognosis. METHODS: The authors prospectively studied 66 patients (48 male, 18 female; mean age, 50 years) undergoing nephrectomy for renal carcinoma on clinical trials at the National Cancer Institute. Metastases were present in 51 of 66 patients (77%) at the time of nephrectomy. Preoperative and followup serum endostatin and VEGF levels were determined using competitive enzyme immunoassays and compared to a group of 32 age- and gender-matched healthy controls. Associations between circulating endostatin levels and clinicopathologic variables, including survival, were determined. RESULTS: Preoperative endostatin levels were higher in renal carcinoma patients than in healthy controls (P = 0.05). There was a weak to moderate correlation between pretreatment serum endostatin levels and serum VEGF levels (r = 0.47; P = 0.001), and levels of both proteins increased significantly following nephrectomy (P < 0.0001 and P < 0.0001, respectively; n = 41). In addition, patients whose endostatin levels increased more than twofold after nephrectomy had significantly poorer prognoses than patients without such an increase (P = 0.018). This association was more pronounced when patients without metastases were excluded (P = 0.0037). CONCLUSIONS: Circulating endostatin levels are elevated in patients with renal carcinoma and correlate with circulating VEGF levels. Endostatin levels increase after nephrectomy, and patients with the greatest increases experience shortened survival times. These findings suggest an association between tumor aggressiveness and the production of endogenous endostatin in patients with renal carcinoma.

Adult↗
PubMed2002

The RASSF1A tumor suppressor gene is inactivated in prostate tumors and suppresses growth of prostate carcinoma cells.

We analyzed expression status of the recently identified tumor suppressor geneRASSF1A in primary prostate carcinomas and in prostate cell lines. We found complete methylation of the RASSF1A promoter in 63% of primary microdissected prostate carcinomas (7 of 11 samples). The remaining 4 samples (37%) were partially methylated, possibly because of contamination with normal cells. No promoter methylation was observed in matching normal prostate tissues. High levels of RASSF1A transcript and no methylation of RASSF1A promoter were found in explanted primary normal prostate epithelial and stromal cells. Complete silencing and methylation of RASSF1A promoter was observed in five widely used prostate carcinoma cell lines, which acquired the ability to grow in culture spontaneously, including LNCaP, PC-3, ND-1, DU-145, 22Rv1, and one primary prostate carcinoma immortalized by overexpression of the human telomerase catalytic subunit (RC-58T/hTERT). However, no silencing of RASSF1A was found in four other prostate carcinoma cell lines, which were adapted for cell culture after transformation with human papillomaviral DNA. Suppression of cell growth in vitro was demonstrated after the reintroduction of RASSF1A-expressing construct into LNCaP prostate carcinoma cells. Our data implicate the RASSF1A gene in human prostate tumorigenesis.

Cell Division↗
PubMed2002

VHL-mediated hypoxia regulation of cyclin D1 in renal carcinoma cells.

Renal cell carcinoma is associated with mutation of the von Hippel-Lindau (VHL) tumor suppressor gene. Cell lines derived from these tumors cannot exit the cell cycle when deprived of growth factors, and the ability to exit the cell cycle can be restored by the reintroduction of wild-type protein VHL (pVHL). Here, we report that cyclin D1 is overexpressed and remains inappropriately high in during contact inhibition in pVHL-deficient cell lines. In addition, hypoxia increased the expression of cyclin D1 specifically in pVHL-negative cell lines into which pVHL expression was restored. Hypoxic-induction of cyclin D1 was not observed in other pVHL-positive cell lines. This suggests a model whereby in some kidney cell types, pVHL may regulate a proliferative response to hypoxia, whereas the loss of pVHL leads to constitutively elevated cyclin D1 and abnormal proliferation under normal growth conditions.

Carcinoma, Renal Cell↗
PubMed2002

Biochemical diagnosis of pheochromocytoma: which test is best?

CONTEXT: Diagnosis of pheochromocytoma depends on biochemical evidence of catecholamine production by the tumor. However, the best test to establish the diagnosis has not been determined. OBJECTIVE: To determine the biochemical test or combination of tests that provides the best method for diagnosis of pheochromocytoma. DESIGN, SETTING, AND PARTICIPANTS: Multicenter cohort study of patients tested for pheochromocytoma at 4 referral centers between 1994 and 2001. The analysis included 214 patients in whom the diagnosis of pheochromocytoma was confirmed and 644 patients who were determined to not have the tumor. MAIN OUTCOME MEASURES: Test sensitivity and specificity, receiver operating characteristic curves, and positive and negative predictive values at different pretest prevalences using plasma free metanephrines, plasma catecholamines, urinary catecholamines, urinary total and fractionated metanephrines, and urinary vanillylmandelic acid. RESULTS: Sensitivities of plasma free metanephrines (99% [95% confidence interval [CI], 96%-100%]) and urinary fractionated metanephrines (97% [95% CI, 92%-99%]) were higher than those for plasma catecholamines (84% [95% CI, 78%-89%]), urinary catecholamines (86% [95% CI, 80%-91%]), urinary total metanephrines (77% [95% CI, 68%-85%]), and urinary vanillylmandelic acid (64% [95% CI, 55%-71%]). Specificity was highest for urinary vanillylmandelic acid (95% [95% CI, 93%-97%]) and urinary total metanephrines (93% [95% CI, 89%-97%]); intermediate for plasma free metanephrines (89% [95% CI, 87%-92%]), urinary catecholamines (88% [95% CI, 85%-91%]), and plasma catecholamines (81% [95% CI, 78%-84%]); and lowest for urinary fractionated metanephrines (69% [95% CI, 64%-72%]). Sensitivity and specificity values at different upper reference limits were highest for plasma free metanephrines using receiver operating characteristic curves. Combining different tests did not improve the diagnostic yield beyond that of a single test of plasma free metanephrines. CONCLUSION: Plasma free metanephrines provide the best test for excluding or confirming pheochromocytoma and should be the test of first choice for diagnosis of the tumor.

Adolescent↗
PubMed2002

Serial analysis of gene expression in renal carcinoma cells reveals VHL-dependent sensitivity to TNFalpha cytotoxicity.

We have used serial analysis of gene expression (SAGE) to investigate the influence of the von Hippel-Lindau (VHL) gene on global gene expression profiles. SAGE libraries were prepared from renal cell carcinoma (RCC) lines that either lack (parental) or express wild-type VHL (wtVHL). Comparison of these libraries revealed some differentially expressed genes (Glut-1, for example) that were known to be influenced by VHL, but the majority of genes had not previously been reported to be affected by the cell's VHL status. The identification of several genes involved in TNFalpha-mediated events prompted us to compare the sensitivity of cells with different VHL status in TNFalpha cytotoxicity assays. Strikingly, VHL-deficient cells were much more resistant to the toxic influence of TNFalpha. We propose that VHL-dependent sensitization of RCC cells to TNFalpha-mediated killing may contribute to VHL's growth suppressive function.

Blotting, Northern↗
PubMed2002

Determination of a minimal deletion interval on chromosome band 8p21 in sporadic prostate cancer.

Loss of the short arm of chromosome 8 is a common event in prostatic neoplasms. Previous studies indicate that there may be up to three separate tumor suppressor genes on chromosome arm 8p, based on patterns of allelic loss. The responsible gene or genes have yet to be identified. In the present study, we used laser-capture microdissection of primary human prostate tumors and 17 microsatellite markers across chromosome band 8p21 to determine a minimal deletion interval. From an initial set of 120 cases, three tumors contained overlapping interstitial deletions on chromosome band 8p21. The three cases define an internally consistent minimal candidate tumor suppressor gene interval of approximately two megabases.

Chromosome Banding↗
PubMed2002

Proteomic analysis of human prostate cancer.

Proteomics is a promising approach in the identification of proteins and biochemical pathways involved in tumorigenesis. In an effort to discover such proteins and pathways that are deregulated in prostate tumorigenesis, cellular proteomes of matched normal prostate epithelial cells and high-grade prostate cancer cells were analyzed by tissue microdissection, two-dimensional electrophoresis, and mass spectrometry. Forty protein alterations were detected in the tumors; however, the majority of these changes were not shared among the 12 neoplasms. In contrast, parallel cDNA microarray analysis identified a number of common gene expression changes. The marked heterogeneity of the observed protein alterations may have significance with regard to tumor biology and research strategies for molecular profiling analyses of human prostate cancer.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2002

Evaluation of non-formalin tissue fixation for molecular profiling studies.

Using a general strategy for evaluating clinical tissue specimens, we found that 70% ethanol fixation and paraffin embedding is a useful method for molecular profiling studies. Human prostate and kidney were used as test tissues. The protein content of the samples was analyzed by one-dimensional gel electrophoresis, immunoblot, two-dimensional gel electrophoresis, and layered expression scanning. In each case, the fixed and embedded tissues produced results similar to that obtained from snap-frozen specimens, although the protein quantity was somewhat decreased. Recovery of mRNA was reduced in both quantity and quality in the ethanol-fixed samples, but was superior to that obtained from formalin-fixed samples and sufficient to perform reverse transcription polymerase chain reactions. Recovery of DNA from ethanol-fixed specimens was superior to formalin-fixed samples as determined by one-dimensional gel electrophoresis and polymerase chain reaction. In conclusion, specimens fixed in 70% ethanol and embedded in paraffin produce good histology and permit recovery of DNA, mRNA, and proteins sufficient for several downstream molecular analyses. Complete protocols and additional discussion of relevant issues are available on an accompanying website (http://cgap-mf.nih.gov/).

Actins↗
PubMed2002

The contribution of VHL substrate binding and HIF1-alpha to the phenotype of VHL loss in renal cell carcinoma.

Clear-cell renal carcinoma is associated with inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene. VHL is the substrate recognition subunit of an E3 ligase, known to target the alpha subunits of the HIF heterodimeric transcription factor for ubiquitin-mediated degradation under normoxic conditions. We demonstrate that competitive inhibition of the VHL substrate recognition site with a peptide derived from the oxygen degradation domain of HIF1alpha recapitulates the tumorigenic phenotype of VHL-deficient tumor cells. These studies prove that VHL substrate recognition is essential to the tumor suppressor function of VHL. We further demonstrate that normoxic stabilization of HIF1alpha alone, while capable of mimicking some aspects of VHL loss, is not sufficient to reproduce tumorigenesis, indicating that it is not the critical oncogenic substrate of VHL.

Animals↗