Germline and somatic mutations in the tyrosine kinase domain of the MET proto-oncogene in papillary renal carcinomas.

Hereditary papillary renal carcinoma (HPRC) is a recently recognized form of inherited kidney cancer characterized by a predisposition to develop multiple, bilateral papillary renal tumours. The pattern of inheritance of HPRC is consistent with autosomal dominant transmission with reduced penetrance. HPRC is histologically and genetically distinct from two other causes of inherited renal carcinoma, von Hippel-Lindau disease (VHL) and the chromosome translocation (3;8). Malignant papillary renal carcinomas are characterized by trisomy of chromosomes 7, 16 and 17, and in men, by loss of the Y chromosome. Inherited and sporadic clear cell renal carcinomas are characterized by inactivation of both copies of the VHL gene by mutation, and/or by hypermethylation. We found that the HPRC gene was located at chromosome 7q31.1-34 in a 27-centimorgan (cM) interval between D7S496 and D7S1837. We identified missense mutations located in the tyrosine kinase domain of the MET gene in the germline of affected members of HPRC families and in a subset of sporadic papillary renal carcinomas. Three mutations in the MET gene are located in codons that are homologous to those in c-kit and RET, proto-oncogenes that are targets of naturally-occurring mutations. The results suggest that missense mutations located in the MET proto-oncogene lead to constitutive activation of the MET protein and papillary renal carcinomas.

Novel mutations in FH and expansion of the spectrum of phenotypes expressed in families with hereditary leiomyomatosis and renal cell cancer.

BACKGROUND: Hereditary leiomyomatosis and renal cell cancer (HLRCC; OMIM 605839) is the predisposition to develop smooth muscle tumours of the skin and uterus and/or renal cancer and is associated with mutations in the fumarate hydratase gene (FH). Here we characterise the clinical and genetic features of 21 new families and present the first report of two African-American families with HLRCC. METHODS: Using direct sequencing analysis we identified FH germline mutations in 100% (21/21) of new families with HLRCC. RESULTS: We identified 14 germline FH mutations (10 missense, one insertion, two nonsense, and one splice site) located along the entire length of the coding region. Nine of these were novel, with six missense (L89S, R117G, R190C, A342D, S376P, Q396P), one nonsense (S102X), one insertion (111insA), and one splice site (138+1G>C) mutation. Four unrelated families had the R58X mutation and five unrelated families the R190H mutation. Of families with HLRCC, 62% (13/21) had renal cancer and 76% (16/21) cutaneous leiomyomas. Of women FH mutation carriers from 16 families, 100% (22/22) had uterine fibroids. Our study shows that expression of cutaneous manifestations in HLRCC ranges from absent to mild to severe cutaneous leiomyomas. FH mutations were associated with a spectrum of renal tumours. No genotype-phenotype correlations were identified. CONCLUSIONS: In combination with our previous report, we identify 31 different germline FH mutations in 56 families with HLRCC (20 missense, eight frameshifts, two nonsense, and one splice site). Our FH mutation detection rate is 93% (52/56) in families suspected of HLRCC.

Decreased expression of the pro-apoptotic protein Par-4 in renal cell carcinoma.

Par-4 is a widely expressed leucine zipper protein that confers sensitization to apoptosis induced by exogenous insults. Because the expression of genes that promote apoptosis may be down-regulated during tumorigenesis, we sought to examine the expression of Par-4 in human tumors. We present here evidence that Par-4 protein levels were severely decreased in human renal cell carcinoma specimens relative to normal tubular cells. Replenishment of Par-4 protein levels in renal cell carcinoma cell lines conferred sensitivity to apoptosis. Because apoptosis may serve as a defense mechanism against malignant transformation or progression, decreased expression of Par-4 may contribute to the pathophysiology of renal cell carcinoma.

Low molecular weight proteomic information distinguishes metastatic from benign pheochromocytoma.

Metastatic lesions occur in up to 36% of patients with pheochromocytoma. Currently there is no way to reliably detect or predict which patients are at risk for metastatic pheochromocytoma. Thus, the discovery of biomarkers that could distinguish patients with benign disease from those with metastatic disease would be of great clinical value. Using surface-enhanced laser desorption ionization protein chips combined with high-resolution mass spectrometry, we tested the hypothesis that pheochromocytoma pathologic states can be reflected as biomarker information within the low molecular weight (LMW) region of the serum proteome. LMW protein profiles were generated from the serum of 67 pheochromocytoma patients from four institutions and analyzed by two different bioinformatics approaches employing pattern recognition algorithms to determine if the LMW component of the circulatory proteome contains potentially useful discriminatory information. Both approaches were able to identify combinations of LMW molecules which could distinguish all metastatic from all benign pheochromocytomas in a separate blinded validation set. In conclusion, for this study set low molecular mass biomarker information correlated with pheochromocytoma pathologic state using blinded validation. If confirmed in larger validation studies, efforts to identify the underlying diagnostic molecules by sequencing would be warranted. In the future, measurement of these biomarkers could be potentially used to improve the ability to identify patients with metastatic disease.

Suramin: a novel growth factor antagonist with activity in hormone-refractory metastatic prostate cancer.

PURPOSE: Suramin is known to inhibit the growth of malignant prostate carcinoma cells in vitro. This led us to evaluate the effectiveness of suramin in the treatment of 38 patients with prostate carcinoma refractory to hormone therapy. PATIENTS AND METHODS: Suramin was administered by continuous infusion at a rate designed to reach a peak of 300 micrograms/mL at the end of 14 days. Patients were given 8 weeks to recover from any toxicity before beginning the second cycle. Subsequent cycles were administered in the same manner except the starting dose rate was 280 mg/m2. RESULTS: In 17 patients with measurable soft tissue disease, three had complete disappearance of soft tissue disease for 4, 5, and 11 months, whereas three patients had a greater than or equal to 50% decrease in the sum of the products of the diameters of all measurable disease for greater than or equal to 1 month. Of these 17 patients, pretreatment prostate-specific antigen (PSA) decreased by 75% or more in five (29%) and normalized in one (6%). The remaining 21 patients had disease limited to bone, and only one of these experienced resolution of more than 50% of all lesions on bone scan. Of these 21 patients, pretreatment PSA decreased by 75% or more in eight (38%) and normalized in five (25%). Median time to progression for all patients was 26.3 weeks, and median survival was 42.3 weeks. Patients with bone involvement alone exhibited a better survival than patients with soft tissue involvement (P2 = .02). Survival was strongly correlated (P2 = .0001) with a decline in the pretreatment PSA of greater than or equal to 75% by the eighth week on therapy, with nearly an 85% survival at 1 year compared with a 20% survival for those whose pretreatment PSA did not decline by that amount. CONCLUSION: We conclude that suramin is an active agent in hormone-refractory prostate carcinoma.

Distinct gene expression profiles in norepinephrine- and epinephrine-producing hereditary and sporadic pheochromocytomas: activation of hypoxia-driven angiogenic pathways in von Hippel-Lindau syndrome.

Pheochromocytomas in von Hippel-Lindau (VHL) syndrome produce exclusively norepinephrine, whereas those in multiple endocrine neoplasia type 2 (MEN 2) produce epinephrine. This study examined the pathways activated in VHL-associated pheochromocytomas by comparing gene expression profiles in VHL and MEN 2 tumors in relationship to profiles in sporadic norepinephrine- and epinephrine-producing tumors. Larger and more distinct differences in gene expression among hereditary than sporadic tumors indicated the importance of the underlying mutation to gene expression profiles. Many of the genes over-expressed in VHL compared with MEN 2 tumors were clearly linked to the hypoxia-driven angiogenic pathways that are activated in VHL-associated tumorigenesis. Such genes included those for the glucose transporter, vascular endothelial growth factor (VEGF), placental growth factor, angiopoietin 2, tie-1, VEGF receptor 2 and its coreceptor, neuropilin-1. Other up-regulated genes, such as connective tissue growth factor, cysteine-rich 61, matrix metalloproteinase 1, vascular endothelial cadherin, tenascin C, stanniocalcin 1, and cyclooxygenases 1 and 2 are known to be involved in VEGF-regulated angiogenesis. Shared differences in expression of subsets of genes in norepinephrine- versus epinephrine-producing hereditary and sporadic pheochromocytomas indicated other differences in gene expression that may underlie the biochemical phenotype. Over-expression of the hypoxia-inducible transcription factor, HIF-2alpha, in norepinephrine-predominant sporadic and VHL tumors compared with epinephrine-producing tumors indicates that expression of this gene depends on the noradrenergic biochemical phenotype. The findings fit with the known expression of HIF-2alpha in norepinephrine-producing cells of the sympathetic nervous system and might explain both the development and noradrenergic biochemical phenotype of pheochromocytomas in VHL syndrome.

Suramin inhibits bone resorption and reduces osteoblast number in a neonatal mouse calvarial bone resorption assay.

The antineoplastic properties of suramin, a polyanionic agent with demonstrated antigrowth factor activity, are under evaluation in vitro, in vivo, and in clinical trials. Suramin has been shown to have antitumor activity in patients with advanced, hormone refractory prostate cancer. During these trials, significant resolution of osseous pain was observed in nearly three quarters of the patients treated with suramin. To evaluate the effect of suramin on bone cells, we studied the effect of suramin on bone resorption in a neonatal mouse calvarial assay. Suramin inhibited bone-resorbing activity in a dose-related fashion and had an additive effect with calcitonin. Calvaria pretreated with suramin had less bone-resorbing activity, fewer attached osteoblasts, and less medium alkaline phosphatase activity than control calvaria. Suramin also inhibited osteoclastic release of tritiated proline from labeled bone in a dose-dependent fashion. The effect of metastatic prostate carcinoma on bone is incompletely understood, but may be moderated by tumor-produced factors and/or cytokines. The effects of several such agents, therefore, were examined in combination with suramin. Bone resorption induced by PTH, epidermal growth factor, tumor necrosis factor, and a tumor-produced factor, PTH related-protein, was blocked by suramin. The ability of suramin to inhibit the bone-resorbing effects of several cytokines suggests that its mechanism may involve direct action on bone metabolism. Autoradiography performed on calvaria treated with labeled suramin demonstrated heavy deposition of suramin on the outer surface of the matrix, adjacent to osteoblasts and osteoclasts lining the outer table, suggesting that bone cells may be subject to high local concentrations of the drug, in keeping with this hypothesis.

Predictive value of preoperative tests in discriminating bilateral adrenal hyperplasia from an aldosterone-producing adrenal adenoma.

In primary hyperaldosteronism, discriminating bilateral adrenal hyperplasia (BAH) from an aldosterone-producing adenoma (APA) is important because adrenalectomy, which is usually curative in APA, is seldom effective in BAH. We analyzed the results from our most recent 7-yr series to evaluate the predictive value of preoperative noninvasive tests compared with adrenal vein sampling (AVS). Forty-eight patients with hypertensive hyperaldosteronism underwent bedside testing, computed tomography (CT) imaging, and AVS. Those in whom the results of AVS indicated APA underwent adrenalectomy. Twelve (30%) and 14 (34%) of 41 patients with APA had paradoxical falls with ambulation in plasma aldosterone concentration (PAC) and 18-hydroxycorticosterone (18-OH-B), respectively. Twenty-nine (70%) and 26 (65%) APA patients had a rise in PAC and 18-OH-B, respectively, as did all 8 BAH patients. Significant identifiers of BAH were supine PAC values less than 15 ng/dL (P: = 0.04), an increase greater than 60% (P: = 0.02) in PAC with ambulation, and supine 18-OH-B values less than 60 ng/dL (P: = 0.04). CT imaging alone was not predictive for BAH or APA. In our population, patients with a positive bedside test result (e.g. a fall in PAC and/or 18-OH-B) and a unilateral adrenal nodule on CT (10 of 41 patients) could have proceeded directly to adrenalectomy for APA. However, a positive bedside test result with a negative CT or a negative bedside test result regardless of CT findings required AVS to confirm the diagnosis and site of disease.

Pheochromocytomas in von Hippel-Lindau syndrome and multiple endocrine neoplasia type 2 display distinct biochemical and clinical phenotypes.

This study examined the mechanisms linking different biochemical and clinical phenotypes of pheochromocytoma in multiple endocrine neoplasia type 2 (MEN 2) and von Hippel-Lindau (VHL) syndrome to underlying differences in the expression of tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis, and of phenylethanolamine N-methyltransferase (PNMT), the enzyme that converts norepinephrine to epinephrine. Signs and symptoms of pheochromocytoma, plasma catecholamines and metanephrines, and tumor cell neurochemistry and expression of TH and PNMT were examined in 19 MEN 2 patients and 30 VHL patients with adrenal pheochromocytomas. MEN 2 patients were more symptomatic and had a higher incidence of hypertension (mainly paroxysmal) and higher plasma concentrations of metanephrines, but paradoxically lower total plasma concentrations of catecholamines, than VHL patients. MEN 2 patients all had elevated plasma concentrations of the epinephrine metabolite, metanephrine, whereas VHL patients showed specific increases in the norepinephrine metabolite, normetanephrine. The above differences in clinical presentation were largely explained by lower total tissue contents of catecholamines and expression of TH and negligible stores of epinephrine and expression of PNMT in pheochromocytomas from VHL than from MEN 2 patients. Thus, mutation-dependent differences in the expression of genes controlling catecholamine synthesis represent molecular mechanisms linking the underlying mutation to differences in clinical presentation of pheochromocytoma in patients with MEN 2 and the VHL syndrome.

Iodine-131-metaiodobenzylguanidine scintigraphy in preoperative and postoperative evaluation of paragangliomas: comparison with CT and MRI.

Iodine-131-metaiodobenzylguanidine (MIBG) scintigraphy, transmission computed tomography and magnetic resonance imaging were used to evaluate 36 patients with clinically suspected functioning paragangliomas. The patients were divided into two groups. In Group 1 (n = 21), studied before surgery, patients mainly had benign adrenal disease. In Group 2 (n = 15), studied after surgery, patients frequently had malignant or extra-adrenal tumors. In Group 1, transmission computed tomography and magnetic resonance imaging were more sensitive (100% for both) than MIBG scintigraphy (82%), which, however, was the most specific (100%). In Group 2, MIBG scintigraphy and magnetic resonance imaging were more sensitive (83% for both) than transmission computed tomography (75%), but MIBG was again the most specific (100%). Thus, all three were complementary modalities for localizing paragangliomas both preoperatively and postoperatively. MIBG imaging is indicated for both groups but it is especially recommended for postsurgical patients with recurrence because the disease is often malignant or extra-adrenal.

Clinical and genetic analysis of patients with pancreatic neuroendocrine tumors associated with von Hippel-Lindau disease.

BACKGROUND: Patients with von Hippel-Lindau disease (VHL) may develop pancreatic neuroendocrine tumors (PNETs), which can behave in a malignant fashion. We prospectively evaluated size criteria for resection of lesions and the role of genotype/phenotype analysis of germline VHL mutations in predicting clinical course. METHODS: From December 1988 through December 1999 we screened 389 patients with VHL. The diagnosis of PNET was made by pathologic analysis of tissues or by radiographic appearance. Germline mutations were determined by quantitative Southern blotting, fluorescence in situ hybridization and complete gene sequencing. RESULTS: Forty-four patients with PNETs have been identified; 25 have undergone surgical resection, 5 had metastatic disease, and 14 are being monitored. No patient who has undergone resection based on tumor size criteria has developed metastases. Patients with PNETs were more likely to have missense mutations (58%), and 4 of 5 patients (80%) with metastatic disease had mutations in exon 3 compared with 18 of 39 (46%) patients without metastatic disease. CONCLUSIONS: Imaging for detection and surgical resection based on size criteria have resulted in the successful management of VHL patients with PNETs. Analysis of germline mutations may help identify patients at risk for PNET and which patients may benefit from surgical intervention.

Cutaneous horn of penis.

Cutaneous horns of the penis are hyperkeratotic lesions of the skin which arise secondary to chronic irritation. Treatment is local excision with removal of a broad base. Examination of the base is important to rule out carcinoma as the underlying cause of the lesion. A case report is presented and the literature reviewed.

Transvenous occlusion of clinical and subclinical varicoceles.

Forty-four subfertile men with a palpable or clinically suspected varicocele underwent physical examination, nuclear scan, and testicular venography. The ability of these tests to detect a varicocele was compared. The sensitivity of physical examination was 0.94 on the left and 0.35 on the right. Specificity was 0.22 on the left and 0.77 on the right. The sensitivity of nuclear scan was 0.97 on the left and 0.73 on the right. Specificity was 0.56 on the left and 0.50 on the right. Patients with varicoceles demonstrated by venography were treated with testicular vein embolization. There were no complications except two asymptomatic subintimal injections, both of which occurred on the right side. A total of 19 patients had pre- and post-embolization semen analyses performed. The total motile sperm count increased from 27.0 million to 35.5 million. The overall pregnancy rate in the embolization-treated group was 43.7 percent.

Splenic gonadal fusion.

Splenogonadal fusion is a rare anomaly to be included in the differential diagnosis of testicular masses. It is often associated with congenital defects, including peromelia and micrognathia. A case is presented and the literature reviewed.

Perirenal myelolipoma.

Extra-adrenal myelolipomas are rare, benign tumors composed of hematopoietic and adipose elements. Although these tumors can cause local symptoms or hemorrhage, they are generally asymptomatic. However, when discovered intraoperatively, they pose a diagnostic dilemma to the urologic surgeon. We present a case of perirenal extra-adrenal myelolipoma discovered intraoperatively in a patient with von Hippel-Lindau disease undergoing partial nephrectomy.

Laparoscopic cytoreductive nephrectomy as preparation for administration of systemic interleukin-2 in the treatment of metastatic renal cell carcinoma: a pilot study.

OBJECTIVES: Cytoreductive nephrectomy is commonly performed in patients with metastatic renal cell carcinoma before systemic interleukin-2 (IL-2) therapy. Open nephrectomy is associated with prolonged recovery during which metastatic disease can progress. The feasibility of laparoscopic cytoreductive surgery in these patients with large renal tumors was examined. The role of tumor morcellation in reducing the recovery period and allowing earlier treatment with IL-2 was investigated. METHODS: Patients with metastatic renal cancer underwent either open nephrectomy (group 1, n = 19) or laparoscopic cytoreductive nephrectomy (n = 11; 6 with tumor morcellation [group 2], 5 with removal of the tumor through a small incision [group 3]). The three groups were compared to evaluate relative recovery, suitability for treatment with IL-2, and laparoscopic port site seeding. RESULTS: A group of 19 patients underwent open nephrectomy (group 1). Eleven patients with a median tumor volume of 377 cm3 (median tumor diameter 9 cm) underwent laparoscopic cytoreductive nephrectomy. Six of these patients underwent tumor morcellation (group 2) and 5 underwent laparoscopic assisted nephrectomy (group 3). There was no difference in patient age, sex, sites of metastatic disease, ECOG status, size of renal tumor, or surgical complication rates among groups. Patients whose tumor was morcellated had reduced postoperative parenteral narcotic requirements and were discharged sooner than patients undergoing open cytoreductive nephrectomy. Time to treatment with IL-2 was shortest in the morcellation group (median time to treatment 37 days). No port site seeding was observed. CONCLUSIONS: Laparoscopic cytoreductive nephrectomy in patients with bulky renal disease is a safe procedure in selected patients. This pilot study demonstrated a significant association of laparoscopic tumor morcellation with less postoperative pain, faster time to discharge, and shorter time to treatment with IL-2. A randomized study is warranted to determine the role of laparoscopic cytoreductive nephrectomy with tumor morcellation.

Bladder calcifications after photodynamic therapy: analysis of a rare complication.

OBJECTIVES: We analyzed bladder calcifications occurring after photodynamic therapy administered for the treatment of superficial bladder cancer, a finding not previously reported after this treatment. METHODS: Bladder biopsies from 20 patients undergoing photodynamic therapy were evaluated. Bladder calcifications were identified in 2 patients and analyzed for composition. RESULTS: One patient had diffuse microcrystalline deposition in two biopsies composed of calcium oxalate monohydrate A. A second patient had a focal stone at a healing biopsy site composed of monoclinic calcium hydrogen phosphate dihydrate (brushite) (66%), calcium oxalate (25%), hydroxyapatite (6%), and protein (3%). CONCLUSIONS: Rare calcium oxalate and brushite calcifications were identified after photodynamic therapy and presumed to occur because of tissue injury associated with treatment.

Cytoreductive surgery prior to interleukin-2-based therapy in patients with metastatic renal cell carcinoma.

From May 1985 to December 1990, 93 patients with the clinical diagnosis of metastatic renal cell carcinoma and their primary tumor in place were evaluated for cytoreductive surgery as preparation for systemic therapy with regimens based on interleukin-2. These patients had typical sites of metastatic disease and manifestations of paraneoplastic syndromes. Patients underwent removal of the primary tumor, as well as debulking when this could be performed safely. Thirty-two percent of patients (30/93) had a second surgical resection in addition to their nephrectomy, frequently because of the large size of the primary tumor and its invasion of adjacent structures. Thirteen percent of patients (12/93) experienced postoperative complications. There were no perioperative mortalities. Forty percent of patients (37/93) who underwent nephrectomy could not be treated with immunotherapy, usually because of progression of disease. A preoperative ECOG status greater than or equal to 2 was the only significant risk factor associated with failure to undergo immunotherapy (P = 0.043). The response rate to immunotherapy in the 56 patients receiving interleukin-2 was 27 percent (4 CR, 11 PR).

Epididymal cystadenomas in von Hippel-Lindau disease.

OBJECTIVES: Epididymal cystadenomas (ECs) are frequently found in association with von Hippel-Lindau disease (VHL), but little has been reported about their sonographic appearance. We review the sonographic appearance of ECs, the relationship of ECs to other manifestations of VHL, and the specific genetic mutations associated with ECs. METHODS: Fifty-six male patients with VHL were examined with scrotal sonography and physical examination as part of a larger screening program for VHL. The head of the epididymis was measured in two planes on sonography and compared with age-matched normal controls. All VHL patients with palpable epididymal abnormalities or enlargement (more than two standard deviations) of the head of the epididymis on ultrasound were considered positive for EC. RESULTS: Thirty of 56 (54%) male patients with VHL demonstrated a unilateral (n = 10; 33%) or bilateral (n = 20; 67%) solid abnormality in the head of the epididymis suggestive of EC. Sonographic appearances ranged from a solid mass with multiple tiny cysts to an almost completely solid mass. The most common appearance was a 15- to 20-mm solid mass with small cystic components. Dilated efferent ductules were seen within the testicle in 7 men, evidently a result of chronic obstruction. There was no association between the clinical subtype of VHL and the presence of ECs (P > 0.10, chi square). Mutations resulting in a truncated gene product were associated with the development of ECs but the association did not reach statistical significance (P = 0.06). CONCLUSIONS: ECs are a common manifestation of VHL in men and exhibit a range of appearances on ultrasound. Sonography can be used to identify ECs and determine the extent of cystic dilation of the rete testes. The benign course of ECs and the usual absence of clinical symptoms favor a conservative approach to their management.

Progelatinase A mRNA expression in cell lines derived from tumors in patients with metastatic renal cell carcinoma correlates inversely with survival.

OBJECTIVES: Tumors are thought to metastasize by a process involving tumor cell attachment to extracellular matrix, degradation of matrix components by tumor-associated proteases, and cellular movement into the area modified by protease activity. Type IV collagen comprises the major element tumor cells must degrade to gain access to the rest of the body. Renal cancer cell line progelatinase A (E.C. 3.4.24.24; 72-kDa type IV collagenase; MMP-2) mRNA expression was correlated with patient survival. METHODS: Total cellular mRNA was extracted from tumor cell lines derived from patients with metastatic renal cell carcinoma. The results of the densitometric analysis of Northern blots were correlated with patient survival. Formalin-fixed, paraffin-embedded tissue sections of primary renal cancers were examined for immunohistochemical expression of MMP-2. RESULTS: Cell lines established from 23 primary renal tumors and six metastatic sites in 26 patients with metastatic renal carcinoma were studied. Variable expression of progelatinase A, relative to A2058 melanoma cells (mean +/- SEM, 0.60 +/- 0.21; median, 0.082; range, 0 to 4.78), was found. There was a significant inverse association between patient survival and the log of the MMP-2 expression (P = 0.045 by the Cox proportional-hazards model). Using a cutoff value of 0.10, the closest round number to the median expression of MMP-2, a significant difference between survival of patients with lower and higher MMP-2 expression in their primary renal cell line was found (P = 0.0054). Cell lines with low, intermediate, and high expression of MMP-2 mRNA all had primary tumors with high tissue immunohistochemical expression of MMP-2. CONCLUSIONS: These studies demonstrate an inverse relationship between renal cancer cell line MMP-2 mRNA expression and patient survival. Immunohistochemical studies of the primary tumors from which the cell lines were derived uniformly showed high MMP-2 expression. Previous work suggests local renal factors upregulate cellular expression of MMP-2 in the primary tumor, and are not active at extrarenal sites.