Biomedical subjects

W M Linehan

Publications and source records attributed to W M Linehan.

At least 91 records · Page 5Linked to original sources

PubMed1998

Improved detection of germline mutations in the von Hippel-Lindau disease tumor suppressor gene.

von Hippel-Lindau disease (VHL) is an inherited neoplastic disorder characterized by the development of tumors in the eyes, brain, spinal cord, inner ear, adrenal gland, pancreas, kidney, and epididymis. The VHL tumor suppressor gene was identified in 1993. Initial studies reported the detection of germline mutations in the VHL gene in 39-75% of VHL families. We used tests that detect different types of mutations to improve the frequency of detection of germline mutations in VHL families. The methods included quantitative Southern blotting to detect deletions of the entire VHL gene, Southern blotting to detect gene rearrangements, fluorescence in situ hybridization (FISH) to confirm deletions, and complete sequencing of the gene. Here we report that we have detected germline mutations in the VHL gene in 100% (93/93) of VHL families tested. In addition, we describe 13 novel intragenic VHL germline mutations. With the methodology described in this article, it is now possible to identify germline mutations in virtually all families with VHL.

Blotting, Southern↗

PubMed1998

Multiple neuroendocrine tumors of the pancreas in von Hippel-Lindau disease patients: histopathological and molecular genetic analysis.

Although pancreatic neuroendocrine tumors (NETs) in von Hippel-Lindau (VHL) disease have been reported, their pathological features have not been characterized. In addition, it is unknown whether alterations of the VHL gene are responsible for pancreatic NET development. To evaluate NETs in VHL patients, we performed histopathological analysis of 30 pancreatic tumors in 14 patients. In addition, DNA from NETs and normal pancreatic tissue from 6 patients with documented germ-line VHL gene mutations was studied for allelic deletions of the second copy of the VHL gene by fluorescence in situ hybridization and polymerase chain reaction-based single-strand conformational polymorphism analysis. Morphologically, the tumors were characterized by solid, trabecular, and/or glandular architecture and prominent stromal collagen bands. Sixty percent of the tumors revealed at least focally clear-cell cytology. All tumors were positive for panendocrine immunohistochemistry markers (chromogranin A and/or synaptophysin); 35% of NETs demonstrated focal positivity for pancreatic polypeptide, somatostatin, insulin, and/or glucagon; and no immunostaining for pancreatic and gastrointestinal hormones was observed in 65% of tumors. Dense core neurosecretory granules were evident by electron microscopic examination, and the clear cells additionally revealed abundant intracytoplasmic lipid. All NETs that were subjected to genetic analysis showed allelic loss of the second copy of the VHL gene. We conclude that multiple, nonfunctional pancreatic NETs occur in VHL patients. Stromal collagen bands and clear-cell morphology are important histological features of VHL-associated NETs. The presence of allelic deletions of the VHL gene in pancreatic NETs provides direct molecular evidence for a role of the gene in their tumorigenesis and establishes NET as an independent tumor type of VHL disease.

Adolescent↗

PubMed1998

Familial renal oncocytoma: clinicopathological study of 5 families.

PURPOSE: We analyzed familial renal oncocytoma to provide a foundation for studies aimed at defining genes involved in the pathogenesis of renal oncocytoma. MATERIALS AND METHODS: We describe 5 families with multiple members affected with renal oncocytoma. Tumors were analyzed pathologically, and affected and nonaffected members were screened clinically and genetically. RESULTS: We identified 12 affected male and 3 affected female (ratio 4:1) individuals in the 5 families. In affected family members renal oncocytomas were often multiple and bilateral. No metastatic disease was observed. Most renal oncocytomas were detected incidentally in asymptomatic individuals or during screening of asymptomatic members of renal oncocytoma families. One identical twin pair was affected with bilateral multiple renal oncocytomas. CONCLUSIONS: Renal oncocytoma may be inherited in some families.

Adenoma, Oxyphilic↗

PubMed1998

Trisomy 7-harbouring non-random duplication of the mutant MET allele in hereditary papillary renal carcinomas.

The gene defect for hereditary papillary renal carcinoma (HPRC) has recently been mapped to chromosome 7q, and germline mutations of MET (also known as c-met) at 7q31 have been detected in patients with HPRC (ref. 2). Tumours from these patients commonly show trisomy of chromosome 7 when analysed by cytogenetic studies and comparative genomic hybridization (CGH). However, the relationship between trisomy 7 and MET germline mutations is not clear. We studied 16 renal tumours from two patients with documented germline mutations in exon 16 of MET. Fluorescent in situ hybridization (FISH) analysis showed trisomy 7 in all tumours. To determine whether the chromosome bearing the mutant or wild-type MET gene was duplicated, we performed duplex PCR and phosphoimage densitometry using polymorphic microsatellite markers D7S1801 and D7S1822, which were linked to the disease gene locus, and D1S1646 as an internal control. We determined the parental origin of chromosome alleles by genotyping parental DNA. In all 16 tumours there was an increased signal intensity (2:1 ratio) of the microsatellite allele from the chromosome bearing the mutant MET compared with the allele from the chromosome bearing the wild-type MET. Our study demonstrates a non-random duplication of the chromosome bearing the mutated MET in HPRC and implicates this event in tumorigenesis.

Adult↗

PubMed1998

Pancreatic neuroendocrine tumors associated with von Hippel Lindau disease: diagnostic and management recommendations.

BACKGROUND: von Hippel Lindau disease (VHL) is an inherited syndrome characterized by tumors of the kidney, adrenal, central nervous system, and pancreas. The incidence and natural history of pancreatic neuroendocrine tumors occurring in VHL are not known. METHODS: From December 1988 through November 1997, 256 patients with VHL were screened with imaging studies, and these data were reviewed from a prospective database. RESULTS: Thirty (12%) of 256 patients had solid pancreatic lesions consistent with neuroendocrine tumors. Fourteen patients underwent resection, and 4 with metastases on imaging studies underwent biopsy only. Of the 14 patients who underwent resection, 11 remain free of disease, 2 have experienced recurrence, and 1 has died of unrelated causes (mean follow-up, 25 months; range, 3 to 73 months). The size of the primary tumor (median, 5 cm; range, 3 to 8 cm) in patients with liver metastases was significantly larger than the size of the primary tumor (median, 2 cm; range, 1 to 5 cm) in patients without liver metastases (P = .0013). CONCLUSIONS: Solid pancreatic lesions were detected in 12% of patients with VHL. Larger primary tumors were associated with liver metastases. Pancreatic imaging to identify neuroendocrine tumors and resection when they reach 2 to 3 cm may prevent the development of hepatic metastases.

Adolescent↗

PubMed1998

Serum interleukin-6 levels in metastatic renal cell carcinoma before treatment with interleukin-2 correlates with paraneoplastic syndromes but not patient survival.

PURPOSE: We sought to determine the frequency of interleukin-6 (IL-6) expression in renal cancer cell lines, the frequency of the detection of IL-6 in the serum of patients with metastatic renal cell carcinoma, whether serum IL-6 level correlates with the development of paraneoplastic syndromes and whether serum IL-6 level in patients with metastatic renal cancer correlates with response to treatment with interleukin-2 (IL-2) or patient survival. MATERIALS AND METHODS: Conditioned media from 21 cell lines from 20 patients were examined for IL-6. We identified 2 matched groups of patients with metastatic renal cancer (30 responders and 29 nonresponders) to IL-2 based immunotherapy. Stored pretreatment serum specimens were evaluated for IL-6. Medical records were reviewed to determine the presence of paraneoplastic syndromes. RESULTS: IL-6 was detected in 19 of 21 renal cancer cell lines (90%) obtained from 20 patients with metastatic renal cancer as well as in the serum of 33 of 59 patients (56%) with metastatic renal cell carcinoma. A significant association between serum IL-6 level and anemia (p = 0.0032), elevated platelet count (p = 0.01), decreased albumin (p = 0.034) and elevated alkaline phosphatase (p = 0.04) was found. A trend was noted of the association of increased serum IL-6 level and fever (p = 0.051). No correlation was found between pretreatment serum IL-6 level and survival or response to IL-2. CONCLUSIONS: IL-6 was frequently secreted by renal cancer cell lines but it was only present in the serum of approximately half of the patients with metastatic renal cancer. Elevations of serum IL-6 were associated with paraneoplastic manifestations frequently seen in patients with renal cancer, including anemia, thrombocytosis, decreased albumin and elevations of alkaline phosphatase (Stauffer's syndrome). A weak relationship was noted between serum IL-6 level and fever but none was noted between that and survival or response to IL-2.

Adult↗

PubMed1998

Pseudotumors after renal parenchymal sparing surgery.

PURPOSE: After renal parenchymal sparing surgery, residual defects may persist on imaging studies at the sites of resection. These "pseudotumors" may lead to confusion as to whether a lesion was removed or has recurred. We describe the imaging appearances and behavior of renal pseudotumors following renal parenchymal sparing surgery. MATERIALS AND METHODS: From 1988 to 1997, 32 patients underwent 46 renal parenchymal sparing surgeries for removal of renal cancers, including von Hippel-Lindau disease in 27, hereditary papillary renal cancer in 2 and sporadic disease in 3. A median of 14 tumors (range 1 to 114) were removed in each operation. Thrombin soaked absorbable gelatin sponge was placed in the tumor bed after resection to aid hemostasis. We reviewed all imaging studies performed after these operations to characterize these lesions and gain further understanding into the prevalence and etiology. RESULTS: Of the patients, 9 had a total 13 pseudotumors on initial postoperative imaging studies, including Hippel-Lindau disease in 7, hereditary papillary renal cancer in 1 and sporadic renal cancer in 1. Pseudotumors were observed after 10 of 46 operations (22%). All pseudotumors demonstrated round contours and enhancement after contrast media, simulating a tumor, yet, these lesions resolved in a mean of 13 months, leaving only small cortical scars. CONCLUSIONS: Renal pseudotumors are commonly seen after renal parenchymal sparing surgery and should not be confused with residual or recurrent disease. Enhancement is likely due to granulation tissue involving the lattice of absorbable gelatin sponge. These lesions usually resolve within a year but can take longer to do so.

Adult↗

PubMed1998

Phase II study of suramin plus aminoglutethimide in two cohorts of patients with androgen-independent prostate cancer: simultaneous antiandrogen withdrawal and prior antiandrogen withdrawal.

Management of prostate cancer progression after failure of initial hormonal therapy is controversial. Recently, the activity of the simple discontinuation of antiandrogen therapy has been established by several groups, as well as the enhanced activity when combined with adrenal suppression (i.e., aminoglutethimide and hydrocortisone). Furthermore, suramin has generated considerable interest following reports of response rates ranging from 17 to 70%. More recently, suramin response rates of 18 and 22% have been reported when the potential confounding variables of flutamide withdrawal and hydrocortisone were prospectively controlled. On the basis of the activity of combining aminoglutethimide with flutamide withdrawal, we designed a protocol in which suramin was combined with aminoglutethimide in two cohorts of patients (those with simultaneous antiandrogen withdrawal compared to those who had previously discontinued antiandrogen therapy). Eighty-one evaluable patients were enrolled in this study between June 1992 and November 1994. Patients were a priori divided into two cohorts, those receiving prior antiandrogen withdrawal (n = 56) and those receiving simultaneous antiandrogen withdrawal (n = 25) at the time the patients were enrolled into the trial. For the group that discontinued antiandrogen prior to enrolling in therapy, the partial response rate (> 50% decline in PSA for > 4 weeks) was 14.2%, whereas the partial response was 44% for those patients who discontinued their antiandrogen at the time of starting suramin and aminoglutethimide. The median time to progression was 3.9 months in patients failing prior antiandrogen withdrawal and 5.5 months in those patients having concomitant antiandrogen withdrawal (P = 0.36 for the overall difference). The progression-free survival estimate at 1 year for patients having prior antiandrogen withdrawal was 19.8% [95% confidence interval (CI), 11-32.9%]. For those patients who experienced antiandrogen withdrawal simultaneous with the treatment, the progression-free survival estimates at 1 and 2 years were 27.1 (95% CI, 13.2-47.6%) and 4.5% (95% CI, 0.8-21.6%). The median survival time for those patients having prior antiandrogen withdrawal was 14.2 months, whereas the median survival was 21.9 months for those having concomitant antiandrogen withdrawal (P = 0.029 for the overall difference). In conclusion, the partial response rate of 44% for those who had concomitant flutamide withdrawal with adrenal suppression was consistent with that of other reports using a similar maneuver. Although this study was not randomized and thus we should not over-interpret the results, flutamide withdrawal plus adrenal suppression appears to have greater activity than flutamide withdrawal alone. Furthermore, these data suggest that suramin adds little to the response rate observed for other adrenal suppressive agents in the presence of antiandrogen withdrawal. This interpretation is in agreement with those studies controlling for adrenal suppression and flutamide withdrawal prior to suramin administration, which noted modest activity of short duration. Given that antiandrogen withdrawal is now accepted as an active maneuver for a subset of patients progressing after maximum androgen blockade, we propose that future trials attempting to maximize response rates incorporate this maneuver whenever possible into prospectively designed regimens.

Adult↗

PubMed1997

Defective placental vasculogenesis causes embryonic lethality in VHL-deficient mice.

Inheritance of an inactivated form of the VHL tumor suppressor gene predisposes patients to develop von Hippel-Lindau disease, and somatic VHL inactivation is an early genetic event leading to the development of sporadic renal cell carcinoma. The VHL gene was disrupted by targeted homologous recombination in murine embryonic stem cells, and a mouse line containing an inactivated VHL allele was generated. While heterozygous VHL (+/-) mice appeared phenotypically normal, VHL -/- mice died in utero at 10.5 to 12.5 days of gestation (E10.5 to E12.5). Homozygous VHL -/- embryos appeared to develop normally until E9.5 to E10.5, when placental dysgenesis developed. Embryonic vasculogenesis of the placenta failed to occur in VHL -/- mice, and hemorrhagic lesions developed in the placenta. Subsequent hemorrhage in VHL -/- embryos caused necrosis and death. These results indicate that VHL expression is critical for normal extraembryonic vascular development.

Animals↗

PubMed1997

Fine-needle aspiration of metastatic clear cell carcinoma of the kidney: employment of microdissection and the polymerase chain reaction as a potential diagnostic tool.

BACKGROUND: The differential diagnosis of metastatic clear cell carcinoma is broad. To date, there are no specific immunohistochemical markers for renal cell carcinoma (RCC) in general use. Loss of heterozygosity (LOH) at 3p25.5, the von Hippel-Lindau (VHL) gene locus, is frequent in sporadic clear cell RCC. The authors compared LOH in primary and metastatic RCC through microdissection and the polymerase chain reaction (PCR) to evaluate these techniques as potential diagnostic tools. METHODS: The authors identified 14 patients with known clear cell RCC who underwent fine-needle aspiration (FNA) evaluation of presumed metastatic lesion. Direct-visualization microdissection was performed from archival histologic glass slides of the primary neoplasm and the adjacent normal kidney parenchyma. Malignant cell clusters were microdissected from archival FNA slides of metastatic lesions. The cytology slides were previously stained with either Diff-Quik or Papanicolaou stain. This was followed by a single-step DNA extraction and PCR amplification for evaluation of LOH using polymorphic markers, D3S1038 and D3S1110, flanking the VHL gene. RESULTS: Thirteen of the 14 cases contained DNA suitable for PCR in both the paraffin embedded and the FNA material. Eight of the 13 cases were heterozygous (informative) for the above markers, and 6 of these showed identical allelic loss in the primary and metastatic tumor for either one or both of the markers used. The remaining two cases did not show LOH at the VHL locus with the two polymorphic markers used. CONCLUSIONS: DNA from archival cytologic material stained with Papanicolaou stain or Diff-Quik is reliable for PCR amplification. Visually directed microdissection in combination with PCR has the potential to be a useful technique for confirmatory identification and diagnosis of metastatic clear cell RCC in cytologic material, because a specific genetic abnormality is present in the primary tumor. As characteristic genetic abnormalities are identified in various neoplasms, the use of this technique has the potential for conclusive evaluation of metastatic disease with FNA material, when used in comparison with surgical or cytologic material from the primary tumor. The utility of this combination of techniques has the potential for the molecular diagnosis of morphologically ambiguous cell populations.

Adenocarcinoma, Clear Cell↗

PubMed1997

Endolymphatic sac tumors. A source of morbid hearing loss in von Hippel-Lindau disease.

OBJECTIVES: Isolated reports suggest a possible association of endolymphatic sac tumors (ELSTs), which are extremely rare in the general population, with von Hippel-Lindau disease (VHL). To determine if hearing loss and ELSTs are a component of VHL, we examined prevalence, clinical presentation, and natural history of hearing loss and ELSTs in VHL. DESIGN: Brain magnetic resonance images (MRIs) from 374 patients screened for VHL were reviewed for evidence of ELSTs. The VHL patients with MRI evidence suggestive of ELSTs or a history of hearing loss, tinnitus, or vertigo underwent additional radiologic and audiologic evaluations. To further assess prevalence of hearing loss and ELST in VHL, the next 66 patients screened in the VHL clinic (49 with proven VHL, 17 at risk for VHL) received MRI and audiologic assessment. SETTING: Referral center. PARTICIPANTS: Study subjects comprised 374 persons screened for VHL, 66 consecutive patients with VHL or at risk for VHL, 4 patients with 6 ELSTs, and 13 previously reported patients with VHL and invasive tumors of the temporal bone. INTERVENTION: Magnetic resonance image and computed tomographic (CT) scan of the posterior fossa and audiologic assessment. MAIN OUTCOME MEASURES: Any ELST visible on MRI or CT and hearing loss compatible with ELST. RESULTS: Magnetic resonance imaging revealed evidence of 15 ELSTs in 13 (11%) of 121 patients with VHL, but in none of the 253 patients without evidence of VHL (P<.001). Clinical findings in these 13 patients included hearing loss (13), tinnitus (12), vertigo (8), and facial paresis (1). Mean age at onset of hearing loss was 22 years (range, 12-50 years). Hearing for pure tones was abnormal in all affected ears and in 6 of the 11 additional, allegedly unaffected ears. In 8 patients (62%), hearing loss was the first manifestation of VHL. Presence or absence of hearing loss was associated with duration of symptoms (P<.002) and with tumor size (P<.01). Further, 43 (65%) of the 66 patients from the VHL clinic had pure tone threshold abnormalities, abnormalities that occurred bilaterally in 23 (54%) of the 43 affected subjects; however, evidence is lacking for a definitive association with ELST (3 [6%] of 49 patients with proven VHL had ELST evident on MRI). CONCLUSIONS: Hearing loss and ELSTs are frequently associated with VHL syndrome and should be considered when screening individuals at risk for VHL and when monitoring patients with an established diagnosis of VHL. Many patients with VHL have hearing loss without radiographic evidence of an ELST. Whether it is caused by an ELST that is too small to be detected by MRI or is produced by some other etiology is still unknown. Audiologic evaluation and MRI should allow early detection and enhance management of hearing loss in these patients.

Age of Onset↗

PubMed1997

The von Hippel-Lindau tumor-suppressor gene product forms a stable complex with human CUL-2, a member of the Cdc53 family of proteins.

The inactivation of the von Hippel-Lindau (VHL) gene predisposes affected individuals to VHL syndrome and is an early genetic event associated with sporadic renal cell carcinoma and CNS hemangioblastomas. The VHL protein (pVHL) has been shown to form a stable complex with elongin B and elongin C, two factors that stabilize and activate the transcription elongation factor elongin A. Here, Hs-CUL-2, a member of the recently identified multigene family, the cullins, is shown to specifically associate with the trimeric pVHL-elongin B-C (VBC) complex in vitro and in vivo. Nearly 70% of naturally occurring cancer-predisposing mutations of VHL disrupt this interaction. The pVHL-Hs-CUL-2 association is strictly dependent on the integrity of the trimeric VBC complex. Immunofluorescence studies show Hs-CUL-2 to be a cytosolic protein that can be translocated to the nucleus by pVHL. Recently it has been shown that a yeast Hs-CUL-2 homolog, Cdc53, is part of a ubiquitin protein ligase complex that targets cell cycle proteins for degradation by the ubiquitin proteolytic pathway. In Caenorhabditis elegans, a null mutation of another Hs-cul-2 homolog, Ce-cul-1, results in hyperplasia in all tissues and is required for cell cycle exit. Hence, Hs-cul-2 may be required for VHL function and, therefore, may be a candidate human tumor-suppressor gene.

Amino Acid Sequence↗

PubMed1997

Generation and genetic characterization of immortal human prostate epithelial cell lines derived from primary cancer specimens.

Difficulty in establishing long-term human prostate epithelial cell lines has impeded efforts to understand prostate tumorigenesis and to develop alternative therapies for prostate cancer. In the current study, we describe a method that was successful in generating 14 immortal benign or malignant prostate epithelial cell cultures from primary adenocarcinomas of the prostate resected from six successive patients. Immortalization with the E6 and E7 transforming proteins of human papilloma virus serotype 16 was necessary to establish long-term cultures. Microscopic examination of fresh tumor specimens exhibited a variable mixture of benign and malignant epithelium. Thus, single-cell cloning of tumor-derived cell cultures was essential for defining tumor cell lines. Efforts to characterize these cultures using traditional criteria such as karyotype, growth in nude mice, and prostate-specific antigen expression were noninformative. However, allelic loss of heterozygosity (LOH) represents a powerful alternative method for characterizing tumor cell lines originating from primary adenocarcinomas of the prostate. Microdissected fresh tumors from four of six patients revealed LOH at multiple loci on chromosome 8p, as assessed by PCR. LOH on chromosome 8p matching the patterns found in microdissected tumors was also observed in a tumor-derived cell line and its clones, as well as in one clone from a tumor-derived cell line from a second patient. LOH was not observed in immortal lines generated from autologous benign prostatic epithelium, seminal vesicle epithelium, or fibroblasts. The multifocal nature of prostate cancer, as well as the presence of an entire spectrum of malignant transformation within individual prostate glands, necessitates this type of careful analysis of derivative cell cultures for their validation as in vitro models that accurately reflect the primary cancers from which they are derived.

Adenocarcinoma↗

PubMed1997

Cytoreductive surgery before high dose interleukin-2 based therapy in patients with metastatic renal cell carcinoma.

PURPOSE: We defined the outcome of a strategy using cytoreductive surgery before high dose interleukin-2 (IL-2) therapy in patients with metastatic renal cell carcinoma. MATERIALS AND METHODS: During an 11-year period, 195 patients underwent cytoreductive surgery as preparation for high dose IL-2 based therapy. The renal primary and locoregional metastatic disease that could be safely resected was removed. RESULTS: Because of the large size 176 of 195 renal tumors (90%) were resected through transabdominal incision and in 45 patients (23%) a second additional significant procedure was performed. Five cases (2.6%) were unresectable and 2 (1%) perioperative deaths occurred. After surgery 121 of 195 patients (62%) were eligible for treatment with high dose IL-2 based protocols. Overall response rate to IL-2 based protocols was 18%. CONCLUSIONS: Cytoreductive surgery can be performed safely in patients with metastatic renal cell carcinoma. Although the impact of cytoreductive surgery on response to immunotherapy remains undefined, this combination of primary debulking and systemic IL-2 can result in durable complete tumor regression in some patients with metastatic renal cell carcinoma.

Adolescent↗

PubMed1997

Pulmonary infarcts can mimic pulmonary metastases from renal cancer.

PURPOSE: Spontaneous regression of pulmonary metastases from renal cell carcinoma is a rare but well documented event. We present 2 recent cases that were radiographically consistent with pulmonary metastases from renal cell carcinoma but were pathologically shown to be pulmonary infarcts with no evidence of metastatic cells. Stable pulmonary infarcts can be misconstrued as metastatic disease in patients with renal cell carcinoma while resolving pulmonary infarcts may represent a subpopulation of patients with apparent spontaneous regression. Clinical implications of these findings are discussed. MATERIALS AND METHODS: Clinical and pathological data from 2 patients with large primary renal tumors, venous thrombi and lung masses were reviewed. Data from these cases, as well as pertinent urological and pathological literature, are presented. RESULTS: Although preoperative assessment was consistent with stage IV renal cell carcinoma, pathological examination of the lung masses in these patients showed no evidence of tumor cells. CONCLUSIONS: Pulmonary infarcts may mimic resolving or stable pulmonary metastasis in patients with renal cell carcinoma. Accurate clinical staging is crucial for the prognosis and treatment of renal cell carcinoma. Mistaking pulmonary infarcts for metastatic lesions can lead to inaccurate prognoses and inappropriate treatment.

Carcinoma, Renal Cell↗

PubMed1997

Loss of heterozygosity on the short arm of chromosomes 1 and 3 in sporadic pheochromocytoma and extra-adrenal paraganglioma.

Pheochromocytomas and extra-adrenal paragangliomas are tumors of the paraganglia with similar histological characteristics. We examined 12 sporadic pheochromocytomas and 5 extra-adrenal paragangliomas for loss of heterozygosity (LOH) in chromosomes 1p and 3p using a microdissection technique. Chromosomes 1p34-36, 3p21 and the von Hippel-Lindau (VHL) gene locus (3p25) were analyzed. LOH of a selected region on chromosome 1p was detected in 5 of 11 (45%) informative pheochromocytoma cases and in 0 of 5 (0%) informative extra-adrenal paraganglioma cases. LOH of the chromosome 3p25 VHL gene locus was detected in 5 of 9 (45%) informative pheochromocytoma cases and in 0 of 3 (0%) informative extra-adrenal paraganglioma cases. LOH of 3p21 was detected in 2 of 4 (50%) informative extra-adrenal paraganglioma cases. The allelic deletions in chromosomes 1p and 3p appear to be separate events. In conclusion, significant deletions were found at 1p34-36 and 3p25 in sporadic pheochromocytomas but not in extra-adrenal paragangliomas. These findings suggest (1) that multiple genetic factors may be involved in pheochromocytoma tumorigenesis, and (2) extra-adrenal paragangliomas may have a different genetic mechanism of tumorigenesis compared with pheochromocytomas.

Adolescent↗

PubMed1997

von Hippel-Lindau gene deletion detected in the stromal cell component of a cerebellar hemangioblastoma associated with von Hippel-Lindau disease.

Central nervous system hemangioblastoma is a neoplasm with characteristic and well-described histopathological features, including proliferation of vascular and stromal cells. yet, the histogenesis of the stromal cell component and its neoplastic capacity as compared with the vascular component are still controversial. Stromal cells were selectively procured from formalin-fixed, paraffin-embedded archival tissue from a von Hippel-Lindau (VHL) disease patient with a cerebellar hemangioblastoma and studied for loss of heterozygosity (LOH) of the VHL gene locus and associated microsatellite regions. The stromal cells consistently showed LOH. Analysis of mixed stromal anti vascular areas of this tumor and four other hemangioblastomas of VHL patients showed that loss of heterozygosity was partially obscured. These preliminary results suggest that the stromal component of hemangioblastomas contains genetic alterations consistent with a neoplastic nature. Additional samples of pure stromal cells need to be analyzed to establish the prevalence of VHL gene deletion in stromal cells of capillary hemangioblastoma and, hence, its pathogenetic significance.

Cerebellar Neoplasms↗

PubMed1997

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.

Adolescent↗