Biomedical subjects

Andrew Arnold

Publications and source records attributed to Andrew Arnold.

At least 19 recordsLinked to original sources

PubMed2006

Mutational analysis of the vitamin D receptor does not support its candidacy as a tumor suppressor gene in parathyroid adenomas.

CONTEXT: The vitamin D receptor gene (VDR) is a compelling candidate tumor suppressor gene for parathyroid adenomas based on existing evidence of the vitamin D system's antiproliferative actions in parathyroid and other tissues, its reported inhibition of PTH gene transcription, and the decreased expression of VDR mRNA and VDR protein observed in parathyroid adenomas. OBJECTIVE: Because demonstration of intragenic mutations is required to establish the authenticity and primary role in pathogenesis for any candidate tumor suppressor gene, we examined the VDR gene in parathyroid adenomas for the presence of such mutations and other loss-of-function abnormalities. METHODS AND RESULTS: Genomic DNA samples from 37 sporadic parathyroid adenomas and matched normal control DNA from the same individuals were subjected to direct sequencing of the entire VDR coding region and all intron-exon boundaries. No VDR coding region or junctional mutations were identified. The tumors were also analyzed for loss of heterozygosity, a frequent mechanism of tumor suppressor gene inactivation, by molecular allelotyping at three microsatellite markers located near the VDR gene, D12S85, D12S96, and D12S368, and a polymorphism within VDR itself. In all 37 cases, at least one marker was informative and no tumor-specific loss of heterozygosity was observed. CONCLUSION: We found no evidence of allelic loss within or near the VDR locus and no mutations within the splice junctions and coding regions of the VDR gene in 37 typical sporadic parathyroid adenomas. Thus, VDR is most unlikely to commonly serve as a classical tumor suppressor gene in sporadic parathyroid adenomas.

Adenoma↗

PubMed2006

Primary hyperparathyroidism with a low-normal, atypical serum parathyroid hormone as shown by discordant immunoassay curves.

CONTEXT: In patients with primary hyperparathyroidism (PHP), one expects to find a serum PTH in the high or high-normal range. The presence of a low-normal PTH in PHP can be difficult to explain. OBJECTIVE: Our objective was to investigate the cause of a low-normal serum PTH in a patient with PHP. PATIENT: A 57-yr-old asymptomatic white female from the private practice of F.W.L. presented with an 8-yr history of a rising serum calcium from 10.5-11.6 mg/dl (2.63-2.88 mmol/liter) and a low-normal serum intact PTH of 29.2 pg/ml. After localization of a parathyroid adenoma by [(18)F]fluorodesoxyglucose positron emission tomography scanning, a 120-mg parathyroid adenoma was removed with the achievement of normocalcemia for the subsequent 2 yr. METHODS: Routine pre- and postoperative serum intact PTH assays were preformed at both the Quest Diagnostics regional laboratory in Pittsburgh, Pennsylvania, and at the Quest Diagnostics Nichols Institute in California. In addition, intact, biointact, and C-terminal assays were measured in undiluted, 1:2 diluted, and 1:4 diluted sera at the Nichols Institute. PTH gene sequence analysis was performed from DNA extracted both from the parathyroid adenoma and the patient's peripheral blood leukocytes. RESULTS: Dilution, with correction for the dilution factor, of the preoperative serum produced a progressive rise in the intact, biointact, and the C-terminal assays, whereas no dilution effect was seen in postoperative serum. No intragenic mutations in the pre-pro-PTH coding region were found in either the parathyroid adenoma or matched blood DNA samples. CONCLUSIONS: The discordant preoperative immunoassay curves with dilution could not be explained by the adenoma producing a mutated PTH. Furthermore, an autoantibody against the PTH produced by the adenoma is ruled out by the prompt loss of the dilution effect in the three PTH assays within 1 wk of the adenoma's excision. A posttranslational effect on the PTH molecule within the adenoma remains a possible explanation for the discordant immunoassay curves. Our report emphasizes that one cannot always rule out PHP because of a low-normal serum intact or biointact PTH. Repeated PTH measurements after serum dilution in suspected cases of PHP with low-normal PTH levels may be a useful method for detecting atypical forms of PTH.

Female↗

PubMed2006

Review: Should patients with apparently sporadic pheochromocytomas or paragangliomas be screened for hereditary syndromes?

CONTEXT: The recent identification of germline mutations of the mitochondrial complex II genes in variants of paraganglioma/pheochromocytoma syndrome has enlarged the number of known causative genes for hereditary pheochromocytoma. A question confronting clinicians is whether they should screen patients with apparently sporadic pheochromocytomas for unsuspected germline mutations of some or all of the seven genes known to cause hereditary paraganglioma or pheochromocytoma (NF1, VHL, RET, MEN1, SDHD, SDHC, and SDHB). A positive answer was suggested by a report that placed the estimate of hereditary disease in apparently sporadic pheochromocytoma as high as 24%. EVIDENCE ACQUISITION: We applied clinically useful criteria to a review of the literature, defining cases of apparently sporadic pheochromocytoma as those without a suspicious personal or family history, with a focal, unilateral pheochromocytoma, and presenting at age less than 50 yr. EVIDENCE SYNTHESIS: We reduced the overall estimate of unsuspected hereditary pheochromocytoma patients with apparently sporadic pheochromocytoma to approximately 17%. Mutations in only three genes (VHL, SDHB, and SDHD) accounted for almost this entire minority, and unsuspected RET mutation was rare. Costs, coverage by insurance, the potential effect on insurability, and deficient information for populations outside of referral centers should be considered before recommending genetic testing in patients with apparently sporadic presentations of pheochromocytomas. CONCLUSION: We recommend genetic testing for patients with an apparently sporadic pheochromocytoma under the age of 20 yr with family history or features suggestive of hereditary pheochromocytoma or for patients with sympathetic paragangliomas. For individuals who do not meet these criteria, genetic testing is optional.

Adult↗

PubMed2006

Mutational analysis of the PTH 3'-untranslated region in parathyroid disorders.

OBJECTIVE: Sequence alterations in untranslated regions (UTRs) of genes are important contributors to human diseases, including hereditary thrombophilia, hereditary hyperferritinaemia-cataract and fragile X mental retardation syndromes. Recently, functional studies of the 3'-UTR of the PTH gene, encoding parathyroid hormone, have highlighted it as a potential target for pathogenic mutations in patients with parathyroid dysfunction. Regulation of PTH gene expression occurs in part through protein binding to a specific 26 nucleotide instability element in the 3'-UTR of PTH mRNA, in a sequence-dependent manner. Thus, the PTH 3'-UTR has emerged as an important potential contributor to parathyroid dysfunction. Therefore, we sought to rigorously examine the PTH 3'-UTR in patients with primary and secondary parathyroid disorders, including primary parathyroid hyperplasia, secondary parathyroid hyperplasia, sporadic parathyroid adenoma and familial hypoparathyroidism of unknown genetic basis. PATIENTS AND DESIGN: Twenty-one parathyroid glands from 14 patients with primary parathyroid hyperplasia, 40 sporadic parathyroid adenomas from 40 patients, 42 parathyroid glands from 29 patients with secondary parathyroid hyperplasia and peripheral blood leucocytes from 24 affected members of eight kindreds with familial hypoparathyroidism of unknown genetic basis were examined for mutations in the 3'-UTR of the PTH gene. RESULTS: No alterations from the normal sequence were detected in any of the 127 samples examined. CONCLUSIONS: Based on the absence of identifiable DNA sequence alterations in these forms of parathyroid dysfunction, it is unlikely that mutation of the PTH 3'-UTR contributes frequently to their pathogenesis.

3' Untranslated Regions↗

PubMed2006

Cyclin D1 determines mitochondrial function in vivo.

The cyclin D1 gene encodes a regulatory subunit of the holoenzyme that phosphorylates and inactivates the pRb tumor suppressor to promote nuclear DNA synthesis. cyclin D1 is overexpressed in human breast cancers and is sufficient for the development of murine mammary tumors. Herein, cyclin D1 is shown to perform a novel function, inhibiting mitochondrial function and size. Mitochondrial activity was enhanced by genetic deletion or antisense or small interfering RNA to cyclin D1. Global gene expression profiling and functional analysis of mammary epithelial cell-targeted cyclin D1 antisense transgenics demonstrated that cyclin D1 inhibits mitochondrial activity and aerobic glycolysis in vivo. Reciprocal regulation of these genes was observed in cyclin D1-induced mammary tumors. Cyclin D1 thus integrates nuclear DNA synthesis and mitochondrial function.

Animals↗

PubMed2006

Surveillance for early detection of aggressive parathyroid disease: carcinoma and atypical adenoma in familial isolated hyperparathyroidism associated with a germline HRPT2 mutation.

UNLABELLED: Familial hyperparathyroid syndromes involving mutations of HRPT2 (also CDC73), a tumor suppressor, are important to identify because the relatively high incidence of parathyroid malignancy associated with such mutations warrants a specific surveillance strategy. However, there is a dearth of reports describing experience with surveillance and early detection informed by genetic insight into this disorder. INTRODUCTION: Familial isolated hyperparathyroidism (FIHP) is a rare cause of parathyroid (PT) tumors without other neoplasms or endocrinopathies. Germline mutations in CASR, MEN1, and rarely, HRPT2 have been identified in kindreds with FIHP. HRPT2 mutations may be enriched in FIHP families with PT carcinoma, underscoring the importance of identifying causative mutations. MATERIALS AND METHODS: A 13-year-old boy, whose father had died of PT carcinoma, developed primary hyperparathyroidism. A left superior PT mass was identified by ultrasonography and removed surgically. Aggressive histological features of the boy's tumor included fibrous trabeculae, mitoses, and microscopic capsular infiltration. Two years later, under close biochemical surveillance, primary hyperparathyroidism recurred 5 months after documentation of normocalcemia and normal parathyroid status. Ultrasound and MRI identified a newly enlarged right superior PT gland but indicated no recurrent disease in the left neck. Histologic features typical of a benign adenoma were evident after surgical extirpation of the gland. RESULTS: Leukocyte DNA analysis revealed a frameshift mutation in exon 2 of HRPT2. The initial tumor manifested the expected germline HRPT2 mutation, plus a distinct somatic frameshift mutation, consistent with the Knudson "two hit" concept of biallelic inactivation of a classic tumor suppressor gene. Genetic screening of the patient's 7 asymptomatic and previously normocalcemic siblings revealed three with the same germline HRPT2 mutation. One of the siblings newly identified as mutation-positive was noted to be hypercalcemic at the time of the genetic screening. He was found to have a PT adenoma with aggressive features. Two of the five children of another mutation-positive sibling also carry the same HRPT2 mutation. CONCLUSIONS: Despite the reported rarity of HRPT2 mutations in FIHP, a personal or family history of PT carcinoma in FIHP mandates serious consideration of germline HRPT2 mutation status. This information can be used in diagnostic and management considerations, leading to early detection and removal of potentially malignant parathyroid tumors.

Adenoma↗

PubMed2005

Hypercalcemia of malignancy due to ectopic transactivation of the parathyroid hormone gene.

CONTEXT: The physiology of PTH is well described, but regulation of PTH gene expression remains enigmatic. This is, at least in part, because of a lack of suitable cell culture systems. OBJECTIVE, DESIGN, SETTING, PATIENTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: We report a case of severe hyperparathyroidism resulting from the ectopic production of PTH by a pancreatic malignancy. Cells from the primary tumor (PEPP1 cells) were established in culture to examine the etiology of ectopic PTH gene expression in this patient. RESULTS AND CONCLUSIONS: We failed to find amplification or rearrangement of the PTH gene but documented hypomethylation of the PTH promoter in tumor tissue. We found that PEPP1 cells support expression of a reporter gene containing regulatory sequences from the human PTH gene promoter. Therefore, this is the first report documenting ectopic PTH production by a tumor as the result of transactivation of the PTH gene. PEPP1 cells may be useful for future studies aimed at elucidating the details of PTH gene regulation.

Aged↗

PubMed2005

Cyclin D1 in breast cancer pathogenesis.

Taking a perspective on available evidence that emphasizes relevance to human disease, cyclin D1 is solidly established as an oncogene with an important pathogenetic role in breast cancer and other human tumors. However, the precise cellular mechanisms through which aberrant cyclin D1 expression drives human neoplasia are less well established. Indeed, emerging evidence suggests that cyclin D1 might act, predominantly or at least in part, through pathways that do not involve its widely accepted function as a cell cycle regulator. Although therapeutic exploitation of the role of cyclin D1 as a molecular driver of breast cancer carries great promise, it is also suggested that direct targeting of the cyclin D1 gene or gene products may prove more successful than approaches that rely on arguably incomplete knowledge of the oncogenic mechanisms of cyclin D1.

Breast Neoplasms↗

PubMed2005

HRPT2 mutational analysis of typical sporadic parathyroid adenomas.

CONTEXT: Mutations of HRPT2 are frequent in sporadic parathyroid carcinomas and central to their pathogenesis. However, the potential diagnostic utility of HRPT2 mutation status to distinguish between parathyroid carcinoma and adenoma hinges on the frequency of HRPT2 mutations in benign adenomas. Even a low rate of HRPT2 mutation in adenomas would greatly alter diagnostic specificity, because adenomas are far more prevalent than carcinomas. The issue remains open because of the limited number of typical adenomas, not subjected to additional selection criteria, examined in previous studies. OBJECTIVE/DESIGN/PATIENTS: To determine the frequency of HRPT2 somatic mutations in a substantial series of typical, sporadic parathyroid adenomas, we directly sequenced coding and flanking splice junctional regions of all HRPT2 exons in solitary adenomas from 60 patients. RESULTS/CONCLUSIONS: No intragenic HRPT2 mutations were detected, strengthening the degree of specificity of HRPT2 mutation as a feature of sporadic parathyroid carcinoma as opposed to sporadic adenomas. Our observations encourage additional study of the diagnostic potential of HRPT2 in parathyroid neoplasia and support the view that HRPT2 inactivation is not an important participant in the pathogenesis of typical parathyroid adenomas.

Adenoma↗

PubMed2005

Independent clonal origins of distinct tumor foci in multifocal papillary thyroid carcinoma.

BACKGROUND: Papillary thyroid carcinoma is frequently multifocal. We investigated whether noncontiguous tumor foci arise from intraglandular metastases from a single primary tumor or originate as unrelated clones derived from independent precursors. METHODS: Using a polymerase-chain-reaction assay involving the human androgen receptor gene (HUMARA), we analyzed the patterns of X-chromosome inactivation of multiple distinct foci of well-differentiated multifocal papillary thyroid cancer from 17 women. RESULTS: Multiple thyroid tumor foci from 10 of 17 patients yielded DNA of adequate quality and were heterozygous for the HUMARA polymorphism and hence suitable for analysis. A single X chromosome was inactivated in each focus, consistent with its monoclonality. When the specific monoclonal configurations of each patient's discrete tumor foci were compared, discordant patterns indicative of independent origins were observed among the tumors from five patients; results in the remaining five were consistent with either a shared or independent clonal origin. CONCLUSIONS: Individual tumor foci in patients with multifocal papillary thyroid cancer often arise as independent tumors.

Carcinoma, Papillary↗

PubMed2005

Abnormal parathyroid cell proliferation precedes biochemical abnormalities in a mouse model of primary hyperparathyroidism.

The properties of neoplastic proliferation and hormonal dysregulation are tightly linked in primary hyperparathyroidism (HPT). However, whether abnormal parathyroid proliferation is the cause or result of a shift in calcium-sensitive parathyroid hormonal regulation has been controversial. We addressed this issue by analyzing the temporal sequence of these fundamental abnormalities in a mouse model of primary HPT. These transgenic mice (PTH-D1) harbor a transgene that targets overexpression of the cyclin D1 oncogene to parathyroid cells, resulting in parathyroid hypercellularity with a phenotype of chronic biochemical HPT and, notably, an abnormal in vivo PTH-calcium set point. We examined parathyroid cell proliferation and biochemical alterations in PTH-D1 and control wild-type mice from ages 1-14 months. Strikingly, abnormal parathyroid proliferation regularly preceded dysregulation of the calcium-PTH axis, supporting the concept that disturbed parathyroid proliferation is the crucial primary initiator leading to the development of the biochemical phenotype of HPT. Furthermore, we observed that decreased expression of the calcium-sensing receptor in the parathyroid glands occurs several months before development of biochemical HPT, suggesting that decreased calcium-sensing receptor may not be sufficient to cause PTH dysregulation in this animal model of primary HPT.

Animals↗

PubMed2005

Randomized phase III study of matrix metalloproteinase inhibitor BMS-275291 in combination with paclitaxel and carboplatin in advanced non-small-cell lung cancer: National Cancer Institute of Canada-Clinical Trials Group Study BR.18.

PURPOSE: To determine whether BMS-275291, a broad-spectrum matrix metalloproteinase inhibitor (MMPI), added to systemic chemotherapy improved survival in advanced non-small-cell lung cancer (NSCLC). In early phase studies, BMS- 275291 was not associated with dose-limiting joint toxicity seen with other MMPIs. PATIENTS AND METHODS: Chemotherapy-naive patients with stage IIIB/IV NSCLC, performance status (PS) 0 to 2, and adequate organ function were eligible. All patients received paclitaxel 200 mg/m2 plus carboplatin (area under the curve, 6 mg/mL-min) intravenously every 21 days for up to 8 cycles, and were randomly assigned to receive BMS-275291, 1,200 mg orally daily, or placebo until disease progression. The primary study end point was survival (OS); secondary end points included progression-free survival (PFS), response rates (RR), toxicity, and quality of life. RESULTS: From 2000 to 2002, 774 patients were randomly assigned. Pretreatment characteristics were well balanced between arms: median age, 61 years; male sex, 73%; stage IV, 79%; PS 0 to 1, 88%. Interim safety analysis revealed no survival advantage and increased toxicity in the experimental arm, and study treatment was stopped. Median OS, PFS and RR in the final analysis in the BMS-275291 arm were 8.6 months, 4.9 months, and 25.8% respectively, and in the control arm 9.2 months, 5.3 months, 33.7%. Toxicity was significantly higher in the BMS-275291 arm, including flu-like symptoms, rash, hypersensitivity reactions (8.6% v 2.4%), and febrile neutropenia (9.7% v 5.5%). CONCLUSION: BMS-275291 added to chemotherapy increases toxicity and does not improve survival in advanced NSCLC.

Administration, Oral↗

PubMed2005

Effects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial.

CONTEXT: Experimental and epidemiological data suggest that vitamin E supplementation may prevent cancer and cardiovascular events. Clinical trials have generally failed to confirm benefits, possibly due to their relatively short duration. OBJECTIVE: To evaluate whether long-term supplementation with vitamin E decreases the risk of cancer, cancer death, and major cardiovascular events. DESIGN, SETTING, AND PATIENTS: A randomized, double-blind, placebo-controlled international trial (the initial Heart Outcomes Prevention Evaluation [HOPE] trial conducted between December 21, 1993, and April 15, 1999) of patients at least 55 years old with vascular disease or diabetes mellitus was extended (HOPE-The Ongoing Outcomes [HOPE-TOO]) between April 16, 1999, and May 26, 2003. Of the initial 267 HOPE centers that had enrolled 9541 patients, 174 centers participated in the HOPE-TOO trial. Of 7030 patients enrolled at these centers, 916 were deceased at the beginning of the extension, 1382 refused participation, 3994 continued to take the study intervention, and 738 agreed to passive follow-up. Median duration of follow-up was 7.0 years. INTERVENTION: Daily dose of natural source vitamin E (400 IU) or matching placebo. MAIN OUTCOME MEASURES: Primary outcomes included cancer incidence, cancer deaths, and major cardiovascular events (myocardial infarction, stroke, and cardiovascular death). Secondary outcomes included heart failure, unstable angina, and revascularizations. RESULTS: Among all HOPE patients, there were no significant differences in the primary analysis: for cancer incidence, there were 552 patients (11.6%) in the vitamin E group vs 586 (12.3%) in the placebo group (relative risk [RR], 0.94; 95% confidence interval [CI], 0.84-1.06; P = .30); for cancer deaths, 156 (3.3%) vs 178 (3.7%), respectively (RR, 0.88; 95% CI, 0.71-1.09; P = .24); and for major cardiovascular events, 1022 (21.5%) vs 985 (20.6%), respectively (RR, 1.04; 95% CI, 0.96-1.14; P = .34). Patients in the vitamin E group had a higher risk of heart failure (RR, 1.13; 95% CI, 1.01-1.26; P = .03) and hospitalization for heart failure (RR, 1.21; 95% CI, 1.00-1.47; P = .045). Similarly, among patients enrolled at the centers participating in the HOPE-TOO trial, there were no differences in cancer incidence, cancer deaths, and major cardiovascular events, but higher rates of heart failure and hospitalizations for heart failure. CONCLUSION: In patients with vascular disease or diabetes mellitus, long-term vitamin E supplementation does not prevent cancer or major cardiovascular events and may increase the risk for heart failure.

Aged↗

PubMed2005

Mutational analysis of PPARG as a candidate tumour suppressor gene in enteropancreatic endocrine tumours.

OBJECTIVES: Loss of heterozygosity (LOH) or deletion of chromosome 3p is a frequent finding in enteropancreatic endocrine tumours (EPETs), suggesting the pathogenetic involvement of one or more tumour suppressor genes on 3p. PPARG, the gene encoding the gamma isoform of the peroxisome proliferator-activated receptor (PPARgamma), is highly expressed in normal human pancreatic islet cells, is located at 3p25, and has been reported to sustain loss-of-function mutations in human colorectal carcinomas. Additionally, the development of islet cell hyperplasia in an islet cell-specific pparg knockout mouse has further emphasized the attractiveness of PPARG as a candidate gene important in the pathogenesis of EPETs. Therefore, we sought to examine PPARG for intragenic inactivating mutations, the evidence needed to rigorously establish it as a tumour suppressor in EPETs. PATIENTS AND DESIGN: Twenty-three EPETs from 20 patients were examined for coding region mutations in PPARG and for LOH on 3p at microsatellite markers flanking PPARG. RESULTS: LOH on 3p was detected in tumours from six patients (30%), but no intragenic mutations were detected in PPARG, whether or not LOH was present. CONCLUSION: These findings strongly suggest that PPARG does not commonly function as a classical tumour suppressor gene in the pathogenesis of EPETs.

DNA Mutational Analysis↗

PubMed2005

Relationship between parathyroid calcium-sensing receptor expression and potency of the calcimimetic, cinacalcet, in suppressing parathyroid hormone secretion in an in vivo murine model of primary hyperparathyroidism.

Cinacalcet HCl, an allosteric modulator of the calcium-sensing receptor (CaR), has recently been approved for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease on dialysis, due to its suppressive effect on parathyroid hormone (PTH) secretion. Although cinacalcet's effects in patients with primary and secondary hyperparathyroidism have been reported, the crucial relationship between the effect of calcimimetics and CaR expression on the parathyroid glands requires better understanding. To investigate its suppressive effect on PTH secretion in primary hyperparathyroidism, in which hypercalcemia may already have stimulated considerable CaR activity, we investigated the effect of cinacalcet HCl on PTH-cyclin D1 transgenic mice (PC2 mice), a model of primary hyperparathyroidism with hypo-expression of CaR on their parathyroid glands. A single administration of 30 mg/kg body weight (BW) of cinacalcet HCl significantly suppressed serum calcium (Ca) levels 2 h after administration in 65- to 85-week-old PC2 mice with chronic biochemical hyperparathyroidism. The percentage reduction in serum PTH was significantly correlated with CaR hypo-expression in the parathyroid glands. In older PC2 mice (93-99 weeks old) with advanced hyperparathyroidism, serum Ca and PTH levels were not suppressed by 30 mg cinacalcet HCl/kg. However, serum Ca and PTH levels were significantly suppressed by 100 mg/kg of cinacalcet HCl, suggesting that higher doses of this compound could overcome severe hyperparathyroidism. To conclude, cinacalcet HCl demonstrated potency in a murine model of primary hyperparathyroidism in spite of any presumed endogenous CaR activation by hypercalcemia and hypo-expression of CaR in the parathyroid glands.

Aging↗

PubMed2004

Safety of treatment of metastatic breast cancer with trastuzumab beyond disease progression.

PURPOSE: In a pivotal phase III trial, the addition of trastuzumab to chemotherapy significantly improved response rate, time to disease progression, and overall survival in women with HER2 overexpressing metastatic breast cancer. We conducted an extension study to this trial to obtain additional safety information and to provide trastuzumab following disease progression. PATIENTS AND METHODS: A total of 247 patients with documented disease progression received weekly intravenous trastuzumab in the extension study. Concurrent therapies were administered at the discretion of the treating physician. Patient groups were based on initial study treatment: chemotherapy alone (group 1, n=154) or chemotherapy plus trastuzumab (group 2, n=93). RESULTS: Sixty-eight percent of group 1 and 76% of group 2 received chemotherapy plus trastuzumab in the extension trial; the remainder received trastuzumab alone or combined with palliative radiotherapy or hormonal therapy. Seventy-six percent of group 1 and 55% of group 2 experienced at least one adverse event, similar to effects observed in the pivotal trial. Symptomatic or asymptomatic cardiac dysfunction occurred in 9% of group 1 and 2% of group 2 patients. Overall objective response rates were 14% in group 1 and 11% in group 2; median durations of response exceeded 6 months in both groups. CONCLUSION: Our results suggest that prolonged use of trastuzumab therapy is safe and well tolerated. Longer durations of therapy did not appear to increase the risk of cardiac dysfunction. Patients progressing on trastuzumab-containing therapy demonstrate some response to a second trastuzumab-containing regimen. The independent contribution of trastuzumab in this setting merits further study.

Antibodies, Monoclonal↗

PubMed2004

Randomized phase II feasibility study of combining the matrix metalloproteinase inhibitor BMS-275291 with paclitaxel plus carboplatin in advanced non-small cell lung cancer.

BACKGROUND: This randomized, double-blind, placebo-controlled study was designed to assess whether the addition of the matrix metalloproteinase (MMP) inhibitor BMS-275291 to combined paclitaxel and carboplatin chemotherapy had an adverse impact on expected tumor response or had significant toxicity, especially arthrotoxicity, in patients with advanced non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Seventy-five chemotherapy-naive patients with stage IIIB-IV NSCLC were randomly assigned to BMS-275291 or placebo. All patients received paclitaxel 200mg/m(2) as a continuous 3-hour infusion followed by carboplatin calculated using the Calvert formula for a target AUC of 6 mg / (ml min), every 21 days for a maximum of eight cycles. BMS-275291 or placebo was administered on an outpatient basis at a daily oral dosage of 1200 mg. RESULTS: All 75 patients were evaluable for toxicity and 65 (86.7%) for response. Drug-related arthrotoxicity > or =grade 2 occurred in 12 patients (31.6%) in the BMS-275291 group (lower limit of one-sided 95% CI: 19.3) and in 11 patients (29.7%) in the placebo treatment arm. The incidence of rash was higher in patients receiving BMS-275291 (28.9% versus 18.9%). An objective response rate of 21.9% was observed in the BMS-275291 treatment arm and 36.4% in the placebo arm. CONCLUSION: BMS-275291 plus paclitaxel/carboplatin was well tolerated and active in advanced non-small cell lung cancer. Treatment with BMS-275291 was not limited by drug-related arthrotoxicity and tumor response was as expected. As planned, patient accrual continued to further investigate the effect of BMS-275291 on overall and progression-free survival in a phase III setting.

Administration, Oral↗

PubMed2003

Parathyroid gland-specific deletion of the mouse Men1 gene results in parathyroid neoplasia and hypercalcemic hyperparathyroidism.

The inactivation of the MEN1 tumor suppressor gene in patients leads to a constellation of changes in endocrine tissues, including parathyroid neoplasia, pituitary adenomas, pancreatic neuroendocrine tumors, and carcinoids. To study the pathophysiological consequences of the deletion of the MEN1 gene, we set out to create a mouse model of hyperparathyroidism resulting from the deletion of the Men1 gene in parathyroid tissue. We introduced a Men1 gene flanked by loxP sites into the mouse germ line and then used a parathyroid cell-specific promoter to drive the expression of Cre recombinase, resulting in the deletion of the Men1 gene. Here, we show that loss of Men1 gene function in the parathyroid glands of mice results in histological changes consistent with parathyroid neoplasia as well as systemic hypercalcemia. This model provides a means for dissecting the molecular basis of this familial cancer syndrome and may allow for the development of new strategies to treat related forms of hypercalcemia.

Animals↗