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PubMed1985

Frequency of molecular alterations affecting ras protooncogenes in human urinary tract tumors.

Members of the ras gene family are activated as oncogenes in many different human cancers. To systematically determine the frequency at which such genes might be involved in the neoplastic process affecting a specific target tissue, urothelial cells, we surveyed a large series of urinary tract tumors for ras oncogenes by DNA transfection and by molecular genetic analysis. Harvey (Ha)-ras oncogenes were detected in 2 of 38 tumors by transfection, molecularly cloned in biologically active form, and shown to contain single base changes at codon 61 leading to substitutions of arginine and leucine, respectively, for glutamine at this position. One additional Ha-ras oncogene was identified in a bladder carcinoma by restriction polymorphisms at codon 12. In one of 21 tumors, we observed a 40-fold amplification of the Kirsten (Ki)-ras gene. No amplification of other ras genes was detected in any of the tumors analyzed. Our findings strengthen the conclusion that codons 12 and 61 are the major "hot spots" of ras oncogene activation and suggest that quantitative alterations in expression due to gene amplification may provide an alternative mechanism for ras gene activation in primary human tumors.

Base Sequence↗
PubMed1998

Cytologically normal cells from neoplastic cervical samples display extensive structural abnormalities on IR spectroscopy: implications for tumor biology.

Fourier-transform IR (FT-IR) spectra of pelleted exfoliated cervical cells from patients with cervical cancer or dysplasia differ from those from normal women. To study the origin of these spectral changes, we obtained the FT-IR spectra of individual cervical cells from normal, dysplastic, and malignant cervical samples. Ninety five percent of normal superficial and intermediate cells displayed two distinct spectral patterns designated A and B, and 5% displayed an intermediate pattern, suggesting extensive structural heterogeneity among these cells. Parabasal and endocervical cells showed pattern B spectra. The spectra of malignant, dysplastic, and other abnormal cells also were characterized. Analysis of FT-IR spectra of over 2, 000 individual cells from 10 normal females, 7 females with dysplasia, and 5 females with squamous cell carcinoma revealed that the spectra of normal-appearing intermediate and superficial cells of the cervix from women with either dysplasia or cancer differed from those of normal women. Chemometric and classical spectroscopic analysis showed a continuum of changes paralleling the transition from normalcy to malignancy. These findings suggest that (i) the structural changes underlying the spectroscopic changes are involved in or are a product of cervical carcinogenesis and (ii) the neoplastic process may be more extensive than currently recognized with morphological criteria. This approach may be useful for the structural study of neoplasia and also may be of help in the diagnosis or classification of cervical disorders.

Adult↗
PubMed2000

Tumorigenesis in the multiple intestinal neoplasia mouse: redundancy of negative regulators and specificity of modifiers.

The interaction between mutations in the tumor-suppressor genes Apc and p53 was studied in congenic mouse strains to minimize the influence of polymorphic modifiers. The multiplicity and invasiveness of intestinal adenomas of Apc(Min/+) (Min) mice was enhanced by deficiency for p53. In addition, the occurrence of desmoid fibromas was strongly enhanced by p53 deficiency. The genetic modifier Mom1 and the pharmacological agents piroxicam and difluoromethylornithine each reduced intestinal adenoma multiplicity in the absence of p53 function. Mom1 showed no influence on the development of desmoid fibromas, whereas the combination of piroxicam and difluoromethylornithine exerted a moderate effect. The ensemble of tumor suppressors and modifiers of a neoplastic process can be usefully analyzed in respect to tissue specificity and synergy.

Adenoma↗
PubMed1996

Oncogenic RET receptors display different autophosphorylation sites and substrate binding specificities.

The c-ret proto-oncogene encodes a receptor tyrosine kinase which plays an important role in neural crest as well as kidney development. Genetic studies have demonstrated that germ line mutations in the ret oncogene are the direct cause of multiple endocrine neoplasia (MEN) 2A and 2B, familial medullary thyroid carcinoma (FMTC), and Hirschsprung's disease. However, despite the large body of genetic and biological evidence suggesting the importance of RET in development and neoplastic processes, the signal transduction mechanisms of RET remain unknown. To begin to understand the molecular mechanisms of the disease states caused by mutations in RET, the patterns of autophosphorylation of the wild-type RET and the MEN mutants were studied using site-directed mutagenesis and phosphopeptide mapping. Among the 6 autophosphorylation sites found in the wild-type RET receptor, the MEN2B mutant lacked phosphorylation at Tyr-1096, leading to decreased Grb2 binding, while simultaneously creating a new phosphorylation site. These changes in autophosphorylation suggest that the MEN2B mutation may result in the more aggressive MEN2B phenotype by altering the receptor's signaling capabilities.

Amino Acid Sequence↗
PubMed2002

Combinatorial interactions of p53, activating protein-2, and YB-1 with a single enhancer element regulate gelatinase A expression in neoplastic cells.

Gelatinase A, also denoted matrix metalloproteinase 2, plays multiple critical roles in the neoplastic process, including facilitation of neoangiogenesis and formation of distal metastases. The transcriptional regulation of the gelatinase A gene is under the control of strong, evolutionarily conserved cis-acting enhancer elements, designated the r2 (human) or RE-1 (rat), that harbor contiguous binding motifs for the transcription factors activating protein-2 (AP2), p53, and YB-1. Using recombinant transcription factors, complex patterns of RE-1 binding were observed by electrophoretic mobility shift assay. Increased complex formation was detected with the AP2/YB-1 and AP2/p53 combinations, while YB-1 competed with p53 for binding. The combination of AP2, p53, and YB-1 yielded novel ternary complexes, particularly when binding to single-stranded RE-1 probes. Transient transfection of hepatocellular carcinoma cell lines with a series of gelatinase A luciferase reporter constructs were in accordance with the binding patterns determined by electrophoretic mobility shift assay. Combined AP2 and p53 increased gelatinase A luciferase reporter activity significantly, and the inclusion of YB-1 yielded further increase in both reporter activity and secreted levels of gelatinase A protein. YB-1 and p53 expression are increased following multiple genotoxic stresses, including irradiation, and the synergistic interactions of these induced transcription factors with the widely expressed AP2 protein provide a probable pathophysiologic mechanism for the enhanced tumor cell synthesis of gelatinase A induced by radiation.

Animals↗
PubMed2002

Astroglial c-Myc overexpression predisposes mice to primary malignant gliomas.

Malignant astrocytomas are common human primary brain tumors that result from neoplastic transformation of astroglia or their progenitors. Here we show that deregulation of the c-Myc pathway in developing astroglia predisposes mice to malignant astrocytomas within 2-3 weeks of age. The genetically engineered murine (GEM) gliomas harbor a molecular signature resembling that of human primary glioblastoma multiforme, including up-regulation of epidermal growth factor receptor and Mdm2. The GEM gliomas seem to originate in an abnormal population of glial fibrillary acidic protein-expressing cells in the ventricular zone and, analogous to human glioblastomas, exhibit molecular and morphological heterogeneity. Levels of connexin 43 in the majority of the tumors are unaltered from normal tissue, indicating that GEM tumors have retained the capacity to establish syncytial networks. In line with this, individual glioma foci are composed of a mixture of actively proliferating cells expressing c-Myc and proliferating cell nuclear antigen and less dividing bystander cells that express glial fibrillary acidic protein and the broad complex tramtrack bric-a-brac/poxvirus and zinc finger domain protein HOF. A subset of the transgenic mice harbored, in addition to brain tumors, vestigial cerebellums in which granule cell migration and radial Bergman glial cell differentiation were disturbed. These observations argue for a window of vulnerability during astrocyte development where c-Myc overexpression is sufficient to trigger the neoplastic process, presumably by inducing the sustained growth of early astroglial cells. This is in contrast to most other transgenic studies in which c-Myc overexpression requires co-operating transgenes for rapid tumor induction.

Animals↗
PubMed2004

Ruptured ectopic pregnancy presenting as an irreducible inguinal hernia.

An inguinal hernia that suddenly becomes irreducible may be secondary to a variety of other underlying conditions which can occasionally mislead the attending surgeon. Benign, inflammatory or neoplastic processes, as well as surgical emergencies such as intraperitoneal or retroperitoneal haemorrhage, have all been previously reported to mimic an inguinal hernia that suddenly becomes irreducible with or without clinical features of strangulation. We add an additional interesting presentation to this list in the form of a ruptured ectopic pregnancy, which is the first such case reported in the literature. A swelling in the groin may be much more complicated than it seems on superficial consideration and good clinical acumen is constantly required in managing such cases if a satisfactory outcome without any morbidity is to be expected.

Adult↗
PubMed2005

Submandibular gland myoepithelioma.

Benign myoepithelioma is a very rare form of salivary gland tumor, composed entirely of myoepithelial cells. It accounts for approximately 1% of all salivary gland tumors and is most frequently located in the parotid gland and in the minor salivary glands of the hard palate. We describe herein the ninth reported case of myoepithelioma of the submandibular gland. Benign myoepithelioma must be differentiated from several benign and malignant epithelial and mesenchymal tumors. Immunohistochemical staining can help differentiate between these conditions, but histopathology remains the gold standard for diagnosing this neoplastic process.

Diagnosis, Differential↗
PubMed1994

HLA-DR antigen expression in colonic adenomas and adenocarcinomas.

Previous studies have shown that malignant transformation is sometimes associated with the aberrant expression of HLA class II antigens. The functional significance of such aberrant expression is not known. Since HLA-DR antigen is expressed in normal colonic mucosa, it would be interesting to see if malignant transformation could result in the aberrant suppression of this antigen. Sixteen colonic adenocarcinomas, 29 colonic adenomatous polyps and 23 samples of normal colonic mucosa, including 9 cases of colonic mucosa adjacent to carcinoma, were stained immunohistochemically for HLA-DR antigen. The intensity and distribution of the antigen staining in the cytoplasm and luminal surface of the epithelial elements were analysed semiquantitatively. The lymphoplasmacytic infiltrate in the lamina propria was also evaluated. Cytoplasmic HLA-DR antigen expression was found to be significantly diminished in moderately and poorly differentiated adenocarcinomas but not in adenomas or well-differentiated adenocarcinomas. This suggests that the change in HLA-DR expression is not intrinsic to the neoplastic process but may merely be due to the fact that malignant cells, as they become less differentiated, tend to show alterations in their antigenic phenotype.

Adenocarcinoma↗
PubMed1983

Bladder cancer. Management of an increasingly common tumor.

The incidence of bladder cancer is slowly rising, which may be due in part to the increasing use of chemicals in every phase of our modern society. Improvements in detection will, it is hoped, allow earlier diagnosis, at a stage when it is highly likely that the entire tumor can be removed. Intravesical chemotherapy reduces the number and frequency of subsequent tumors and may be able to control the neoplastic process sufficiently to prevent progression and the need for cystectomy and/or radiation therapy. Unfortunately, advances in management of superficial tumors have not been matched for invasive tumors. Despite improvements in preoperative and postoperative care, introduction of the linear accelerator, and use of chemotherapy, about 50% of patients with stage B, C, or D bladder cancer die of the disease. Most patients with invasive tumors do not come to the attention of a physician until the tumor has progressed to this stage. Thus, a major task is to identify those harboring bladder cancer earlier, when the disease can be successfully managed.

Endoscopy↗
PubMed2006

Impaired glucose metabolism in colorectal cancer.

OBJECTIVE: Some studies have found that people with type 2 diabetes mellitus are at increased risk of neoplasms, especially colorectal cancer (CRC). In other studies it is also suggested that there is a higher incidence of diabetes mellitus in patients with CRC. The aims of this study were to assess whether the incidence of type 2 diabetes mellitus and impaired glucose tolerance (IGT) are higher in subjects with CRC and to determine the difference between diabetic subjects and healthy controls regarding glucose metabolism (glycaemia, insulinaemia, serum levels of C-peptide) as well as insulin resistance and sensitivity. MATERIAL AND METHODS: The study included a total of 80 subjects: 40 enrolled patients (20 M, 20 F) with newly diagnosed sporadic colorectal cancer and 40 subjects with endoscopically excluded CRC or adenomas serving as controls. Subjects were matched for gender, age and body mass index (BMI) (age +/- 5 years BMI +/- 1 kg/m2). A 75-g oral glucose tolerance test was performed after an overnight fast. Samples for glycaemia, serum levels of C-peptide and insulin were taken at 0, 30, 60, 90, 120 and 150 min of the study. HOMA-IR, EIR, EIR/HOMA-IR indexes were calculated. RESULTS: There was a significantly higher incidence of impaired glucose metabolism (IGM-diabetes mellitus or IGT) in CRC subjects. No differences were found in levels of glucose, insulin or C-peptide. Insulinaemia and C-peptide curves showed a shift typical of diabetes, in the form of a delayed insulin release peak. The HOMA-IR, EIR as well as the EIR/HOMA-IR indexes showed no differences between groups. CONCLUSIONS: A significantly higher incidence of IGM appears to occur in CRC patients than in the healthy population. This phenomenon is not dependent on age and body-weight, which may suggest that it is cancer that predisposes to diabetes rather than the other way round. The neoplastic process in the colon is not associated with hyperinsulinaemia or insulin resistance, but in CRC patients, pancreatic B-cell dysfunction typical of the early stages of diabetes is seen.

Adult↗
PubMed1987

Interstitial radiobrachytherapy of malignant cerebral neoplasms: rationale, methodology, prospects.

The local use of radionuclides in the management of neoplastic processes was initially considered over 80 yr ago and has enjoyed increasing enthusiasm in the treatment of somatic and central nervous system tumours during the past 30 yr. The marriage of complex neuroimaging techniques and modern stereotactic devices has markedly enhanced the technical precision of interstitial radiobrachytherapy of malignant cerebral neoplasms. In applying these techniques, it is imperative to achieve an optimal placement of radionuclide sources in order to develop a geometrically homogenous, controlled distribution of radiation. Critical considerations include determination of tumour volume and contour, and development of a homogenous dose rate (dependent upon multiple sources at varying intensity) that will not only effect tumour cell kill but do this without excessive production of radionecrosis which necessitates craniotomy because of mass. Using the Brown-Roberts-Wells (BRW) stereotactic guidance system and an image-defined, volumetrically determined target, implants of multiple iridium 192(192Ir) sources were used to establish appropriate isodose envelopes. A methodology for achieving the described objectives is detailed as it applies to a variety of malignant intracerebral neoplasms (glioblastoma multiforme, malignant astrocytoma, malignant mixed glioma, primary cerebral lymphoma, metastatic carcinoma and malignant pineal region tumours). Technical realization of precision implantation relying upon imaging data may be acheived with this method with satisfactory responses that are dependent upon histological tumour type and the morphology of the tumour distribution as related to the image. Early and late complications related to the surgical technique and radionuclide applications were less than 5%. Although encouraging, these techniques require further definition and greater data accrual before uniform application outside major medical centres can be justified. It is anticipated that improvement in results with intrinsic gliomas and other invasive neoplasms will be realized with further definition of tumour boundaries by tract biopsy techniques and concurrent utilization of hyperthermia and brain protective methods.

Brachytherapy↗
PubMed1994

Folate and cancer: a review of the literature.

Folate, a water-soluble vitamin, part of the vitamin B complex, plays an important role in methylation reactions and DNA/RNA synthesis. This review examines the experimental and epidemiological evidence for the association between folate status and risk of cancer. Data have accumulated indicating that low folate status may promote carcinogenesis. Low folate levels are associated with cytogenetic abnormalities in vivo and in vitro. Findings from animal studies are conflicting and suggest that the effect of folate on neoplasia depends on factors such as the animal and tumor model, the type, timing, dose, and length of application of carcinogen, the stage of carcinogenesis, and the level and form of folate administered. Epidemiological studies examined the association between folate and cancer of the cervix, colorectum, lung, esophagus, and brain and suggest that low folate status may play an important role early in the neoplastic process. The potential for inhibition of precursor lesions in the cervix and colorectum, namely, cervical intraepithelial neoplasia and adenomatous polyps, respectively, is of particular interest. Additional research designed to clarify the role of folate in carcinogenesis is warranted.

Animals↗
PubMed1998

Dietary fiber differentially alters cellular fatty acid-binding protein expression in exfoliated colonocytes during tumor development.

We investigated the utility of noninvasive technology utilizing feces containing exfoliated colonocytes to determine whether changes in fecal fatty acid-binding proteins have predictive value in monitoring the neoplastic process. Ninety male Sprague-Dawley rats were randomly divided into four groups in a 2 x 2 factorial design, with two dietary fiber sources (wheat bran or oat bran) and two treatment groups (injection with a carcinogen, azoxymethane, or saline). Fresh fecal samples were collected at Week 16 postinjection, and tumor frequency was determined at Week 36 of the study. Semiquantitative "mimic" reverse transcriptase polymerase chain reaction was used to quantitate the expression of liver fatty acid-binding protein (L-FABP), intestinal fatty acid-binding protein (i-FABP), and acyl CoA-binding protein (ACBP) mRNA in fecal samples to establish their prognostic value. Rats fed wheat bran diets had a lower incidence of tumors (p < 0.05). There was no effect of carcinogen injection or tumor incidence on the expression of L-FABP, i-FABP, or ACBP mRNA, L-FABP and i-FABP mRNA expression were significantly higher (p < 0.05) in feces from animals fed a wheat bran diet than in feces from animals fed an oat bran diet. In contrast, the expression of ACBP mRNA was significantly lower (p < 0.05) in animals fed a wheat bran diet than in animals fed an oat bran diet. Wheat bran also increased (p < 0.05) the total excretion of L-FABP, i-FABP, and ACBP over a 48-hour period. These data suggest that exfoliated colonocyte fatty acid-binding protein mRNA status may provide insight into the mechanisms by which diet influences colonic physiology.

Animals↗
PubMed1987

Enzootic nasal tumour of sheep.

This is the first report of Enzootic Nasal Tumours (ENT) of sheep in Israel. The report includes a detailed clinical, pathological and histopathological description of the syndrome. All 7 affected sheep suffered clinically from serous to muco-purulent nasal discharge and respiratory distress due to obstruction of the upper airway by a neoplastic process. Three of the tumours were histopathologically identified as tubular adenomas, 3 were mucoid adenomas and one was a papillary adenoma. The tumours caused destruction of the turbinate bones and nasal septum.

Adenoma↗
PubMedDate not supplied

Pituitary corticotroph adenoma containing many apoptotic cells: a histologic, immunohistochemical, ultrastructural and molecular study.

Apoptosis regulates cell turnover in normal tissues and occurs during the neoplastic process. Owing to difficulties in recognizing apoptotic cells by histology alone, several complementary approaches have been introduced, which disclosed the presence of cells with typical nuclear and cytoplasmic changes characteristic of apoptosis. Electron microscopy remains the most conclusive method to reveal the structural changes. Identification of caspase cleaved keratin 18 intermediate filament rearrangements can contribute to the identification of early apoptotic changes. The authors present here an unusual case of a pituitary corticotroph adenoma removed surgically from a young woman with Cushing disease. The tumor contained many apoptotic cells identified by histology. In addition, the apoptotic events were investigated using various morphologic techniques, including electron microscopy, the in situ end-labeling technique, and immunohistochemistry to confirm the caspase-cleaved keratin 18 rearrangements.

Adenoma↗
PubMed2001

Gliomatosis cerebri: intra vitam stereotactic determination in two cases and review of the literature.

Gliomatosis cerebri (GC) is an infiltrative neoplastic process that is diffusely distributed through neural structures, whose anatomical configuration remains intact. Most of the cases with GC reported in the literature were diagnosed at autopsy (101/110, 92%). We report two cases of GC in a 42-year-old woman and a 65-year-old man. The diagnosis was confirmed neuropathologically after MRI-guided stereoetactic biopsy. External radiation therapy was performed and led to a complete recovery of all clinical signs. Follow-up examinations 17 and 21 months after diagnosis showed permanent reversal of all clinical and radiological signs. MRI should be used as a primary imaging study in the evaluation of GC and for the determination of the target points for stereotactic biopsy. We discuss the aetiology, clinical manifestation, difficulties of intra vitam diagnosis, and management of this rare condition in the light of other 110 (101 postmortem and nine intra vitam) reported cases of GC in the literature.

Adult↗
PubMed1987

The serum carnitine status of cancer patients.

Carnitine is necessary for the translocation of fatty acids into the mitochondria, and the relative concentration of carnitine and acylcarnitine in the serum are known to reflect metabolic states. A survey of serum carnitine concentrations was made in 54 cancer and 81 noncancer patients for the purpose of determining the carnitine profile. The total carnitine, nonesterified carnitine, and acid-insoluble acylcarnitine concentrations of cancer patients were similar to noncancer patients and within the normal range; however, the acid-soluble acylcarnitine concentration was significantly lower in cancer patients than in controls (6.7 vs 11.5 nmol/ml). When percentages and ratios were calculated for the relative proportions of acylcarnitines, large variations were found to occur among cancer types. The acylcarnitine ratio (the sum of acid-soluble and acid-insoluble acylcarnitine divided by nonesterified carnitine) ranged from 0.17 in leukemia to 0.30 in breast cancer cases. Since the acylcarnitine concentration and ratio are reflective of the metabolic state, the depressed acylcarnitine ratio in cancer patients may be due to decreased production, increased utilization, or increased excretion of acid-soluble acylcarnitine. Elevated concentrations of nonesterified carnitine and total carnitine were observed in two patients, and some of the lowest acylcarnitine concentrations and ratios were observed in advanced cancer cases. The therapeutic regimen and/or the neoplastic process itself may be responsible for the observed differences in the serum carnitine profile.

Adult↗