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At least 1,009 records · Page 56Linked to original sources
PubMed2005

Accumulation of plasma cells expressing CXCR3 in the synovial sublining regions of early rheumatoid arthritis in association with production of Mig/CXCL9 by synovial fibroblasts.

Accumulation of plasma cells in the synovium is one of the diagnostic hallmarks in the histopathological manifestations of rheumatoid arthritis (RA). This seems to be prominent even prior to significant B cell infiltration and/or formation of lymphoid follicles in the synovium. To clarify the mechanism of early plasma cell accumulation, we examined in situ expression of chemokines and their receptors using synovial targeting biopsy specimens, which were obtained under arthroscopy from early RA patients. By immunohistochemical staining, plasma cells were found to express a chemokine receptor CXCR3, while synovial fibroblasts in the synovial sublining regions expressed its ligand, Mig/CXCL9. By reverse transcription-polymerase chain reaction (RT-PCR), using targeted lesions of synovial tissues obtained by laser capture microdissection, expression levels of Mig/CXCL9 in the synovial sublining regions were remarkably high and were likely to be associated with interferon (IFN)-gamma expression. Furthermore, cultured synovial fibroblasts were confirmed to produce Mig/CXCL9 upon stimulation with IFN-gamma. Our results indicate that in the early stage of RA, plasma cells expressing CXCR3 may be recruited directly from the circulation into the synovial sublining regions by its ligand, Mig/CXCL9, produced by synovial fibroblasts.

Adult↗
PubMed1982

The glucose/glucose-6-phosphate cycle in the periportal and perivenous zone of rat liver.

Periportal and perivenous hepatocytes contain different activities (V) of antagonistic key enzymes such as glucokinase and glucose-6-phosphatase. In order to get an insight into the metabolism of the periportal and perivenous area the flux rates (v) of the glucose/glucose-6-phosphate cycle were calculated on the basis of the Michaelis-Menten equation using the measured zonal concentrations of glucose and glucose 6-phosphate, the zonal activities of glucokinase and glucose-6-phosphatase previously reported and the half-saturating substrate concentrations (Km) of the two enzymes found in the literature. The concentrations of glucose were obtained as a first approximation by measuring the concentrations in portal (= periportal) and hepatovenous (= perivenous) blood; those of glucose 6-phosphate were calculated from the levels determined in microdissected periportal and perivenous liver tissue. The calculations showed (a) that the overall cycling rates agreed remarkably well with those reported for intact animals and (b) that during a normal feeding rhythm the periportal zone should catalyze net glucose output and the perivenous zone should mediate net glucose uptake, as proposed by the model of 'metabolic zonation'.

Animals↗
PubMedDate not supplied

Loss of the tumor suppressor p53 gene at the liver cirrhosis stage in Japanese patients with hepatocellular carcinoma.

The incidence of p53 gene aberrations is reported to be about 20-50% in hepatocellular carcinomas (HCCs). In most cases, HCC is clinically preceded by liver cirrhosis, but the genetic changes in cirrhosis are not known well. Therefore, we studied the loss of heterozygosity (LOH) of the p53 gene in cirrhotic and neoplastic foci in the livers of patients with HCC. To assess the relationship between the LOH status of the p53 gene in the liver cirrhosis stage and that in HCC, we analyzed the samples microdissected from paraffin-embedded tissues using the polymerase-chain-reaction-based assay. We studied 18 patients with HCC. Fourteen of the 18 cases showed constitutional heterozygosity for the microsatellite markers. In 8 (57%) of the 14 informative cases, LOH was detected in primary HCCs. Among these 8 doubly informative (informative and LOH positive in primary HCC) cases, 5 cases (63%) showed LOH in liver cirrhosis lesions. The pattern of p53 allelic loss in the cirrhotic foci was identical with that in the corresponding tumor. The remaining 6 cases without LOH of the p53 gene in HCC showed on p53 loss in any cirrhotic foci. LOH of the p53 gene may occur before the development of HCC.

Aged↗
PubMed2003

Upregulation of chemokine expression in the retinal vasculature in ischemia-reperfusion injury.

PURPOSE: To evaluate chemokine expression at various retinal sites after ischemia-reperfusion injury, using reverse transcription-polymerase chain reaction (RT-PCR) analysis of selected tissue obtained by laser capture microdissection. METHODS: Retinal ischemia was produced in Lewis rats by increasing intraocular pressure for 75 minutes. At 3, 6, 12, and 24 hours after reperfusion, RT-PCR was used to measure the levels of monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, interleukin (IL)-8, and interferon-gamma-inducible 10-kDa protein (IP-10) mRNA expression in the ganglion cell layer (GCL), inner nuclear layer (INL), outer nuclear layer (ONL), and retinal vessels, after laser capture microdissection of these retinal layers. These chemokines were further localized by immunohistochemical methods, using antibodies specific to MCP-1 and MIP-1alpha. Leukocyte infiltration into the retina was detected with immunostaining for leukocyte common antigen. RESULTS: Ischemia-reperfusion induced expression of MCP-1, MIP-1alpha, and MIP-1beta mRNA in the retinal vessels 3 hours after reperfusion. Six hours after reperfusion, expression of these chemokines and IL-8 mRNA was seen in the GCL and INL. Twelve hours after reperfusion, IP-10 mRNA expression was seen in the GCL and INL. Immunoreactive MCP-1 and MIP-1alpha were detected in the GCL, INL, and the retinal vessels 24 hours after reperfusion. No chemokine mRNA expression or immunoreactivity was detected in the ONL at any time. Leukocyte infiltration was noted at 12 hours, increasing markedly 24 hours after reperfusion. CONCLUSIONS: Ischemia-reperfusion retinal injury results in generation of highly chemotactic agents, initially in the retinal vasculature, then in the other inner retinal layers. Such differential chemokine expression may play a role in leukocyte recruitment and selective leukocyte infiltration in the inner retina, leading to retinal damage primarily localized to the ganglion cells and other inner neuronal structures.

Animals↗
PubMed2006

Quantitative real-time RT-PCR of CD24 mRNA in the detection of prostate cancer.

BACKGROUND: Gene expression profiling has recently shown that the mRNA for CD24 is overexpressed in prostate carcinomas (Pca) compared to benign or normal prostate epithelial tissues. Immunohistochemical studies have reported the usefulness of anti-CD24 for detecting prostate cancer over the full range of prostate specimens encountered in surgical pathology, e.g. needle biopsies, transurethral resection of prostate chips, or prostatectomies. It is a small mucin-like cell surface protein and thus promises to become at least a standard adjunctive stain for atypical prostate biopsies. We tested the usefulness of real-time RT-PCR for specific and sensitive detection of CD24 transcripts as a supplementary measure for discriminating between malignant and benign lesions in prostatic tissues. METHODS: Total RNA was isolated from snap-frozen chips in 55 cases of benign prostatic hyperplasia (BPH) and from frozen sections in 59 prostatectomy cases. The latter contain at least 50% malignant epithelia. Relative quantification of CD24 transcripts was performed on the LightCycler instrument using hybridization probes for detection and porphobilinogen deaminase transcripts (PBGD) for normalization. RESULTS: Normalized CD24 transcript levels showed an average 2.69-fold increase in 59 Pca-cases (mean 0.21) when compared to 55 cases of BPH (mean 0.08). This difference was highly significant (p < 0.0001). The method has a moderate specificity (47.3%) but a high sensitivity (86.4%) if the cutoff is set at 0.0498. CD24 expression levels among Pca cases were not statistically associated with the tumor and lymph-node stage, the grading (WHO), the surgical margins, or the Gleason score. CONCLUSION: The present study demonstrates the feasibility of quantitative CD24 RNA transcript detection in prostatic tissues even without previous laser microdissection.

Adenocarcinoma↗
PubMed2006

Somatic deletion of the NF1 gene in a neurofibromatosis type 1-associated malignant melanoma demonstrated by digital PCR.

BACKGROUND: Neurofibromatosis type 1 (NF1) is the most common hereditary neurocutaneous disorder and it is associated with an elevated risk for malignant tumors of tissues derived from neural crest cells. The NF1 gene is considered a tumor suppressor gene and inactivation of both copies can be found in NF1-associated benign and malignant tumors. Melanocytes also derive from neural crest cells but melanoma incidence is not markedly elevated in NF1. In this study we could analyze a typical superficial spreading melanoma of a 15-year-old boy with NF1 for loss of heterozygosity (LOH) within the NF1 gene. Neurofibromatosis in this patient was transmitted by the boy's farther who carried the mutation NF1 c. 5546 G/A. RESULTS: Melanoma cells were isolated from formalin-fixed tissue by liquid coverslip laser microdissection. In order to obtain statistically significant LOH data, digital PCR was performed at the intragenic microsatellite IVS27AC28 with DNA of approx. 3500 melanoma cells. Digital PCR detected 23 paternal alleles and one maternal allele. Statistical analysis by SPRT confirmed significance of the maternal allele loss. CONCLUSION: To our knowledge, this is the first molecular evidence of inactivation of both copies of the NF1 gene in a typical superficial spreading melanoma of a patient with NF1. The classical double-hit inactivation of the NF1 gene suggests that the NF1 genetic background promoted melanoma genesis in this patient.

Adolescent↗
PubMed2005

Early correlation of microglial activation with enhanced tumor necrosis factor-alpha and monocyte chemoattractant protein-1 expression specifically within the entorhinal cortex of triple transgenic Alzheimer's disease mice.

BACKGROUND: Alzheimer's disease is a complex neurodegenerative disorder characterized pathologically by a temporal and spatial progression of beta-amyloid (Abeta) deposition, neurofibrillary tangle formation, and synaptic degeneration. Inflammatory processes have been implicated in initiating and/or propagating AD-associated pathology within the brain, as inflammatory cytokine expression and other markers of inflammation are pronounced in individuals with AD pathology. The current study examines whether inflammatory processes are evident early in the disease process in the 3xTg-AD mouse model and if regional differences in inflammatory profiles exist. METHODS: Coronal brain sections were used to identify Abeta in 2, 3, and 6-month 3xTg-AD and non-transgenic control mice. Quantitative real-time RT-PCR was performed on microdissected entorhinal cortex and hippocampus tissue of 2, 3, and 6-month 3xTg-AD and non-transgenic mice. Microglial/macrophage cell numbers were quantified using unbiased stereology in 3xTg-AD and non-transgenic entorhinal cortex and hippocampus containing sections. RESULTS: We observed human Abeta deposition at 3 months in 3xTg-AD mice which is enhanced by 6 months of age. Interestingly, we observed a 14.8-fold up-regulation of TNF-alpha and 10.8-fold up-regulation of MCP-1 in the entorhinal cortex of 3xTg-AD mice but no change was detected over time in the hippocampus or in either region of non-transgenic mice. Additionally, this increase correlated with a specific increase in F4/80-positive microglia and macrophages in 3xTg-AD entorhinal cortex. CONCLUSION: Our data provide evidence for early induction of inflammatory processes in a model that develops amyloid and neurofibrillary tangle pathology. Additionally, our results link inflammatory processes within the entorhinal cortex, which represents one of the earliest AD-affected brain regions.

Journal Article↗
PubMed2005

The estrogen receptor-alpha A908G (K303R) mutation occurs at a low frequency in invasive breast tumors: results from a population-based study.

INTRODUCTION: Evidence suggests that alterations in estrogen signaling pathways, including estrogen receptor-alpha (ER-alpha), occur during breast cancer development. A point mutation in ER-alpha (nucleotide A908G), producing an amino acid change from lysine to arginine at codon 303 (K303R) results in receptor hypersensitivity to estrogen. This mutation was initially reported in one-third of hyperplastic benign breast lesions, although several recent studies failed to detect it in benign or malignant breast tissues. METHODS: We screened 653 microdissected, newly diagnosed invasive breast tumors from patients in the Carolina Breast Cancer Study, a population-based case-control study of breast cancer in African American and white women in North Carolina, for the presence of the ER-alpha A908G mutation by using single-strand conformational polymorphism (SSCP) analysis and 33P-cycle sequencing. RESULTS: We detected the ER-alpha A908G mutation in 37 of 653 (5.7%) breast tumors. The absence of this mutation in germline DNA confirmed it to be somatic. Three tumors exhibited only the mutant G base at nucleotide 908 on sequencing, indicating that the wild-type ER-alpha allele had been lost. The ER-alpha A908G mutation was found more frequently in higher-grade breast tumors (odds ratio (OR) 2.83; 95% confidence interval (CI) 1.09 to 7.34, grade II compared with grade I), and in mixed lobular/ductal tumors (OR 2.10; 95% CI 0.86 to 5.12) compared with ductal carcinomas, although the latter finding was not statistically significant. CONCLUSION: This population-based study, the largest so far to screen for the ER-alpha A908G mutation in breast cancer, confirms the presence of the mutant in invasive breast tumors. The mutation was associated with higher tumor grade and mixed lobular/ductal breast tumor histology.

Amino Acid Substitution↗
PubMed2004

Heterogeneity in the distribution of RET/PTC rearrangements within individual post-Chernobyl papillary thyroid carcinomas.

The nuclear disaster that occurred in Chernobyl in 1986 offered the unique opportunity to study the molecular genetics of one human tumor type, papillary carcinoma of the thyroid gland, associated with a specific etiology. We have analyzed RET rearrangements in post-Chernobyl papillary thyroid carcinomas (n = 29), follicular thyroid adenomas (n = 2), and follicular thyroid carcinoma (n = 1) by interphase fluorescence in situ hybridization (FISH) analysis on paraffin-embedded tissue sections. Paraffin sections were microdissected before use to ensure that only tumor was present. Cell nuclei were scored for the presence of a split FISH signal (separated red and green signal) in addition to an overlapping signal. Only cells with either two overlapping signals or one split and one overlapping signal were counted to ensure that only complete cell nuclei had been scored. In total, 23 of 32 cases (72%) showed RET rearrangements diagnosed by FISH interphase analysis. In all cases, the tumors were composed of a mixture of cells with and without ret rearrangement on FISH. In some cases, this distribution was clearly nonrandom because clustering of rearranged cells was detected within the same tumor nodule. Accordingly, only 31% of the cases positive for rearrangement on FISH also scored positive using RT-PCR. These findings suggest that because RET/PTC rearrangements are not present in a majority of tumor cells, either a fraction of post-Chernobyl papillary thyroid tumors are of multiclonal origin, or ret rearrangement is a later, subclonal event.

Adolescent↗
PubMed2006

Loss of MAL expression in precancerous lesions of the esophagus.

BACKGROUND: We have identified a novel function of MAL (T-cell differentiation-related gene) as a candidate suppressor gene in esophageal cancer. As the role of MAL expression in esophageal carcinogenesis is as yet undetermined, MAL expression in a rat multi-step carcinogenic model and in precancerous lesions of the human esophagus was investigated. Microarray analysis between MAL-transfectant and control cells was also carried out to clarify how MAL confers its anti-tumor effects. MATERIALS AND METHODS: (1) In the rat model, MAL expression levels in laser microdissected normal esophageal epithelium, dysplastic tissues and carcinoma tissues were examined by reverse transcription (RT)-PCR. (2) Immunostaining with MAL antibody was performed in 10 dysplastic lesions adjacent to cancer in six cases of esophageal cancer. (3) We established a MAL transfectant using a Tet-off vector in esophageal cancer cells and performed microarray analysis under MAL-positive and MAL-negative conditions. RESULTS: (1) In the rat model, MAL mRNA expression was observed only in the normal samples. (2) MAL expression was observed distinctively in differentiated or keratinized normal tissues and was not observed in either dysplastic lesions or carcinoma tissue. (3) Up-regulated genes in MAL-positive cells included keratin 18 (transfectant/control = 2.94) and keratin 10 (t/c = 2.82). CONCLUSION: MAL expression was lost in dysplastic lesions of the rat carcinoma model as well as the human esophagus. The up-regulated keratins revealed by microarray analysis and the strong staining of the differentiated normal tissues in immunohistochemical study support the role of MAL as a regulator of differentiation in esophageal epithelium.

Animals↗
PubMed2000

Genetic Changes in Chromosomes 1p and 17p in Thyroid Cancer Progression.

Little is known about the genetic alterations that occur during the progression of thyroid neoplasms. To understand better the biology of thyroid tumors, we investigated several genetic loci in benign and malignant thyroid neoplasms. Forty-one thyroid tumors (6 adenomas, 16 papillary, 14 follicular, and 5 anaplastic carcinomas) were studied. Normal and tumor cells were microdissected from paraffin-embedded tissues. DNA was used for polymerase chain reaction-based loss of heterozygosity (LOH) analysis with the following markers: D1S243 (1p35-36), D1S165 (1p36) and D1S162 (1p32), TP53 (17p13), and INT-2 (11q13). Immunohistochemistry for Ki-67 was performed. The Ki-67 labeling index (LI) was the percentage of positive tumor cells. LOH at 1p was seen in 2 of 5 (40%) informative cases of anaplastic carcinoma (2 of 2 at D1S162 and 1 of 2 at D1S165) and in 2 of 11 (18%) informative cases of follicular carcinoma (2 of 7 at D1S243, 2 of 7 at D1S1654, and 1 of 6 at D1S162). One anaplastic (20%) and two follicular carcinomas (14%) had LOH in at least two of the 1p loci analyzed. None of the adenomas and papillary carcinomas had LOH at these loci. LOH at 17p and 11q13 were infrequent. Ki-67 LI was 1.4, 7, 16, and 65% in adenomas, papillary, follicular, and anaplastic carcinomas, respectively. Allelic loss at 1p may occur in aggressive types of thyroid carcinoma and may be a marker of poor prognosis. LOH at 1p may represent a late genetic event in thyroid carcinogenesis. LOH at 17p and 11q13 (MEN gene locus) is uncommon in thyroid neoplasms.

Journal Article↗
PubMed2004

Biomarker identification in neurologic diseases: improving diagnostics and therapeutics.

Identification of biomarkers in neurological disease remains impeded by many obstacles. Among them are the availability of tissue at the site of pathology, poor clinical diagnostics, the complexity of the brain and a general dearth of functional end points and models for validation. However, advances in technology have helped to overcome these challenges. Some of these advances include standardization and increased efficiency in brain banking, novel techniques for brain imaging, improved methods for reducing tissue heterogeneity including laser capture microdissection, high-throughput genomics, new functional validation techniques such as RNA interference, and the development of new animal models of neurologic disease. In order to efficiently handle the wealth of information that will be gleaned from these new technologies, new integrated databasing protocols will be necessary. Access to these databases by researchers and clinicians is critical to the continued progress being made in biomarker identification in neurological disease. These challenges and ways to overcome them are presented here in the context of a disease known to be a robust model for biomarker identification, Alzheimer's disease.

Biomarkers↗
PubMed2005

Clinical implications of promoter hypermethylation in RASSF1A and MGMT in retinoblastoma.

We investigated the epigenetic silencing and genetic changes of the RAS-associated domain family 1A (RASSF1A) gene and the O6-methylguanine-DNA methyltransferase (MGMT) gene in retinoblastoma. We extracted DNA from microdissected tumor and normal retina tissues of the same patient in 68 retinoblastoma cases. Promoter methylation in RASSF1A and MGMT was analyzed by methylation-specific PCR, RASSF1A sequence alterations in all coding exons by direct DNA sequencing, and RASSF1A expression by RT-PCR. Cell cycle staging was analyzed by flow cytometry. We detected RASSF1A promoter hypermethylation in 82% of retinoblastoma, in tumor tissues only but not in adjacent normal retinal tissue cells. There was no expression of RASSF1A transcripts in all hypermethylated samples, but RASSF1A transcripts were restored after 5-aza-2'-deoxycytidine treatment with no changes in cell cycle or apoptosis. No mutation in the RASSF1A sequence was found. MGMT hypermethylation was present in 15% of the retinoblastoma samples, and the absence of MGMT hypermethylation was associated (P = .002) with retinoblastoma at advanced Reese-Ellsworth tumor stage. Our results revealed a high RASSF1A hypermethylation frequency in retinoblastoma. The correlation of MGMT inactivation by promoter hypermethylation with lower-stage diseases indicated that MGMT hypermethylation provides useful prognostic information. Epigenetic mechanism plays an important role in the progression of retinoblastoma.

Cell Cycle↗
PubMed2006

Whole transcriptome amplification for gene expression profiling and development of molecular archives.

Expression profiling of clinically obtainable tumor specimens has been hindered by the need for microgram quantities of RNA. In vitro transcription (IVT)-based amplifications are most commonly used to amplify small quantities of RNA for microarray analysis. However, significant drawbacks exist with IVT-based amplification, and the need for alternative amplification methods remains. Herein, we validate whole transcriptome amplification (WTA), an exponential amplification technique that produces cDNA libraries and amplified target in 3 to 4 hours from nanogram quantities of total RNA using a combination of cDNA microarrays and quantitative polymerase chain reaction (PCR). We demonstrate that WTA material can serve as a "molecular archive" because a WTA cDNA library can be faithfully amplified through multiple rounds of PCR amplification, allowing it to serve as a bankable and distributable resource. To demonstrate applicability, WTA was combined with laser capture microdissection to profile frozen prostate tissues. Unlike most IVT-based and exponential amplification techniques, WTA does not depend on the presence of a poly-A tail. Thus, we demonstrate that WTA is compatible with artificially degraded RNA and RNA isolated from formalin-fixed paraffin-embedded tissues. Taken together, WTA represents a versatile approach to profile and archive cDNA from minute tumor samples and is compatible with partially degraded RNA.

Biological Specimen Banks↗
PubMed2003

Adrenal ganglioneuroma in a patient presenting with severe hypertension and diarrhea.

Ganglioneuromas (GNs) are neural crest cell-derived tumors and rarely occur in the adrenal gland. There are presently no markers that can reliably distinguish benign and malignant neuroendocrine tumors. Here we describe a 63-year-old woman who developed sudden chest pain and hypertension combined with increased stool frequency. An incidental adrenal mass 5 cm in size with a bright signal on T2-weighted magnetic resonance imaging was discovered. Biochemical evaluation and (131)I-metaiodobenzylguanidine (MIBG) scintigraphy were negative. Histopathological examination revealed a mature adrenal GN. Neuroblastoma, the immature form of a GN, is known for deletions on chromosomal locus 1p36, and adrenal tumors frequently show allele loss on 17p. To further elucidate the histo- and pathogenesis of adrenal GN, we performed loss of heterozygosity studies on chromosomal loci 1p34-36 and 17p13 (the p53 gene locus) after careful microdissection of tumor and normal tissue. We did not detect allelic losses at these loci with the informative polymorphic markers used, suggesting that these loci are not involved in tumorigenesis. In addition, immunohistochemical investigation of the GN was positive for vasoactive intestinal peptide, a hormone commonly expressed in ganglion cells. We suggest that in our patient with an adrenal GN, the combination of biochemical, scintigraphic, molecular, immunohistochemical, and histopathological findings are all consistent with the benign morphology of this tumor.

Adrenal Gland Neoplasms↗
PubMed2004

The role of microsatellite instability at chromosome 11p15.5 in the progression of breast ductal carcinoma.

The study of microsatellite instability (MSI) has provided the evidence to support a sequential, progressive pathway for the development of cancer. In this study, we analyzed the role of MSI at chromosome 11p15.5 using microdissection of paraffin-embedded tissue from 68 matched normal and breast tumor samples. Components of intraductal, invasive and metastatic foci in lymph node were assessed for MSI using the polymorphic markers D11S922, tyrosine hydroxylase (TH) and D11S988. We found that MSI at D11S922 was relatively high incidence than other two markers and increased during breast cancer progression. The overall frequency of MSI at D11S922 was 26.7% in pure intraductal carcinoma, 36.4% in invasive carcinoma, and 40.0% in invasive carcinoma with metastases. We observed no significant correlation between MSI at chromosome 11p15.5 and the patient's age, tumor size, histological grade, or lymph node metastasis. We compared the MSI incidence with the expression of prognostic markers, such as p53, c-erb B2, estrogen receptor, and progesterone receptor, and found no significant correlation. We suggest that the MSI of chromosome 11p15.5 is increased during breast cancer progression, but long-term follow-up study would establish whether MSI at chromosome 11p15.5 could be useful as a potential prognostic marker for breast cancer.

Breast Neoplasms↗
PubMed1999

Microsatellite instability in hyperplastic and adenomatous polyps of the stomach.

BACKGROUND: Few studies have focused on the presence and significance of microsatellite instability (MSI) in gastric polyps, and the results on record are conflicting. The aim of the current study was to address this issue, taking into consideration the 2 main types of gastric polyps, the coexistence of foci of malignant transformation, and the expression of p53 and ERBB-2. METHODS: Six hyperplastic polyps, 10 adenomatous polyps, and 4 adenomatous polyps displaying foci of malignant transformation (intestinal-type carcinoma) were studied for MSI. The authors analyzed a mononucleotide repeat microsatellite (BAT-26) and 5 dinucleotide repeats in microdissected formalin fixed, paraffin embedded tissue sections that were representative of the lesions. Expression of p53 and ERBB-2 were evaluated by immunohistochemistry. RESULTS: BAT-26 positivity was detected in 1 of 6 hyperplastic polyps (16.7%) and in 2 of 10 adenomas (20%) without malignant transformation. In the 4 adenomatous polyps with carcinomatous foci, BAT-26 positivity was detected in 2 cases (50%) in both (adenomatous and carcinomatous) components of the lesions. p53 immunoreactivity was observed in 6 adenomatous polyps, 2 of them with malignant transformation. Overexpression of the ERBB-2 protein was detected in 1 adenomatous polyp with malignant transformation. CONCLUSIONS: Replication error (RER+) phenotype occurs in both hyperplastic and adenomatous polyps of the stomach. The highest frequency is observed in adenomatous polyps with carcinomatous foci, suggesting that MSI may play a role in the process of malignant transformation in this setting. No significant association was observed between RER+ phenotype and overexpression of p53 or ERBB-2 proteins.

Adenomatous Polyps↗
PubMed2002

Alterations of p16(INK4a) and p14(ARF) in patients with severe oral epithelial dysplasia.

A number of genetic aberrations have been reported in end-stage squamous cell carcinoma of the head and neck, including p16(INK4a) and p14(ARF) (INK4a/ARF) inactivation rates of 70-85%. Still, the cell cycle-regulatory genes p16(INK4a) and p14(ARF) remain poorly understood in oral cavity premalignant lesions. This study evaluated INK4a/ARF locus alterations in 26 patients (28 samples) deemed to be at increased risk for malignant transformation to squamous cell carcinoma due to the diagnosis of severe oral epithelial dysplasia. Microscopically confirmed dysplastic oral epithelium and matching normal tissue were laser capture-microdissected from paraffin sections, DNA was isolated, and molecular techniques were used to evaluate p16(INK4a) and p14(ARF) gene deletion, mutation, loss of heterozygosity (LOH), and hypermethylation events. Deletion of exon 1beta, 1alpha, or 2 was detected in 3.8%, 11.5%, and 7.7% of patients, respectively. INK4a and ARF mutations were detected in 15.4% and 11.5% of patients with severe dysplasia of the oral epithelium. All identified mutations occurred in the INK4a/ARF conserved exon 2. Allelic imbalance was assessed using three markers previously reported to show high LOH rates in head and neck tumors. LOH was found in 42.1%, 35.0%, and 82.4% of patients for the markers IFNalpha, D9S1748, and D9S171, respectively. Hypermethylation of p16(INK4a) and p14(ARF) was detected in 57.7% and 3.8% of patients, respectively, using nested, two-stage methylation-specific PCR. The highest rates of p16(INK4a) hypermethylation occurred in lesions of the tongue and floor of the mouth. In addition, p16(INK4a) hypermethylation was significantly linked to LOH in two or more markers. These data support that INK4a/ARF locus alterations are frequent events preceding the development of oral cancer and that p16(INK4a) inactivation occurs to a greater extent in oral dysplasia than does p14(ARF) inactivation.

Adult↗