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PubMed2005

Frequent c-Kit gene mutations not only in gastrointestinal stromal tumors but also in interstitial cells of Cajal in surrounding normal mucosa.

Gastrointestinal stromal tumors (GISTs) are thought to originate from mesenchymal stem cells that differentiate toward the interstitial cells of Cajal (ICCs). The frequent occurrence of activating mutations involving exon 11 of c-Kit gene in sporadic GISTs indicates an important role in genesis of this tumor type. In the present study we examined c-Kit gene mutations in a series of GISTs and also in ICCs of surrounding normal tissues. Samples from 18 patients were monitored immunohistochemically for c-Kit expression and microdissected for sequencing analysis of exons 9, 11, 13, and 17 of the c-Kit gene. It was revealed to be mutated in exon 11 or adjacent introns in 9 out of the total of 18 (50.0%) GISTs. In 6 (33.3%) cases, mutations in ICCs were also detected in the same exon. With stomach GISTs, 8 of 16 (50.0%) cases harbored mutations and 4 had mutations in background ICCs (25.0%). In contrast counterpart ICCs in gastric cancer cases harbored no c-Kit gene mutations (0 out of 24=0%) (P<0.02). ICCs undergoing c-Kit mutation as a possible early initiation step in GIST tumorigenesis may thus have pre-neoplastic potential.

Adult↗
PubMed1992

Human papillomavirus types 16 and 18 are not involved in human prostate carcinogenesis: analysis of archival human prostate cancer specimens by differential polymerase chain reaction.

Human papilloma viruses (HPV) have been implicated in the pathogenesis of a variety of malignancies, especially in carcinomas of the female genital tract. Recently, based on observations using the polymerase chain reaction amplification assay, HPV types 16 and 18 specific DNA sequences have been detected in prostate cancer specimens obtained by transurethral resection. Since HPV types 16 and 18 have been shown to possess oncogenic potential, an association between HPV infection and prostatic carcinoma has been suggested. In order to exclude potentially HPV-colonized urethral mucosa from analysis and restrict our study to predominantly malignant tissue, cancerous areas from a series of 30 paraffin-embedded prostate adenocarcinomas were microdissected and analyzed for the presence of HPV 16 or HPV 18 specific sequences by a modification of PCR (D-PCR) and Southern blot analysis. Despite the high sensitivity of our analytical technique, we found no evidence of HPV-DNA of either type in any of the 30 primary prostate cancers. In contrast, both HPV 16 (2/8 specimens) and HPV 18 (2/8 specimens) DNA was detected in randomly chosen cervical carcinomas using the D-PCR methodology. Our data would indicate that the oncogenic HPV-types 16 and 18 are unlikely effectors of prostate carcinogenesis.

Adenocarcinoma↗
PubMed1998

Evidence of independent origin of multiple tumors from patients with prostate cancer.

BACKGROUND: In men with prostate cancer, the gland usually contains two or more widely separate tumors. A critical issue of prostatic carcinogenesis is whether these multiple tumors are independent in origin. Molecular analysis of microsatellite (i.e., highly repeated, short nucleotide sequences) alterations in the DNA from separate tumors in the same prostate can be used to determine whether or not these separate tumors arise independently. METHODS: Four microsatellite polymorphic markers (D8S133, D8S136, and D8S137, for a putative tumor suppressor gene on chromosome 8p, and D17S855, for the BRCA1 gene on chromosome 17q) were used to examine the pattern of allelic loss in prostate cancer from 19 patients who had two or more distantly separate tumors (i.e., located on contralateral sides or separated by at least half the anterior-posterior diameter of the prostate). Forty distantly separate tumors were microdissected, DNA samples were prepared from formalin-fixed, paraffin-embedded wholemount prostate tissue section, and the overall frequencies of loss of heterozygosity at the four loci were determined. RESULTS: The pattern of allelic loss was compatible with independent tumor origin in 15 of 18 informative cases. A random discordant pattern of allelic deletion was observed in distantly separate tumors, whereas the same allele was consistently lost in cells from different regions of the same tumor. For three patients, the results were compatible with either intraglandular dissemination or independent origin of prostate cancer. CONCLUSIONS: Our data suggest that multiple tumors in some patients with prostate cancer have independent origin.

Chromosome Deletion↗
PubMed2004

Inflammatory mechanisms contributing to pancreatic cancer development.

OBJECTIVE: Pancreatic cancer is the most deadly of all gastrointestinal (GI) malignancies, yet relatively little is known regarding mechanisms of tumor development including the role of inflammation. SUMMARY BACKGROUND DATA: Chronic pancreatitis (CP) increases the risk of developing cancer by 10- to 20-fold; mediators of the chronic inflammatory process and the surrounding fibrotic stroma likely support a transformation to malignancy, yet the exact mechanisms remain undefined. The purpose of our present study was to determine potential inflammatory components in epithelial and stromal cells that may contribute to both CP and pancreatic cancers. METHODS: Specimens of normal pancreas, CP, and pancreatic cancer were examined using laser-capture microdissection (LCM), gene array, and immunohistochemistry. RESULTS: Gene array analysis from LCM-dissected tissues demonstrated: (i) increased expression of interleukin-8 (IL-8), an activator of the inflammatory factor nuclear factor-kappaB (NF-kappaB), and (ii) decreased expression of IkappaB (an inhibitor of NF-kappaB) in CP ductal cells compared with normal ducts. Compared with CP, cancers demonstrated: (i) increased expression of tumor related genes including S100A4, cyclin E1, and epidermal growth factor (EGF) receptor, and (ii) expression of matrix metalloproteinase 2, a pro-invasive factor for tumor cells, which was not present in the CP stroma. Increased staining of both the p50 NF-kappaB subunit and IKKalpha kinase (a protein that allows activation of NF-kappaB) was noted in CP and cancers. CONCLUSIONS: Our results demonstrate that similar inflammatory components and downstream effectors are present in CP and pancreatic cancers. Importantly, these findings suggest that a common pathway for pancreatic cancer development may be through a chronic inflammatory process including stroma formation. These findings may lead to novel strategies for pancreatic cancer prophylaxis based on inhibition of inflammatory mediators.

Biomarkers, Tumor↗
PubMed2006

Cdx-2 expression in squamous and metaplastic columnar epithelia of the esophagus.

The molecular pathogenesis of Barrett's esophagus is poorly understood. Evidence suggests that at a phenotypic level, the metaplastic process begins with the transformation of squamous epithelium in the distal esophagus to cardiac mucosa, which subsequently becomes intestinalized. The homeobox gene Cdx-2 has been shown to be an important transcriptional regulator of embryonic differentiation and maintenance of adult intestinal type epithelium. We hypothesized that Cdx-2 gene expression levels increase with the phenotypic transformation of normal squamous mucosa to the intestinalized columnar mucosa of Barrett's esophagus. Endoscopic biopsies were obtained at the gastroesophageal junction in patients with symptoms of gastroesophageal reflux disease and classified according to histology: normal squamous mucosa (n = 62), cardiac mucosa (n = 19), oxynto-cardiac mucosa (n = 14), and intestinal metaplasia (n = 15). Duodenal biopsies (n = 26) served as the columnar control. After laser capture microdissection and RNA isolation, gene expression levels of Cdx-2 were measured in each tissue type by quantitative reverse transcription polymerase chain reaction. Consistent with its known function, Cdx-2 gene expression levels were highest in duodenal mucosa and nearly absent in squamous epithelium. There was a stepwise increase in Cdx-2 gene expression from cardiac to Barrett's epithelium (P < 0.001). Expression levels of Cdx-2 in cardiac and oxynto-cardiac mucosa were 40-70 times higher and Barrett's mucosa 400 times higher than that found in squamous epithelium. Relative expression of the homeobox gene Cdx-2, known to induce differentiation of intestinal type epithelium, increases in a stepwise fashion during the phenotypic transformation of distal esophageal squamous mucosa to cardiac columnar mucosa and to the intestinalized columnar mucosa of Barrett's esophagus. Therefore, Cdx-2 may be a potential biomarker to detect the early transition to Barrett's esophagus.

Adolescent↗
PubMed2000

Glucagon-like peptide-2 increases sucrase-isomaltase but not caudal-related homeobox protein-2 gene expression.

To determine the effect of glucagon-like peptide-2 (GLP-2) on sucrase-isomaltase and caudal-related homeobox protein-2 (Cdx-2) gene expression, male Wistar rats were divided into total parenteral nutrition (TPN)-fed and GLP-2-treated, TPN-fed groups. TPN was given via a jugular line, inserted under anesthesia, for 7 days. The treatment group received 40 microg/day of GLP-2 intravenously with the TPN diet. The small intestine and colon were weighed and measured. Tissue was obtained from the jejunum, terminal ileum, and midcolon. RNA analysis, morphometry, and microdissection were performed. The weight of the small intestine of GLP-2-treated rats was greater than that of TPN-fed rats (P < 0.001). GLP-2 increased the mean metaphase arrests/crypt in both the jejunum and ileum (P < 0.001). Ileal expression of sucrase-isomaltase was increased by 1. 6-fold (P < 0.05). Jejunal expression was increased by a similar amount, although not significantly (P = 0.08). There was no change in Cdx-2 gene expression. Thus GLP-2 can maintain small intestinal morphology and function, but effects on gene expression are not mediated by gross changes in the level of the mRNA for the homeobox protein Cdx-2.

Animals↗
PubMedDate not supplied

Growth, immortalization, and differentiation potential of normal adult human proximal tubule cells.

Human proximal tubule epithelial cell lines are potentially useful models to elucidate the complex cellular and molecular details of water and electrolyte homeostasis in the kidney. Samples of normal adult human kidney tissue were obtained from surgical specimens, and S1 segments of proximal convoluted tubules were microdissected, placed on collagen-coated culture plate inserts, and cocultured with lethally irradiated 3T3 fibroblasts. Primary cultures of proximal tubule epithelial cells were infected with a replication-defective retroviral construct encoding either wild-type or temperature-sensitive simian virus 40 large T-antigen. Cells forming electrically resistive monolayers were selected and expanded in culture. Three cell lines (HPCT-03-ts, HPCT-05-wt, and HPCT-06-wt) were characterized for proximal tubule phenotype by electron microscopy, electrophysiology, immunofluorescence, Southern hybridization, and reverse transcriptase-polymerase chain reaction. Each of the three formed polarized, resistive epithelial monolayers with apical microvilli, tight junctional complexes, numerous mitochondria, well-developed Golgi complexes, extensive endoplasmic reticulum, convolutions of the basolateral plasma membrane, and a primary cilium. Each exhibited succinate, phosphate, and Na,K- adenosine triphosphatase (ATPase) transport activity, as well as acidic dipeptide- and adenosine triphosphate-regulated mechanisms of ion transport. Transcripts for Na(+)-bicarbonate cotransporter, Na(+)-H(+) exchanger isoform 3, Na,K-ATPase, parathyroid hormone receptor, epidermal growth factor receptor, and vasopressin V2 receptor were identified. Furthermore, immunoreactive sodium phosphate cotransporter type II, vasopressin receptor V1a, and CLIC-1 (NCC27) were also identified. These well-differentiated, transport-competent cell lines demonstrated the growth, immortalization, and differentiation potential of normal, adult, human proximal tubule cells and consequently have wide applicability in cell biology and renal physiology.

Animals↗
PubMed2005

Detection of Ki-ras and p53 mutations by laser capture microdissection/PCR/SSCP.

Efficient detection of somatic mutations is important for the development of clinical molecular diagnostic assays. However, the detection of somatic mutations in tissue is confounded by dilution of the tumor cell population by normal cells. Laser microdissection allows enrichment for tumor-associated genetic alterations to take place at the level of cell selection, eliminating the need to enrich for mutant alleles after amplification. In this chapter a method is described for somatic mutation analysis using cells acquired by laser capture microdissection.

Animals↗
PubMed1977

Open circulation in the human spleen, Dissection scanning electron microscopy of conductive-stained tissue and observation of resin vascular casts.

Human spleen specimens conductive-stained by the tannin-osmium method were microdissected under the scanning electron microscope and it was revealed that arteries open through one or two end-pores (3-4 mu in diameter) into the reticular cell meshes in the Billroth cord and in the perifollicular area. The endothelial cells lining the arterial terminal portion, which may be swollen into a saccular space, are perforated intracellularly. Dumb-bell shaped erythrocytes are seen passing through these side-pores (1-2 mu in diameter). The termination of arteries not in sinuses but in the cordal reticulum was also confirmed by scanning electron microscopy of blood vascular casts of methacrylate resin. These findings evidence that the "open" theory is valid in the human spleen.

Arteries↗
PubMed2001

Expression studies and mutational analysis of the androgen regulated homeobox gene NKX3.1 in benign and malignant prostate epithelium.

PURPOSE: The NKX-3.1gene is an androgen regulated prostate specific homeobox gene that is believed to have a vital role in normal prostate development. In mice the homologue NKx3.1 is exclusively expressed in prostate epithelium. In humans NKX3.1 expression is also restricted to the prostate but to our knowledge the cellular location has not been described. Furthermore, since NKX3.1 maps to chromosomal band 8p21, a region with high loss of heterozygosity in prostate cancer, the gene has been proposed to have tumor suppressor function. In this study we demonstrate that in human prostates NKX3.1 is expressed exclusively in secretory epithelial cells and the level of NKX3.1 expression remains invariant in normal tissue and in tissue showing various grades of prostate cancer. In the 19 cases examined the DNA sequences of the NKX3.1 gene were identical and no mutation was detected. MATERIALS AND METHODS: Frozen tissue from patients who underwent radical prostatectomy was used for this study. For in situ hybridization experiments a 377 bp fragment corresponding to a portion of the 3' untranslated region of the NKX3.1 gene was amplified by polymerase chain reaction and cloned into the pCRII plasmid vector Invitrogen. Antisense or sense [33P] uridine triphosphate labeled RNA probes were generated with SP6 or T7 RNA polymerase and hybridized to the tissue sections. Slides were exposed to photographic emulsion and visualized on autoradiography. Laser capture microdissection was performed to procure pure populations of malignant epithelium. DNA was isolated by digesting samples in proteinase K buffer. Polymerase chain reaction and direct sequencing was performed using standard protocols. RESULTS: In vitro hybridization showed that NKX3.1 expression was restricted to secretory epithelial cells within benign prostate glands. No expression was detected in stroma or infiltrating lymphocytes. NKX3.1 was expressed in all grades of malignant epithelium in all 25 cases examined. Direct sequencing of the coding region of NKX3.1 revealed the wild-type sequence in all 18 microdissected cancers analyzed. CONCLUSIONS: Based on our studies we propose that NKX3.1 gene expression is restricted to benign and malignant secretory epithelium within the prostate but NKX3.1 does not appear to be a classic tumor suppressor gene responsible for prostate cancer initiation. These findings are consistent with the role of NKX3.1 in the development of normal prostate epithelium and maintenance of normal secretory function. Thus, NKX3.1 may represent a useful molecular marker for benign and malignant prostate epithelium.

DNA Mutational Analysis↗
PubMed1996

Complete sequence analysis of a gene (OS-9) ubiquitously expressed in human tissues and amplified in sarcomas.

Amplification and overexpression of genes involved in cellular growth control occur frequently in human tumors. Using a chromosome microdissection-based hybrid-selection strategy, we recently identified two novel genes (OS-9 and OS-4) within 12q13-15, a region frequently amplified in human cancers. We now report further characterization of the full-length OS-9 cDNA sequence consists of 2785 bp from which an open reading frame (ORF) with 667 amino-acid residues was deduced, The predicted polypeptide was water soluble and acidic. We also demonstrate that the OS-9 gene encoded a 2.8-kb mRNA transcribed in all 16 human tissues examined, suggesting that OS-9 is ubiquitously expressed in human tissues. OS-9 was co-amplified with CDK4 in three of five sarcoma tissues. Homology analysis of the amino-acid sequence reveals significant similarities between OS-9 and two ORFs deduced from genomic sequences in Caenorhabditis elegans and Saccharomyces cerevisiae. The region of similarity extended over 200 residues (approximately one-third of each ORF), and eight cysteines were conserved in all three ORFs. These observations suggest that this region comprises a functional domain present in a novel evolutionarily conserved gene family defined by OS-9.

Amino Acid Sequence↗
PubMed2002

Archival fixed histologic and cytologic specimens including stained and unstained materials are amenable to RT-PCR.

Formalin-fixed and paraffin-embedded tissues are increasingly used for analysis of gene expression. However, a large proportion of archival fixed histologic specimens including spare paraffin sections and stained slides, as well as archival cytologic materials, have not been investigated for their suitability for RNA-based analysis. The current study addressed this issue by reverse transcription and polymerase chain reaction (RT-PCR) of the glucose-6-phosphate dehydrogenase (G6PD) transcript in a series of archival histologic and cytologic specimens. The histologic specimens included freshly prepared paraffin sections, spare paraffin sections, hematoxylin and eosin-stained slides, immunostained slides, and decalcified bone marrow trephines. The cytologic specimens comprised cervical smears and various stained and unstained needle aspirates and cell sediments. The G6PD was amplified for five different fragment sizes ranging from 67 bp to 453 bp. It was found that the majority of archival materials were amenable to RT-PCR of small fragments with the overall success rates of 95% and 79% for 67 bp and 151 bp of the G6PD mRNA, respectively. Neither staining nor prolonged storage up to 15 years had major negative effects on RT-PCR, although fine-needle aspirates showed a higher rate of RT-PCR of 242-bp fragment than other types of cytologic specimens and so did Papanicolaou-stained samples than May Grounwald and Giemsa-stained samples. RT-PCR of minute cell populations microdissected from immunostained sections of tonsils and t(11;18)-positive mucosa-associated lymphoid tissue lymphomas showed that as few as 100 cells were adequate for RT-PCR of G6PD and translocation-associated fusion transcript as long as the target fragment was limited to less than 150 bp. Our results demonstrate that archival fixed histologic and cytologic specimens are valuable resources for RT-PCR-based molecular investigations.

Dissection↗
PubMed1992

[Tissue renin content in superficial, midcortical, and juxtamedullary afferent arterioles in rabbits].

Tissue renin content within the kidney decreases from outer to inner cortex. However, it is not known whether this gradient is due to a decrease in the number of afferent arterioles from the outer to inner cortex or the decrease in renin content per afferent arteriole. Furthermore, it is still controversial whether sodium depletion increases or decreases this gradient. According to Taugner et al., sodium depletion induces the extension of renin positive part of afferent arterioles from vascular pole toward interlobular artery. Since the length of extension may differ among superficial, midcortical, and juxtamedullary afferent arterioles, the observed gradient may vary depending on whether the entire afferent arteriole or only the vascular pole is examined. In the present study, we microdissected the entire afferent arterioles from superficial, middle, and juxtamedullary cortex of rabbit kidney, and examined tissue renin content. We studied: 1. whether tissue renin content per afferent arteriole decreases from the outer to inner cortex. 2. whether sodium depletion affects the gradient of tissue renin content within the cortex. In result, we reached the conclusions, as follows: 1. Tissue renin content per afferent arteriole decreases steeply from superficial to midcortical to juxtamedullary afferent arterioles. 2. The absolute difference in renin content among the three types of afferent arterioles becomes greater during sodium depletion. The internephron heterogeneity of tissue renin content may contribute to functional heterogeneity.

Animals↗
PubMed1993

Quantitative measurement of calretinin and beta-actin mRNA [correction of mRNAIN] in rat brain micropunches without prior isolation of RNA.

A microdissection technique for quantitation of neurochemicals in discrete brain nuclei has been applied to quantitative measurement of mRNA. The method permits quantitation of low abundance mRNA from submilligram amounts of tissue (10-500 micrograms protein). Discrete nuclei and other regions of the brain are solubilized in concentrated guanidine thiocyanate solution, mRNA is directly hybridized with riboprobes, and detected with a ribonuclease protection assay. This method eliminates the necessity for RNA isolation from solid tissue. No assumptions regarding RNA recovery are necessary since tissue specimens are solubilized, hybridized and treated with ribonuclease in a single tube. We have determined the mRNA levels of calretinin, a predominantly neuron-specific calcium binding protein in microdissected nuclei and other regions of rat brain. For interassay comparison, measurement of sample protein and beta-actin mRNA permits normalization and quantitation in terms of these internal controls. The quantity of calretinin mRNA ranged from 281 +/- 35 fg/micrograms protein in the thalamic paraventricular nucleus to 2.3 +/- 0.5 fg/micrograms protein for the cerebral cortex. The calretinin/beta-actin ratios ranged from 79.9 +/- 9.3% to 1.3 +/- 0.1%, respectively. The combination of microdissection techniques with a lysate RNase protection assay: (1) establishes this technique as quantitative for detection of high and low abundance mRNAs from microdissected brain specimens; (2) bypasses the inefficiencies and uncertainties associated with isolating RNA; and (3) enables large numbers of determinations from discrete brain nuclei to be analyzed in 2 to 3 days.

Actins↗
PubMed2005

Patterns of K-ras codon 12 and 13 mutations found in pancreatic adenocarcinoma of 30 Chinese patients by microdissection, PCR and direct sequencing.

BACKGROUND AND AIM: To our knowledge there are few reports on the K-ras mutation pattern of pancreatic adenocarcinoma from Chinese mainland patients. We examined surgically resected formalin-fixed, paraffin-embedded primary pancreatic adenocarcinoma tissue blocks for the presence of activating point mutations at codon 12 and 13 of the K-ras gene. METHODS: Mutations were detected through the use of microdissection, polymerase chain reaction (PCR) and direct sequencing. The results were confirmed by reverse sequencing. RESULTS: The combination of microdissection, PCR and direct sequencing techniques resulted in a rapid and sensitive detection of K-ras mutations at codon 12 and 13. Twenty-five (83%) of the 30 pancreatic adenocarcinomas examined harbored K-ras mutation. Among the 25 pancreatic adenocarcinomas, 24 showed K-ras mutation at codon 12 (11 with GGT-GTT, seven with GGT-GAT, four with GGT-CGT, and two with GGT-TGT), and only one showed a GGC-TGC mutation at codon 13. In this study most of K-ras mutations at codon 12 were at the second base (72%, 18/25) with a transition/transversion ratio of 1 : 1.57 (7/11). CONCLUSIONS: The mutation profiles of K-ras at codon 12 in our pancreatic adenocarcinoma samples were significantly different from those of European and Japanese samples.

Adenocarcinoma↗
PubMed2005

Cytogenetic changes and loss of heterozygosity in atypical adenomatous hyperplasia, in carcinoma of the prostate and in non-neoplastic prostate tissue using comparative genomic hybridization and multiplex-PCR.

High grade prostatic intraepithelial neoplasia (PIN) and atypical adenomatous hyperplasia (AAH) are discussed to be precursors of prostate cancer (PC). Unlike high grade PIN the relation between AAH and PC is however unclear. In the present study we analyzed AAH, accompanying prostate carcinomas and carcinomas of the transitional zone after microdissection using comparative genomic hybridization (CGH) and multipelx-PCR with 10 microsatellite polymorphic markers. In every case non-neoplastic prostatic tissue was investigated for the same allelic imbalances. Two AAH showed allelic imbalances in multiplex-PCR. These imbalances did not correlate with the corresponding tumours and furthermore were different to the LOH found in the investigated prostate tumours of the transitional zone. One AAH showed loss on chromosome 22q. We found allelic imbalances in over 50% of non-neoplastic tissue adjacent to prostatic carcinoma. Our findings support the idea that AAH does not seem to be linked closely to PC and should not be considered as an obligate premalignant lesion.

Aged↗
PubMed2006

Molecular determinants in targeted therapy for esophageal adenocarcinoma.

HYPOTHESIS: Cyclooxygenase 2 (COX-2), vascular endothelial growth factor (VEGF), and epidermal growth factor receptor (EGFR) are useful biological determinants in targeted therapy for esophageal adenocarcinoma. DESIGN: Prospective analysis. SETTING: University tertiary referral center. PATIENTS: Sixteen patients with squamous mucosa and normal results of a pH study without mucosal injury (control group), 15 with Barrett esophagus (metaplasia group), and 44 with adenocarcinoma (carcinoma group). INTERVENTIONS: Biopsy specimens were obtained 3 cm above the gastroesophageal junction. Dysplastic tissue was additionally isolated from 9 of the patients in the carcinoma group. After laser-capture microdissection, quantitative real-time polymerase chain reaction was used to measure gene expression across the spectrum of the metaplasia-dysplasia-carcinoma sequence. MAIN OUTCOME MEASURES: Expression of COX-2, VEGF, and EGFR in each patient group. RESULTS: Expression of both COX-2 and VEGF was significantly up-regulated in patients with metaplasia, dysplasia, and cancer compared with controls (P<.01). Expression levels of both were significantly higher in cancer than in the metaplasia group (P<.05) and increased sequentially from metaplasia to dysplasia to cancer. Expression of VEGF was significantly higher in the dysplastic tissue than in nondysplastic Barrett epithelium (P<.05). No change in expression levels of EGFR was seen in the histologic progression to esophageal adenocarcinoma. CONCLUSION: Gene expression data suggest that pharmacologic inhibition of COX-2 and VEGF may be useful adjuncts in targeted therapy for esophageal adenocarcinoma.

Adenocarcinoma↗
PubMed1997

Telomerase activity in reactive and neoplastic lymphoid tissues: infrequent detection of activity in Hodgkin's disease.

We used the recently described sensitive and rapid detection assay called telomeric repeat amplification protocol (TRAP) to detect telomerase activity in lymphoblastoid (n = 5) and lymphoma cell lines (n = 7), hyperplastic lymph nodes (n = 6) and tonsils (n = 5), and tissues involved by non-Hodgkin's lymphoma (NHL) (n = 43) and Hodgkin's disease (HD) (n = 14). Clearly evident telomerase activity was found in all lymphoblastoid and lymphoma cell lines, and in 34 of 43 cases (80%) of NHL. These results were expected because of the proliferative and immortal nature of the cell lines and most malignant cells. However, positive results were obtained with the TRAP assay in all hyperplastic lymph nodes and tonsils, which raises the issue of derepression of telomerase activity during an immune response. Telomerase activity alone therefore does not distinguish malignant lymphoid proliferations from reactive states. Telomerase activity was detected in only 1 of 14 cases (7%) of lymphoid tissues involved by HD. Eight of the 13 negative cases were considered to be interpretable because of the lack (3 of 13 cases) or low level (5 of 13 cases) of telomerase inhibition. The five remaining cases could not be evaluated because of their telomerase inhibitor content. The findings imply either transient or very low levels of telomerase activity in HD or that HD for the greater part is a telomerase-independent neoplasm. Microdissection studies are needed to identify subsets of cells carrying telomerase activity in both reactive and neoplastic lymphoid tissues.

Chromosomes, Human↗