Biomedical subjects

Helmut Erich Gabbert

Publications and source records attributed to Helmut Erich Gabbert.

15 recordsLinked to original sources

PubMed2006

Successful high-resolution animal positron emission tomography of human Ewing tumours and their metastases in a murine xenograft model.

PURPOSE: As primary osseous metastasis is the main adverse prognostic factor in patients with Ewing tumours, a NOD/scid mouse model for human Ewing tumour metastases has been established to examine the mechanisms of metastasis. The aim of this study was to evaluate the feasibility of diagnostic molecular imaging by small animal PET in this mouse model. METHODS: Human Ewing tumour cells were transplanted into immune-deficient NOD/scid mice via s.c injection (n=17) or i.v. injection (n=17). The animals (mean weight 23.2 g) were studied 2-7 weeks after transplantation using a submillimetre resolution animal PET scanner. To assess glucose utilisation and bone metabolism, mice were scanned after intravenous injection of 9.6 MBq (mean) 2-[(18)F]fluoro-2-deoxy-D: -glucose (FDG) or 9.4 MBq (mean) [(18)F]fluoride. Whole-body PET images were analysed visually and semi-quantitatively [%ID/g, tumour to non-tumour ratio (T/NT)]. Foci of pathological uptake were identified with respect to the physiological organ uptake in corresponding regions. RESULTS: Subcutaneously transplanted Ewing tumours demonstrated a moderately increased glucose uptake (median %ID/g 2.5; median T/NT 2.2). After i.v. transplantation, the pattern of metastasis was similar to that in patients with metastases in lung, bone and soft tissue. These metastases showed an increased FDG uptake (median %ID/g 3.6; median T/NT 2.7). Osseous metastases were additionally visible on [(18)F]fluoride PET by virtue of decreased [(18)F]fluoride uptake (osteolysis; median %ID/g 8.4; median T/NT 0.59). Metastases were confirmed immunohistologically. CONCLUSION: Diagnostic molecular imaging of Ewing tumours and their small metastases in an in vivo NOD/scid mouse model is feasible using a submillimetre resolution PET scanner.

Animals↗

PubMed2006

Methylation of RAS association domain family protein 1A as a biomarker of lung cancer.

BACKGROUND: Promoter hypermethylation is an important mechanism for silencing tumor-suppressor genes in cancer and a promising tool for development of molecular biomarkers. This study aimed to determine the prevalence of RAS association domain family protein 1A (RASSF1A) promoter hypermethylation in bronchial aspirates of patients with suspected lung cancer and to test whether this type of methylation assay could be used as a diagnostic adjunct to conventional cytology. METHODS: Two hundred three bronchial aspirates from patients with suspected lung cancer were analyzed for RASSF1A hypermethylation by using a sensitive quantitative methylation-specific polymerase chain reaction (QMSP). RESULTS: RASSF1A hypermethylation was found in 88% (35 of 40), 28% (31 of 111), and 100% (6 of 6) of bronchial aspirates collected from patients diagnosed with small cell lung cancer, nonsmall cell lung cancer, and combined small cell lung cancer, respectively. No hypermethylation was detected in patients diagnosed with nonneoplastic lung disease (0 of 46). Depending on histologic subtype, up to 82% of cases presenting with a negative histology showed a positive methylation assay. CONCLUSIONS: The QMSP analysis of RASSF1A hypermethylation enabled a highly specific distinction between patients diagnosed with lung cancer and those with nonneoplastic lung disease. These results suggested that a QMSP assay is a promising molecular tool for diagnosis of primary lung cancer.

Adenocarcinoma↗

PubMed2006

Pitfalls in the detection of t(11;22) translocation by fluorescence in situ hybridization and RT-PCR: a single-blinded study.

The t(11;22) translocation is a diagnostic hallmark of various small round-cell tumors. This study correlates the performance of fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR) in the detection of this translocation analyzing paraffin-embedded tissue specimens. As negative control samples, 10 cases of normal colon mucosa and 10 cases of colon carcinoma tissue were analyzed by FISH to determine a valid cutoff value for the diagnosis of a t(11;22) translocation. The mean number of false-positive nuclei differed significantly between disomic and polysomic control group cases (P=0.002). Therefore, the cutoff value was determined considering the pitfall polysomy. The analysis group consisted of 20 cases from the University of Düsseldorf and 10 cases from the University of Bonn. These cases were analyzed using PCR (Düsseldorf) and FISH (Bonn) using a single-blinded approach. Twenty-two cases (73.3%) were concordant in both methods. Five cases (16.7%) were discrepant, showing a positive result in FISH whereas PCR was negative. Three cases (10.0%) were analyzed by FISH, and PCR failed for nonoptimized tissue preparation. In conclusion, the detection of t(11;22) translocation is critically dependent on a thoroughly defined cutoff value for FISH and on appropriate tissue preparation for both methods. We recommend FISH as a sensitive screening tool in the detection of t(11;22) followed by subsequent PCR amplification of the specific chimeric transcript.

Adult↗

PubMed2005

Methylation assay for the diagnosis of lung cancer on bronchial aspirates: a cohort study.

PURPOSE: Recent studies have detected aberrant promoter methylation of adenomatous polyposis coli promoter 1 A (APC), cyclin-dependent kinase inhibitor-2A (p16(INK4a)), retinoic acid receptor beta2, and RAS association domain family protein 1 (RASSF1A) in bronchial aspirates and suggested their use as biomarkers for lung cancer diagnostics. The purpose of this study was to validate these candidate marker genes in a retrospective cohort study. EXPERIMENTAL DESIGN: Bronchial aspirates collected from a cohort comprising 247 patients with suspected lung cancer were investigated retrospectively regarding aberrant promoter methylation using a quantitative methylation-specific real-time PCR (QMSP). RESULTS: Eighty-nine patients were diagnosed with primary lung cancer, 102 had benign lung disease, and 56 showed miscellaneous other conditions. A panel consisting of APC, p16(INK4a), and RASSF1A emerged as useful combination. This panel detected aberrant methylation in bronchial aspirates of 22 of 35 (63%) and 21 of 44 (44%) centrally and peripherally located primary lung cancers, respectively. Bronchial aspirates also showed aberrant methylation in 5 of 7 (71%) patients with a recurrent lung cancer and in 8 of 30 (27%) cases without tumor recurrence. In contrast, only 1 of 102 patients with benign lung disease displayed a (false) positive test result. Rarely, aberrant methylation was found in patients with other malignancies (3 of 16). The QMSP assay correctly confirmed lung cancer in 8 of 12 (67%) cases with an ambiguous cytology. Moreover, it disclosed 9 of 26 (35%) of peripheral tumors lacking simultaneous cytologic or histologic diagnosis of malignancy. CONCLUSIONS: Our findings suggest that the QMSP assay could be applied as a reflex test in cases of suspected lung cancer that defy a definite diagnosis by conventional methods. Thus, the assay could be a useful diagnostic adjunct especially regarding peripheral tumors.

Adenomatous Polyposis Coli Protein↗

PubMed2004

Paclitaxel/Taxol sensitivity in human renal cell carcinoma is not determined by the p53 status.

In this study, we analyzed the role of the p53 status for paclitaxel/Taxol sensitivity in renal cell carcinomas (RCCs) of the clear cell type. Using immunohistochemistry, nuclear p53 accumulation could not be correlated to the paclitaxel/Taxol sensitivity. DNA sequencing detected a p53 gene mutation in two out of eight RCC cell lines, i.e. in exon 8 (cell line clearCa-6), and in exon 9 (cell line clearCa-5). No correlation, however, was found between the p53 status of our RCC cell lines and their paclitaxel/Taxol sensitivity as indicated by the IC50 values. However, paclitaxel-induced growth inhibition in paclitaxel-sensitive RCC cell lines was accompanied by an increase in apoptosis, irrespective of their p53 status. Although CD95 up-regulation was observed in renal cell carcinoma with wild-type p53 upon paclitaxel treatment, paclitaxel-induced apoptosis itself is triggered independently from the CD95 system. In conclusion, the p53 status cannot predict paclitaxel/Taxol sensitivity in RCC cell lines of the clear cell type.

Antineoplastic Agents, Phytogenic↗

PubMed2004

Hypermethylation of tumor suppressor genes (p16INK4A, p14ARF and APC) in adenocarcinomas of the upper gastrointestinal tract.

Aberrant promoter methylation is an important mechanism for gene silencing. In the present study, 50 Barrett's esophagus-associated esophageal adenocarcinomas (ADC), 50 cardiac ADC and 50 gastric ADC were investigated by means of methylation-specific real-time PCR for hypermethylation in the tumor suppressor genes APC, p16(INk4A) and p14(ARF). Additionally, expression of p16(INK4A) protein in the carcinomas was assessed using immunohistochemistry. Marked differences in hypermethylation were found between esophageal, cardiac and gastric ADC in the APC gene (78% vs. 32% vs. 84%) and in the p16(INK4A) gene (54% vs. 36% vs. 10%). Hypermethylation of p14(ARF) was absent from esophageal ADC and present infrequently in cardiac (2%) and gastric ADC (10%). Complete loss of p16(INK4A) protein expression was detectable in 45% of all tumors and was significantly associated with hypermethylation of the p16(INK4A) gene (p<0.0001, chi(2)-test). Our results suggest that hypermethylation of p16(INK4A) and APC are frequent findings in esophageal, cardiac and gastric ADC. Additionally, the data point to a tumor specific methylation pattern in upper gastrointestinal ADC.

Adenocarcinoma↗

PubMed2004

Expression of the tyrosine kinase c-kit is an independent prognostic factor in patients with small cell lung cancer.

In a retrospective analysis of 203 patients with small cell lung cancer (SCLC), we examined the prognostic value of c-kit expression on survival. Expression of c-kit was examined immunohistochemically in formalin-fixed, paraffin-embedded tissue sections. c-kit was observed in 87.7% of SCLC tumors. Using the Kaplan-Meier model, we found that lack of c-kit expression was associated with significantly shorter survival time compared to the presence of c-kit expression (mean survival 151 +/- 27 vs. 358 +/- 49 days, p = 0.0084). Moreover, the proportion of c-kit(+) cells within the tumor was also related to survival time. Patients with tumors in which >75% of cells stained positive for c-kit had a mean overall survival time of 424 (+/-72) compared to 295 (+/-67) days for patients with 25-75% c-kit(+) tumor cells. Patients with tumors containing <25% c-kit(+) cells had the worst survival, with 164 (+/-24) days (p = 0.0033). Further parameters associated with short survival times were low performance status, elevated levels of lactate dehydrogenase and higher stage according to the TNM classification. Multivariate analysis using the Cox regression model showed that the proportion of c-kit(+) cells within the tumor specimen was one of 3 independent prognostic parameters (p = 0.004) for overall survival next to TNM classification (p = 0.001) and performance status (p < 0.001).

Aged↗

PubMed2004

Distinction between intestinal metaplasia in the cardia and in Barrett's esophagus: the role of histology and immunohistochemistry.

Intestinal metaplasia in Barrett's esophagus (BIM) is a precancerous condition, whereas the carcinogenic potential of intestinal metaplasia of the cardia (CIM) is uncertain. Although clinically important, histological distinction between both conditions by endoscopic biopsies is considered problematic. In the present study, 4-mm samples of BIM (n=31) and CIM (n=9) were selected from esophagectomy specimens that had been resected for esophageal cancer. Slides were coded and stained with hematoxylin and eosin (H&E), Alcian blue-periodic acid-Schiff (PAS), cytokeratins (CK) 7 and 20, and CD10, which labels the intestinal brush border. The predictive value of these stains for the recognition of BIM and CIM was evaluated independently by two senior pathologists. With the use of H&E-stained slides exclusively, BIM samples were categorized correctly in 93.5% and 83.9% of cases (pathologists 1 and 2, respectively), and CIM samples, in 100% and 88.9% of cases. Alcian blue-PAS-positive goblet cells were identified by both investigators in all BIM and CIM samples. BIM-typical CK 7 and 20 immunostaining pattern was identified in 90.3%/83.9% of BIM but only in 11.1%/11.1% of CIM. CD10-positive brush border was present in 32.3%/25.8% of BIM and in 88.9%/88.9% of CIM. When HE-stained slides and immunohistologically stained slides were used together for tissue recognition, BIM were categorized correctly in 90.3%/80.6% of cases, and CIM, in 88.9%/88.9% of cases. In conclusion, BIM and CIM can be usually distinguished on the basis of HE sections. CK 7 and CK 20 expression pattern analysis discriminates correctly between BIM and CIM in the majority of cases. CD10-positive intestinal brush border is present in the majority of CIM but only in a minority of BIM. However, immunohistochemical investigations could not improve the diagnostic accuracy of HE histology alone.

Adult↗

PubMed2003

Overexpression of the mitotic checkpoint genes BUB1, BUBR1, and BUB3 in gastric cancer--association with tumour cell proliferation.

The mitotic spindle assembly checkpoint modulates the timing of anaphase initiation in response to improper alignment of chromosomes at the metaphase plate. The BUB gene family encodes proteins which are part of a large multi-protein kinetochore complex and which are believed to be key components of the checkpoint regulatory pathway. Failure of this surveillance system can lead to genomic instability and could be responsible for the increased incidence of aneuploidy in gastric cancer. Since mutations of BUB genes have not been identified in gastric cancer to date, altered BUB expression levels may significantly impair mitotic checkpoint function. To explore this possibility, the expression levels of BUB1, BUBR1, and BUB3 were determined in 43 gastric carcinomas and corresponding normal gastric mucosa by reverse transcription-polymerase chain reaction (RT-PCR). Gene expression levels were compared with histopathological parameters and DNA ploidy, as well as with proliferative activity, measured by Ki-67 mRNA expression. To the authors' knowledge, this is the first study to investigate the expression levels of mitotic checkpoint genes together with DNA ploidy in gastric cancer. BUB1 was overexpressed in 84%, BUBR1 in 68%, and BUB3 in 79% of gastric cancers. This study also revealed that all three genes were simultaneously overexpressed in 61% of the tumours and that there was a statistically significant positive correlation between overexpression of BUB1, BUBR1 or BUB3 and Ki-67 expression (p < 0.001). Eighty-one per cent of the tumours were classified as aneuploid. However, no correlation was found between ploidy and BUB transcript expression levels. These results suggest that inactivation of the mitotic checkpoint genes BUB1, BUBR1, and BUB3 by epigenetic silencing does not seem to play a role in gastric carcinogenesis. The strong correlation of BUB expression level and tumour cell proliferation suggests that BUB overexpression is a proliferation-dependent phenomenon in gastric cancer. However, overexpression due to lack of normal BUB protein function or due to a yet unknown additional BUB function has to be considered.

Adenocarcinoma↗

PubMed2003

The role of p63 and deltaNp63 (p40) protein expression and gene amplification in esophageal carcinogenesis.

p63, a member of the p53 gene family, is known to encode functionally antagonistic protein isoforms. Although transactivating protein isoforms display p53-like functions, deltaNp63 isoforms act toward p53 in a dominant negative way. Using immunohistochemistry, we examined the expression of pan-p63 and deltaNp63 in 50 esophageal squamous cell carcinomas (SCCs) as well as in squamous low-grade intraepithelial neoplasias (S-LGINs; n = 4) and high-grade intraepithelial neoplasias (S-HGINs; n = 18). Additionally, 50 esophageal adenocarcinomas (ADCs) that arose in Barrett's esophagus (BE) as well as adjacent specialized metaplastic epithelium (SE; n = 41), low-grade intraepithelial neoplasias (B-LGINs; n = 27), and high-grade intraepithelial neoplasias (B-HGINs; n = 21) in BE were investigated. Furthermore, p63 gene amplification was determined by fluorescent differential polymerase chain reaction in a subset of 10 SCCs and 10 ADCs. Whereas in normal esophageal epithelium, expression of pan-p63 is invariably restricted to the basal cell layer, in 100% of S-LGINs, 94.4% of S-HGINs, and 88.0% of SCCs, expression of p63 was found in >75% of the cells. Concerning BE, only in a small subset of SEs (7.3%), B-LGINs (14.8%), B-HGINs (14.3%) and ADCs (16.0%) was a weak p63 protein expression (<10% positive cells) detectable, whereas the rest of the samples were completely negative. Expression of deltaNp63 was identical to expression of pan-p63 in the vast majority of samples. p63 gene amplification was found in 2 of 10 (20.0%) investigated SCCs and in 1 of 10 (10.0%) ADCs. In summary, strong expression of p63, especially its deltaNp63 isoforms, is a frequent finding in esophageal precancerous and cancerous squamous lesions, whereas this is not the case in carcinogenesis of BE. p63 gene amplification is an infrequent finding in esophageal SCCs and ADCs and does not correlate with protein overexpression.

Adenocarcinoma↗

PubMed2003

Prognostic implications of CD95 receptor expression in clear cell renal carcinomas.

The CD95 (Apo-1/Fas) receptor-ligand system is a key regulator of apoptosis. Down-regulation of CD95 receptor and up-regulation of CD95 ligand has been reported in a variety of human tumors and is thought to confer a selective survival advantage. To explore the relevance of the CD95 system for tumor progression and prognosis in clear cell renal cell carcinomas (RCCs), we analyzed CD95 receptor and ligand expression in formalin-fixed tissue from 149 clear cell RCCs by immunohistochemistry. CD95 ligand expression could not be detected in nonneoplastic tubule epithelia and in clear cell RCCs. In contrast, CD95 receptor expression was found in the great majority of clear cell RCCs, and no down-regulation of CD95 receptor protein was evident when compared with nonneoplastic tubule epithelia. Although a significant increase (P = 0.004) of CD95 receptor expression was evident from well-differentiated (G1) to poorly differentiated (G3) RCCs, CD95 receptor expression was not correlated with tumor stage or survival of RCC patients. In conclusion, clear cell RCCs differ from other types of human cancer by their failure to down-regulate CD95 receptor expression or up-regulate CD95 ligand expression during tumor progression. These ex vivo observations suggest that down-regulation of CD95 receptor expression may not provide an additional selective growth advantage to RCC cells and thus further confirm our previous in vitro observations on a functional impairment of CD95-mediated apoptosis in RCC.

Adenocarcinoma, Clear Cell↗

PubMed2003

Diminished coronary reserve in patients with biopsy-proven inflammatory infiltrates.

OBJECTIVE: We tested the hypothesis that patients with biopsy-proven inflammatory infiltrates have an impaired vasodilator capacity of the coronary microvasculation. METHODS: In 80 patients with clinically suspected inflammatory heart disease, coronary regulation was assessed with the argon method (1) at rest and maximal coronary flow (V(cor)/V(max)) and (2) at rest and minimal coronary resistance (R(cor)/R(min)) both before and after dipyridamole (0.5 mg/kg body weight) treatment. RESULTS: Compared to patients without evidence of myocardial inflammation in endomyocardial biopsy (n = 51) but similar demographic characteristics, patients with biopsy-proven inflammatory infiltrates (n = 29) showed significantly reduced maximal coronary flow (286 +/- 122 vs. 189 +/- 78 ml/min x 100 g; p = 0.001) and minimal coronary resistance was increased (0.40 +/- 0.17 vs. 0.60 +/- 0.27 mm Hg x min x 100 g/ml(-1), p = 0.001). The coronary reserve in patients with inflammatory infiltrates was markedly reduced (3.5 +/- 1.1 to 2.4 +/- 0.81, p = 0.001). CONCLUSION: Patients with biopsy-proven inflammatory infiltrates have a diminished coronary reserve due to reduced coronary vasodilator capacity. This may be due to the involvement of the intramural coronary vasculature in inflammatory heart disease.

Adult↗

PubMed2002

Histopathology of the gastroesophageal junction: a study on 36 operation specimens.

The entire gastroesophageal junction of 36 patients who had been operated for squamous cell carcinoma of the upper or middle esophagus was examined. Hematoxylin and eosin-stained slides were evaluated by two pathologists for the following histologic details: minimal and maximal length of cardiac mucosa (CM) and oxyntocardiac mucosa (OCM, mixture of cardiac and fundic glands), degree of inflammation in CM and OCM, and presence of intestinal metaplasia or pancreatic metaplasia. Sections of gastric corpus mucosa were evaluated for the presence of gastritis and infection; sections of esophageal squamous epithelium were evaluated for the presence of reflux esophagitis. CM was present in the entire circumference of the gastroesophageal junction in 20 cases, in parts of the circumference in 15 cases, and entirely absent in one case. The maximal length per case ranged between 1 and 15 mm (median 5 mm). OCM was circumferentially present in 22 cases and partially present in 14 cases. The maximal length ranged between 2 and 24 mm (median 7 mm). Locations of CM/OCM over submucosal esophageal glands or squamous epithelium-lined ducts, both indicating a location in the esophagus, were found in eight cases (22%) and in four cases (11%), respectively. In 18 cases (50%) intestinal metaplasia was present in CM/OCM; pancreatic metaplasia was found in 22 cases (61%). A statistically not significant trend for increase of minimal length of CM, OCM, and the sum of both was found in the presence of gastroesophageal reflux disease. Neither the presence of intestinal metaplasia nor of pancreatic metaplasia in CM/OCM was correlated with gastroesophageal reflux disease. In conclusion, the high variability in length, the frequent occurrence of intestinal metaplasia and pancreatic metaplasia, and the frequent extension into the esophagus suggest that CM/OCM is a dynamic structure that probably mirrors the influence of underlying gastroesophageal diseases. Because of the short length and incomplete circumferential extension of CM/OCM, future endoscopic-bioptic investigations will probably have to be based on more extensive sampling of the gastroesophageal junction.

Adult↗

PubMedDate not supplied

C-myc gene amplification in different stages of oesophageal squamous cell carcinoma: prognostic value in relation to treatment modality.

BACKGROUND: The proto-oncogene c-myc is known to be involved in the regulation of proliferation, apoptosis and cell differentiation. MATERIALS AND METHODS: Amplification of c-myc was determined by means of differential PCR in 77 surgically treated stage I or II oesophageal squamous cell carcinomas (SCC) as well as in 43 locally advanced SCC (cT3-4 cN0-1 cM0) treated by radiochemotherapy and facultatively by surgery. The findings were correlated to overall survival and to response to radiochemotherapy. RESULTS: C-myc gene amplification was present in 8 out of 77 surgically treated SCC (10.4%) and in 13 out of 43 multimodally treated SCC (30.2%). Among the surgically treated tumours, the presence of c-myc amplification was correlated with high proliferative activity (p = 0.0399) but not with overall survival. Among the multimodally treated SCC, c-myc amplification tended to be correlated with response to chemotherapy and response to radiochemotherapy (not significant) whereas no impact on overall survival was found. CONCLUSION: Amplification of c-myc is found more frequently in advanced stages of oesophageal SCC than in early stages. C-myc amplification, however, does not influence the overall survival of oesophageal SCC patients treated either by surgery alone or by multimodal therapy.

Adult↗

PubMedDate not supplied

A new method for optimizing multiplex DNA microsatellite analysis in low quality archival specimens.

BACKGROUND: Testing microsatellite instability seems to be a useful tool for the initial screening of putative non-polyposis colorectal cancer (HNPCC), preceding analysis of germ-line mutations of DNA mismatch repair genes. However, diagnosis of microsatellite instability becomes complicated when highly-damaged DNA from formalin-fixed paraffin-embedded tissue specimens has to be investigated. MATERIALS AND METHODS: A new methodical approach was established based on special multiplex PCR regimes (e.g., on touch-up cycling conditions), allowing both sufficient, as well as specific, amplification of the Bethesda reference panel loci with low quality DNA as template. RESULTS: By applying our new method, microsatellite instability could be analyzed successfully in 75 out of 84 investigated tumors (89%), whereas, by using standard PCR protocols, microsatellite analysis failed in 36% of the investigated cases. CONCLUSION: Our new methodical approach should be recommended for the use of archival material since it allows an efficient and accurate amplification of the Bethesda marker fragments and is less dependent on the DNA quality.

Adaptor Proteins, Signal Transducing↗