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H Höfler

Publications and source records attributed to H Höfler.

At least 19 recordsLinked to original sources
PubMed2007

Quantitative protein analysis from formalin-fixed tissues: implications for translational clinical research and nanoscale molecular diagnosis.

Owing to its cross-linking effects, it is currently believed that formalin fixation of routinely processed tissues in the clinic prevents protein extraction and profiling. The aim of our study was to develop a robust, fast, standardized, and easy to use technique for the solubilization of non-degraded, full length, and immunoreactive proteins from formalin-fixed tissues for western blot and protein microarray analysis. Sections of routinely processed formalin-fixed and paraffin-embedded tissues of various origin were analysed. After deparaffination, tissues were manually dissected from the slides and transferred into an optimized protein extraction buffer system. Proteins were solubilized and subsequently analysed by western blot and reverse phase protein microarrays. We succeeded in isolating non-degraded, soluble, and immunoreactive proteins from routinely processed formalin-fixed tissues. We were able to detect membrane, cytoplasmic and nuclear proteins at the expected molecular weight. No differences were found in the protein yield and protein abundances between fresh frozen and formalin-fixed tissues. Using western blots and reverse phase protein microarrays, the receptor tyrosine kinase HER2, an important protein target for antibody based cancer treatment, was reliably measured in formalin-fixed breast cancer biopsy samples when compared with measurement by immunohistochemistry and fluorescence in situ hybridization; remarkably, immunohistochemically equivocal cases (score 2+) can be categorized according to HER2 protein abundance. Our new clinically orientated multiplexed protein measurement system may be generally applicable to determine the relative abundances of known disease-related proteins in small amounts of routinely processed formalin-fixed tissue samples for research and diagnosis. This technique may also be used to identify, characterize, and validate known and new protein markers in a variety of human diseases.

Animals↗
PubMed2006

The prognostic impact of O6-Methylguanine-DNA Methyltransferase (MGMT) promotor hypermethylation in esophageal adenocarcinoma.

Promotor hypermethylation is a common event in human cancer. O6-Methylguanine-DNA Methyltransferase (MGMT) is a gene involved in DNA repair, which is methylated in a variety of cancer types. In colorectal cancer and lung cancer, hypermethylation of MGMT has been correlated with p53 mutation. In the present study, 132 samples of esophageal adenocarcinoma and 58 samples of normal esophageal tissue were investigated for MGMT hypermethylation status by methylation-specific real-time PCR and results were correlated to clinicopathological parameters, patient's survival, p53 mutation and expression of p53 protein and MGMT protein. In the carcinomas, hypermethylation of MGMT was found in 63.6% of cases and loss of MGMT protein expression in 48.5% of cases. Furthermore, MGMT hypermethylation was found in 5.7% of normal esophageal smooth muscle tissue, in 20.0% of esophageal squamous epithelium and in 61.5% of nonneoplastic Barrett's mucosa. In the carcinomas, hypermethylation of the MGMT gene was correlated with loss MGMT protein expression (p < 0.0001) and with high tumor differentiation (p = 0.0079). In contrast, no correlation between MGMT hypermethylation, Lauren's classification, WHO classification, tumor size, gender, age, pT category and pN category, and p53 status was found. Neither MGMT hypermethylation nor loss of MGMT protein expression was correlated with patient's survival. In conclusion, MGMT hypermethylation in esophageal adenocarcinoma is a frequent event that is associated with loss of MGMT protein expression but not with patient's outcome.

Adenocarcinoma↗
PubMed2006

[Experiences of the Bavarian mammography screening program].

The Bavarian Mammography Screening Program started in April 2003. A detailed analysis of the consistency of diagnosis in the evaluation of vacuum-assisted stereotactic or core needle breast biopsies is presented. A total of 32 pathologists participated in a blinded evaluation of the biopsies. Each case was evaluated independently by two participating pathologists. A total of 1,357 cases were reviewed. The histopathological reports of the biopsies made by the two consulting pathologists were compared. The concordance rate of the first and second consulting pathologist was 93% for the B-classification. In general, the level of diagnostic agreement was very high for well defined, benign and malignant lesions. Some of the discrepancies resulted from the incorrect application of the B-classification. Discrepancies in the reports were also due to divergent interpretation of benign and "borderline" lesions. The protocol for the blinded evaluation of breast biopsies in two rounds assured a high level of quality. In conclusion, prerequisites for the success of a mammography screening program are interdisciplinary consensus conferences and audit rounds involving pathologists.

Biopsy, Needle↗
PubMed2006

Argon plasma ablation of gastric inlet patches in the cervical esophagus may alleviate globus sensation: a pilot trial.

BACKGROUND AND STUDY AIMS: Globus sensation and/or sore throat have been associated with both gastroesophageal reflux disease and the presence of a gastric inlet patch. There have been no reports, however, on whether ablation of heterotopic mucosa in the cervical esophagus leads to improvement of chronic globus sensation. PATIENTS AND METHODS: Ten patients with a histologically proved gastric inlet patch who complained of chronic globus sensation and/or sore throat were included in this prospective pilot study. After a thorough assessment, including videofluoroscopy, laryngoscopy, manometry, and 24-hour two-channel pH monitoring, patients underwent argon plasma coagulation (APC) to ablate the heterotopic mucosa. A questionnaire with a visual analog scale ranging from 0 to 10 was used for assessment of globus sensation, sore throat, and other typical or atypical reflux symptoms. Follow-up examinations (including symptom assessment) were performed 4 weeks and 8 weeks after APC therapy. RESULTS: Ablation of the gastric inlet patch resulted in a significant reduction of median symptom scores for globus sensation (from 2.7 to 0) and sore throat (from 2.8 to 0) 8 weeks after therapy ( P < 0.05), but there was no improvement in other reflux-related symptoms. Acid reflux in the distal and proximal esophagus, determined by two-channel pH monitoring, did not change after therapy. CONCLUSIONS: Our preliminary data suggest that ablation of gastric inlet patches by APC can alleviate chronic globus sensation or sore throat. Acid reflux or its treatment is unlikely to influence these results. A randomized and blinded study is warranted.

Adult↗
PubMed2006

Prognostic significance of expression patterns of c-erbB-2, p53, p16INK4A, p27KIP1, cyclin D1 and epidermal growth factor receptor in oesophageal adenocarcinoma: a tissue microarray study.

AIMS: To correlate immunohistochemical expression patterns and prognosis in oesophageal adenocarcinoma. METHODS: The expression of c-erbB-2, p53, p16INK4A, p27KIP1, cyclin D1 and epidermal growth factor receptor (EGFR) was studied in a series of 137 primarily resected oesophageal adenocarcinoma samples. The expression analysis on protein level was performed on routine paraffin wax-embedded material, with immunohistochemical staining of the samples, assembled on a tissue microarray. The results were correlated with clinicopathological features (pT, pN and G) and survival. RESULTS: 22 (16%) tumours showed an overexpression of the c-erbB-2 oncoprotein. Expression of EGFR was observed in 72 (55%) cases, accumulation of p53 in 68 (52%) cases and of cyclin D1 in 102 (77%) cases. Loss of p16INK4A expression was observed in 101 (76%) cases and low expression of p27KIP1 in 91 (71%) cases. Expression of these proteins did not correlate with tumour stage, grade, Lauren's or World Health Organization classification or lymph node status. On univariate survival analysis, more advanced tumour stage (p = 0.002), lymph node involvement (p = 0.003), high tumour grade (p = 0.017) and lack of EGFR expression (p = 0.034) were found to be associated with poorer survival. On multiple regression analysis, only tumour stage (p = 0.03) and lymph node involvement (p = 0.004) were shown to have an association with the survival of the patient. CONCLUSION: The immunohistochemical expression of c-erbB-2 oncoprotein, cylin D1, p16INK4A, p27KIP1, p53 and EGFR in most oesophageal adenocarcinomas suggests their implication in the pathogenesis of this entity. None of the molecular markers assessed, however, was of prognostic value. Identification of any marker superior to or even approaching the prognostic value of conventional histopathological markers (pT and pN) was therefore not possible.

Adenocarcinoma↗
PubMed2006

Clinical proteomics: new trends for protein microarrays.

Protein microarrays are an emerging class of nanotechnology for tracking many different proteins simultaneously. Much progress has been made for applications in basic sciences. Translation of these methods for the treatment of patients, however, is slow, because the realities in the clinic are rarely taken into account, and proteomic changes in cultured cell lines might not fully reflect human diseases due to the lack of the tissue microenvironment. In this review, we summarise current protein microarray approaches that are being developed for profiling tissues and histopathologically defined cell populations from cancer patients. We provide an overview of clinical applications for protein lysate microarrays and discuss the power of this technology for the discovery of disease markers for cancer diagnosis and individualised treatment.

Cell Line, Tumor↗
PubMed2004

Endoscopic measurement of Barrett's esophagus length is unreliable - a prospective comparative biopsy study.

BACKGROUND AND AIMS: Endoscopic assessment of the length and area of Barrett's esophagus (BE) has become crucial in assessing its spontaneous course as well as any effect of pharmacological or endoscopic treatment. Little, however, is known about the extent to which the endoscopic assessment of BE length and area correlates with the histopathological confirmation of BE epithelium. PATIENTS AND METHODS: 75 consecutive patients (mean age 60 years; 58 men, 17 women) were included in a prospective study on the basis of the endoscopic suspicion of BE. BE was endoscopically defined as gastric-type epithelium between the proximal cardiac folds and the Z line, on moderate air insufflation. Stepwise four-quadrant biopsies (4QB) were then taken, beginning at the proximal cardiac folds and then every 2 cm up to the Z line. RESULTS: Among the 75 study patients, BE was histologically verified in 57 cases (group 1) and not confirmed in any of the endoscopic biopsy samples in 18 cases (group 2). In group 1, the mean difference between the endoscopic and histological assessment of BE length was + 1 cm (range 0 - 5 cm); when determining the BE area histologically from 4QB the mean difference to the endoscopic determination was + 36 % (range 0 - 93 %). These differences were independent of the presence and degree of hiatal hernia or the presence of long or short BE. CONCLUSIONS: In the majority of patients, there is only a moderate correlation between the endoscopic and the histological extent of BE. However, we also found a substantial individual variability in endoscopic-histological correlation; therefore studies on the effects of treatment on BE must consider both the endoscopic and histopathological BE lengths.

Adult↗
PubMed2004

The Munich Barrett follow up study: suspicion of Barrett's oesophagus based on either endoscopy or histology only--what is the clinical significance?

BACKGROUND: The incidence of distal oesophageal adenocarcinoma is rising, with chronic reflux and Barrett's oesophagus being considered risk factors. Reliable detection of Barrett's oesophagus during upper endoscopy is therefore mandatory but requires both endoscopy and histology for confirmation. Appropriate management of patients with endoscopic suspicion but negative on histology, or vice versa, or of patients with no endoscopic suspicion but with a biopsy diagnosis of intestinal metaplasia at the gastro-oesophageal junction, has not yet been studied prospectively. PATIENTS AND METHODS: In a prospective multicentre study, 929 patients (51% male, mean age 50 years) referred for upper gastrointestinal endoscopy were included; 59% had reflux symptoms. The endoscopic aspect of the Z line and any suspicion of Barrett's oesophagus were noted, and biopsies were taken in all patients from the Z line (n = 4), gastric cardia (n = 2), and body and antrum (n = 2 each). Biopsies positive for specialised intestinal metaplasia (SIM) were reviewed by a reference pathologist for a final Barrett's oesophagus diagnosis. All patients with endoscopic and/or histological suspicion of Barrett's oesophagus were invited for a follow up endoscopy; the remaining cases (no endoscopic or histological suspicion of Barrett's oesophagus) were followed clinically. RESULTS: Of 235 patients positive for Barrett's oesophagus on endoscopy and/or histology, 63% agreed to undergo repeat endoscopy (mean follow up period 30.5 months). 46% of patients with an endoscopic Barrett's oesophagus diagnosis but no histological confirmation (group A) showed the same distribution, a further 42% did not have Barrett's oesophagus, and 11% had confirmed Barrett's oesophagus on both endoscopy and biopsy on follow up. In the group with a histological Barrett's oesophagus diagnosis but negative on initial endoscopy (group B), follow up showed the same in 26% whereas 46% had no Barrett's oesophagus, and confirmed Barrett's oesophagus (endoscopy plus histology) was diagnosed in 17%. Of the study population, 16 patients had Barrett's oesophagus on initial endoscopy confirmed by histology which remained constant in 70% at follow up (group C). Of the remaining patients without an initial Barrett's oesophagus diagnosis on either endoscopy or histology (group D) and only clinical follow up (mean follow up period 38 months), one confirmed Barrett's oesophagus case was found among 100 patients re-endoscoped outside of the study protocol. However, no single case of dysplasia or cancer of the distal oesophagus was detected in any patient during the study period. CONCLUSIONS: Even in a specialised gastroenterology setting, reproducibility of presumptive endoscopic or histological diagnoses of Barrett's oesophagus at follow up were poor. Only 10-20% of cases with either endoscopic or histological suspicion of Barrett's oesophagus had established Barrett's oesophagus after 2.5 years of follow up. The risk of dysplasia in this population was very low and hence meticulous follow up may not be required.

Adolescent↗
PubMed2004

[Prediction of response to neoadjuvant chemotherapy in Barrett's carcinoma by quantitative gene expression analysis].

The potential of gene expression profiles to predict the response to neoadjuvant chemotherapy in patients with advanced adenocarcinoma of the esophagus was analyzed. Paraffin-embedded endoscopic esophageal tumor biopsies of 38 patients with advanced esophageal adenocarcinoma (Barrett's adenocarcinoma) were included. All patients underwent two cycles of cisplatin and fluorouracil (5-FU) therapy with or without additional paclitaxel (taxol) followed by abdominothoracal esophagectomy. RNA expression levels of 5-FU-metabolism associated genes thymidylate synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), methylenetetrahydrofolate reductase (MTHFR), MAP7, ELF3, as well as of platinum and taxane associated related genes caldesmon, excision cross-complementing genes (ERCC1 and ERCC4) HER2-neu, DNA damage-inducible gene 45 (GADD45) and multidrug resistance genes (MDR1, MRP1) were determined using real-time RT-PCR. Expression levels were correlated with the histopathological response to chemotherapy assessed in surgically resected specimens. Responding patients showed significantly higher pretherapeutic expression levels of MTHFR (p = 0.012), Caldesmon (p = 0.016), MRP1 (p = 0.007) and MDR1 (p = 0.025). In addition, patients with high pretherapeutic MTHFR and MRP1 levels had a survival benefit after surgery (p = 0.013 and p = 0.015, respectively). Additionally, intratumoral heterogeneity of gene expression of selected genes (TP, DPD, MTHFR, HER2-neu, Caldesmon, ERCC4, MRP1) was additionally verified in 9 untreated Barrett's adenocarcinoma by examination of 5 distinct tumor areas and was observed in 12.7% (5.6%-23.5%, CI 95%) of all cases analyzed. Our results indicate that determination of mRNA levels of a few genes may be useful for the prediction of the success of neoadjuvant chemotherapy in individual cancer patients with advanced adenocarcinoma of the esophagus.

Adenocarcinoma↗
PubMed2003

Identification of occult tumor cells in node negative lymph nodes of colorectal cancer patients by cytokeratin 20 gene and protein expression.

BACKGROUND AND AIMS: Evaluation of cytokeratin 20 (CK20) specific quantitative reverse transcriptase polymerase chain reaction (QRT-PCR) and immunohistochemistry (IHC) for detection of occult tumor cells in lymph nodes of 72 patients with colorectal carcinoma (UICC stage I and II). METHODS: Serial sections of formalin-fixed, paraffin-embedded lymph nodes (mean 14.3/case) were used for microdissection, RNA isolation and QRT-PCR and for CK20 IHC using routine protocols. Results of QRT-PCR and IHC were compared and correlated to the CK20 expression pattern of the primary tumors and clinical follow-up. RESULTS: IHC revealed CK20-positive tumor cells in lymph nodes of 14.5% (10/69) and 0% (0/3) cases with a CK20-positive and CK20-negative primary tumor, respectively. CK20 mRNA was detected in the lymph nodes of 36.8% (7/19) cases by QRT-PCR with all 7 cases also expressing CK20 mRNA in the primary tumor. CK20 mRNA (QRT-PCR) and protein (IHC) detection in serial sections did not agree in 25% (5/20) of cases. A trend was seen towards a worse disease course for patients with CK20-positive lymph nodes by IHC (incidence of recurrent disease) and QRT-PCR (disease-free survival, incidence of recurrent disease). CONCLUSION: CK20-specific IHC and QRT-PCR are supportive tools to conventional histology for detection of occult tumor cells in archival tissues, with the restriction that a laborious QRT-PCR procedure is necessary to achieve appropriate specificity. A prognostic value of CK20 IHC or QRT-PCR for stratification of UICC stage I and II patients into those likely to develop recurrent disease was not evident.

Biomarkers, Tumor↗
PubMed2003

[Interlaboratory trial 2000 " Immunohistochemistry" of the German Society for Pathology and the Professional Association of German Pathologists].

Early in 2000 an interlaboratory trial on immunohistochemistry was held in Germany in which 172 pathologists took part. Each pathologist received one H&E stained and five unstained slides of five different tumors to reach a diagnosis based on immunohistochemical stains. Additionally, the diagnosis-independent staining quality was assessed by using a multi-tissue block. Altogether, 828 diagnoses were made, among which 57% (468) were correct. The individual steps of immunohistochemistry (tentative morphological diagnosis, choice of primary antibodies, technical staining quality, conclusions from the diagnosis and rendering a final diagnosis) were assessed independently. Although each of these steps was correlated to the correct final diagnosis, in the multivariate analysis only the tentative diagnosis, choice of primary antibodies and the conclusions drawn from individual stains were independent factors to reach the correct final diagnosis. In the diagnostic part of the interlaboratory trial, the technical quality of the immunostaining was not an independent variable to reach a correct diagnosis. In contrast, the results of the multi-tissue block proved that the immunohistochemical staining quality has to be standardized to reach reproducible results in defining the estrogen receptor expression as a basis for therapeutic decisions.

Coloring Agents↗
PubMed2003

[Carcinoma of the oesophagogastric junction and Barrett's esophagus: an almost clear oncologic model?].

From a clinical and biological point of view, the term "adenocarcinoma of the esophagogastric junction" (AEG) encompasses several distinct tumor entities. The topographic anatomic classification into adenocarcinoma of the distal esophagus (AEG I), true carcinoma of the cardia (AEG II), and subcardiac gastric cancer (AEG III) also reflects differences regarding the pathogenesis of these tumors and is increasingly accepted worldwide. Associated Barrett's esophagus, which usually develops as a consequence of chronic gastroesophageal reflux, can be documented in practically all patients with AEG I tumors and constitutes the most important precancerous lesion. A metaplasia-dysplasia-carcinoma sequence has been confirmed for these tumors. Barrett's esophagus is thus considered a model for studies on carcinogenesis and the prevention of esophageal adenocarcinoma. Its pathogenetic role in AEG II and III tumors must, however, be discussed differently. Our own experience shows that pathogenetic mechanisms similar to those in AEG I tumors may be present in up to 30% of tumors classified as AEG II. The majority of AEG II tumors, however, show morphologic, biologic and pathogenetic similarities with AEG III tumors and proximal gastric cancer.

Adenocarcinoma↗
PubMed2003

Biopsy surveillance is still necessary in patients with Barrett's oesophagus despite new endoscopic imaging techniques.

BACKGROUND AND AIMS: Endoscopic surveillance including stepwise four quadrant biopsies (4QB) is still regarded as the standard approach in patients with Barrett's oesophagus (BO). Several methods such as dye staining with methylene blue (MB) and tissue autofluorescence (AF) have been advocated to reduce the number of biopsies. We assessed their sensitivity and specificity compared with the standard approach-that is, endoscopy with 4QB-in the surveillance of a mixed BO population. PATIENTS AND METHODS: Thirty five consecutive BO patients (mean age 64.9 years; 30 men, five women) were included in the study. AF endoscopy was followed by high resolution video endoscopy (VE) plus tissue staining with 0.5% MB. Biopsies were taken from any suspicious area found on any of the above tests, in addition to 4QB every 2 cm. The results were classified as either positive or negative for the various tests used. Histopathological results were used as the reference standard. RESULTS: In the 35 study patients, a total of 345 biopsies showed low grade dysplasia (LGD) in 88 biopsies, high grade dysplasia (HGD) in 19 biopsies, and carcinoma in 12 biopsies. The sensitivity and specificity rates for AF and MB for the diagnosis of cancer or dysplasia versus BO mucosa without dysplasia were 21%/91% and 37%/91%, respectively. 4QB revealed five cancer/HGD areas and 76 LGD areas not detected by AF, MB, or VE. The additional yield of MB and AF over VE with 4QB concerned only one HGD area (in the vicinity of a cancer) and seven LGD areas. CONCLUSIONS: Due to their low sensitivity, AF and MB are not suitable techniques for reducing the high numbers of routine biopsies needed for finding additional foci of HGD or cancer. Careful endoscopic observation and stepwise four quadrant biopsy therefore still represent the gold standard for surveillance of Barrett's oesophagus.

Adenocarcinoma↗
PubMed2003

[Molecular carcinogenesis of the upper gastrointestinal tract].

Carcinomas of the upper gastrointestinal tract have been intensively studied for decades in order to identify markers for a) design of simple blood tests to detect presence or recurrence of the disease, b) prediction of therapy response, c) identification of molecular targets for novel therapies. These aims have not yet been fully reached by analysing single genes. However, some genes, including E-cadherin that is altered in sporadic and familial cases of gastric cancer and interleukin 1-beta whose polymorphisms together with Helicobacter pylori infection are associated with an increased risk for gastric cancer, may have the potential for clinical use. In this review we summarize current data for the single gene approach and provide an overview for recent results from cDNA microarray studies.

Adenocarcinoma↗