Papers by Ferdinand Hofstaedter
British journal of urology, Jun 1, 1984
Summary— In this prospective study, primary urothelial bladder tumour specimens from 64 patients ... more Summary— In this prospective study, primary urothelial bladder tumour specimens from 64 patients were investigated by means of DNA Feulgen cytophotometry. The patients were followed clinically for at least 7 years. The objective cytophotometric parameters correlated well with the histopathological grading and the cytochemical data were of considerable prognostic value. They were closely correlated with the stage of the tumour, 5‐ and 7‐year survival rates and the probability of tumour recurrence.It is concluded that DNA cytophotometry can serve as a method for the standardisation of histological grading and can give more objective and more detailed prognostic information than conventional histopathology.
British Journal of Urology, 1984
Summary— In this prospective study, primary urothelial bladder tumour specimens from 64 patients ... more Summary— In this prospective study, primary urothelial bladder tumour specimens from 64 patients were investigated by means of DNA Feulgen cytophotometry. The patients were followed clinically for at least 7 years. The objective cytophotometric parameters correlated well with the histopathological grading and the cytochemical data were of considerable prognostic value. They were closely correlated with the stage of the tumour, 5‐ and 7‐year survival rates and the probability of tumour recurrence.It is concluded that DNA cytophotometry can serve as a method for the standardisation of histological grading and can give more objective and more detailed prognostic information than conventional histopathology.
Human Pathology, 2003
Urothelial carcinoma of the renal pelvis and ureter may develop as a manifestation of hereditary ... more Urothelial carcinoma of the renal pelvis and ureter may develop as a manifestation of hereditary nonpolyposis colorectal cancer syndrome (HNPCC), a disorder characterized by mutation or inactivation of a number of DNA mismatch repair genes and detectable as microsatellite instability (MSI). Some urothelial carcinomas display areas of endophytic, or inverted, growth. In this study, urothelial cancers of the upper urinary tract (n ؍ 132) from patients treated at 2 tertiary care centers were studied to identify an association between growth pattern and MSI. Thirty-five neoplasms were microsatellite unstable (26.5%), and MSI was more frequent in papillary lesions than in sessile urothelial cancers (P ؍ .033). The amount of inverted growth was estimated as a percentage of the total tumor. The interobserver and intraobserver concordance in recognizing inverted growth was good, and 65.7% of microsatellite-unstable tumors exhibited at least 20% of an inverted growth component, compared with only 17.5% of microsatellite-stable tumors (P < .0001). In this series, inverted growth predicted MSI with a sensitivity and specificity of .82. Inverted growth in urothelial carcinomas of the upper urinary tract may serve as a marker lesion for MSI and may help identify patients who should be offered testing for HNPCC. HUM PATHOL 34:222-227.
Cytometry Part A, Apr 1, 2010
The prognostic significance of HER2 expression in human breast carcinomas is beyond dispute nowad... more The prognostic significance of HER2 expression in human breast carcinomas is beyond dispute nowadays. The HER family of receptor tyrosine kinases comprises four members (HER1/ErbB1/EGFR, HER2/ErbB2, HER3/ErbB3, and HER4/ErbB4) that act in concert via transactivation and consequently compose a functional signaling unit. Besides HER2 overexpression, coexpression of other HER receptors has substantial impact on course of disease and potential therapeutic benefit. This observation is substantiated by numerous preclinical studies and retrospective studies done on patients with breast cancer. Against this background, the quantification of all HER receptor expressions at the same time would significantly extend the information content revealed by routine diagnosis of breast cancer tissues. Moreover, the knowledge of HER receptor coexpression profiles in primary tumor samples could provide the basis to design and develop highly specific antireceptor treatment strategies. Here, we report on a simultaneous flow cytometric detection of all four HER receptors on carcinoma cells isolated from primary breast cancer tissues and separated from nonepithelial cells by cytokeratin staining. Combined with DNA, i.e. ploidy quantification, the approach resulted in a six-parameter assay that could complement the diagnosis of a variety of diseases in which HER receptor expression has a pivotal impact on the degree of malignancy.
Proceedings of SPIE, Feb 3, 1999
ABSTRACT
Breast Cancer Research, Jul 22, 2009
Introduction HER2 overexpression, or rather HER2 gene amplification, is indicative for Herceptin ... more Introduction HER2 overexpression, or rather HER2 gene amplification, is indicative for Herceptin therapy in both metastatic and pre-metastatic breast cancer patients. Patient's individual sensitivity to Herceptin treatment, however, varies enormously and spans from effectual responsiveness over acquired insensitivity to complete resistance from the outset. Thus no predictive information can be deduced from HER2 determination so that molecular biomarkers indicative for Herceptin sensitivity or resistance need to be identified. Both ErbB receptor-dependent signalling molecules as well as HER2-related ErbB receptor tyrosine kinases, known to mutually interact and to cross-regulate each other are prime candidates to be involved in cellular susceptibility to Herceptin. Methods Using immunohistochemistry and fluorescence in situ hybridisation, we retrospectively investigated primary breast cancer tissues from 48 patients who were under Herceptin treatment. We quantified the gene copy numbers of all HER receptors and evaluated their coexpression profile. Moreover the HER2 phosphorylation state, the ratio of native to truncated HER2, p27(kip1) and PTEN expression were objects of this study. Results Above all markers investigated in this study Kaplan-Meier and Cox regression analysis revealed a significant positive impact of HER4 (co-)expression on overall survival from beginning of antibody therapy. Both HER4 expression and HER4 gene amplification emerged as independent prognostic markers in Herceptin-treated breast cancer patients and responsiveness to Herceptin turned out to be more efficient if tumour cells show HER4 expression. Conclusions Although HER4 is known to potentially exert a tumour cell killing activity and in turn to have a favourable impact in breast cancer patients we demonstrate here the first time that HER4 expression prolongs overall survival in Herceptin-treated patients. Elucidating HER4 receptor function in the context of Herceptin treatment will advance the design of highly efficient receptor targeting. By then we need to extend the analysis of breast cancer by allowing for HER2/HER4 coexpression by which valuable additional prognostic and predictive information might possibly be revealed.
Cytometry, Sep 1, 1994
The epidermal growth factor receptor (EGFR) is considered a tumor-related marker with potential d... more The epidermal growth factor receptor (EGFR) is considered a tumor-related marker with potential diagnostic and prognostic value. In order to assess the sensitivity of flow cytometry to detect EGFR and to quantify receptors objectively, two human bladder carcinoma cell lines with different urothelial differentiation, RT4 and J82, were grown in vitro, and their membrane EGFR content was measured by flow cytometry. Exponential monolayers showed decrease of EGFR content after 20 min pulses with 10 ng/ml EGF in medium, as detected with the antibody EGFR1 in a double staining technique with propidium iodide for DNA evaluation. Further decrease of green fluorescence intensity was seen in cells constantly exposed to EGF. Absolute receptor numbers were determined by Scatchard analysis with radioactive EGF and resulted in relatively low receptor numbers for both cell lines (approximately 3-4 x 10(4) EGFR/cell), as well as one affinity class. These findings could be matched by absolute receptor quantification by flow cytometry, adding beads with defined antigenic sites (Quantum Simply Cellular, Microbead Corporation) to the cell suspension for staining. Our data suggest that flow cytometric EGFR detection and quantitation may be supplied to in vivo tumor samples and that measurements by multiparameter analysis may define subpopulations valuable for tumor diagnosis and judgment on tumor progression.
Cytometry, 2001
Background: Receptors belonging to the epidermal growth factor receptor (EGFR) family transfer ex... more Background: Receptors belonging to the epidermal growth factor receptor (EGFR) family transfer extracellular signals by homotypic and heterotypic receptor interaction and cross-activation. Cell differentiation, death, and proliferation are regulated via these receptor-tyrosine-kinases. However, the initial mechanisms that lead to signal specificity and diversity, which cause a defined cellular response, are incompletely understood. We investigated the recruitment of receptor complexes in two c-erbB2overexpressing breast carcinoma cell lines, SK-BR-3 and BT474, after ligand binding and its effects on intracellular signal transduction and cell cycle regulation. Methods: In order to analyze the coaggregation of receptors on the cell surface induced by specific growth factor treatment, we used the flow cytometric Foerster-type fluorescence resonance energy transfer (FRET) technique. Cell cycle kinetics were monitored flow cytometrically via the anti-BrdU technique and acitivation of intracellular signal cascades was analyzed by Western blotting. Results: After stimulation with EGF BT474, but not SK-BR-3, cells formed EGFR/c-erbB2 receptor complexes. Neither EGF nor heregulin (HRG) induced c-erbB2/c-erbB3 receptor complexes in BT474. However, SK-BR-3 cells exhibited a high amount of c-erbB2/c-erbB3 heterodimers even without growth factor stimulation which could be elevated after prolonged EGF and HRG treatment. In both cell lines, mitogen-activated protein kinase (MAPK) phosphorylation was detectable after short-term and prolonged EGF and HRG treatment. However, only SK-BR-3 cells showed a constitutive activation of both protein kinase B (PKB)/Akt and MAPK signaling pathways. Growth factor treatment caused an amplified PKB/Akt activation in this cell line. The induction of EGFR/c-erbB2 complexes in BT474 was associated with shortening of the G1-phase of the cell cycle. In contrast, the concurrent activation of MAPK and PKB/Akt by EGF treatment led to an inhibition of proliferation in SK-BR-3 and can be attributed to missing EGFR/c-erbB2 heterodimers. HRG was a strong stimulator of proliferation in both cell lines. Conclusions: We show that in the presence of identical amounts of c-erbB2 receptors, the ligand-induced cellular response differs significantly. These differences were mediated by variances in signal transduction, most likely due to different recruitment of heterotypic receptor complexes. Overall, there is strong evidence that c-erbB2 receptor overexpression in breast cancer cells is an insufficient marker to determine cellular response in terms of cell proliferation.
The Journal of Pathology, Feb 24, 2005
The determination of HER2/neu status in breast carcinomas has become essential for the selection ... more The determination of HER2/neu status in breast carcinomas has become essential for the selection of breast cancer patients for Herceptin therapy. Herceptin treatment is used in patients with metastatic breast carcinoma with HER2/neu protein overexpression detected by immunohistochemistry (IHC) or gene amplification analysed by fluorescence in situ hybridization (FISH). A multiparametric fluorescent approach based on the simultaneous detection of HER2/neu gene amplification and protein expression was established to increase the accuracy, and to improve the reproducibility, of HER2/neu diagnostics. Based on four paraffin‐embedded breast cancer cell lines, a combined fluorescent immunostaining (FIHC) and FISH method was developed by using the PathVysion HER2 DNA Probe Kit (VYSIS) and the polyclonal antibody from the HercepTest (DAKO). Diagnostic applicability was documented on 215 formalin‐fixed primary breast carcinomas. Criteria for immunofluorescence quantification were chosen by analogy with the FDA‐approved HercepTest scoring, ranging from 0 to 3+. There was 97.7% concordance between conventional IHC and fluorescence IHC. The FISH data resulting from the multiparametric approach did not differ from conventional FISH. Breast carcinomas with HER2/neu protein overexpression and simultaneous gene amplification were detected with 100% sensitivity. In addition, five of the 215 cases (2.3%) had HER2/neu gene amplification without protein overexpression. The main advantage of this novel approach is that polysomy, aneuploidy, gene amplification, and protein content can be analysed simultaneously in the same cell. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley &amp; Sons, Ltd.
Experimental Cell Research, Apr 1, 2005
Growth factors and Herceptin specifically and differentially modulate cell proliferation of tumor... more Growth factors and Herceptin specifically and differentially modulate cell proliferation of tumor cells. However, the mechanism of action on erbB-receptor level is incompletely understood. We evaluated Herceptin&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s capacity to modulate erbB-receptor activation and interaction on the cell surface level and thereby potentially impair cell proliferation of HER2/neu (c-erbB2) overexpressing breast cancer cells, both in the presence and absence of relevant growth factors. BT474 and SK-BR-3 breast cancer cell lines were treated with Epidermal Growth Factor (EGF), Heregulin, and with Herceptin in different combinations. Kinetics of cell proliferation were evaluated flow cytometrically based on BrdU-labeling. Fluorescence Resonance Energy Transfer, ELISAs and phosphorylation site specific Western Blotting was performed to investigate erbB-receptor interaction and activation. EGF induced EGFR/EGFR and EGFR/c-erbB2 interactions correlate with stimulation of cell proliferation in BT474 cells. Both homo- and heterodimerization are considerably less pronounced in SK-BR-3 cells and heterointeraction is additionally reduced by EGF treatment, causing inhibition of cell proliferation. Heregulin stimulates cell proliferation extensively in both cell lines. Herceptin drives BT474 cells more efficiently into quiescence than it does with SK-BR-3 cells and thereby blocks cell cycle progress. In SK-BR-3 Herceptin treatment causes c-erbB2 phosphorylation of Y877 and Y1248, EGF induces Y877 and Y1112 phosphorylation. The Y1112 phosphorylation site, activated by EGF in SK-BR-3 cell, is bypassed in BT474. In addition the inhibitory capacity of Herceptin on BT474 and SK-BR-3 cell proliferation depends on the presence and absence of growth factors to a various extent. The growth inhibitory effect of Herceptin on c-erbB2 overexpressing breast cancer cells is considerably modulated by EGFR coexpression and consequently EGFR/c-erbB2 homo- and heterointeractions, as well as the presence or absence of growth factors. C-erbB2 overexpression alone is insufficient to predict the impact of growth factors and antibodies on cell proliferation. The optimization and specification of therapeutic approaches based on erbB-receptor targeting requires to account for EGFR coexpression as well as the potential presence of erbB-receptor relevant growth factors.
Histology and histopathology, 2008
In general, it is believed that the extraction of proteins from formalin-fixed paraffin embedded ... more In general, it is believed that the extraction of proteins from formalin-fixed paraffin embedded samples is not feasible. However, recently a new technique was developed, presenting the extraction of non-degraded, full length proteins from formalin fixed tissues, usable for western blotting and protein arrays. In the study presented here, we applied this technique to punch biopsies of formalin fixed tissues embedded in paraffin to reduce heterogeneity of the tissue represented in sections, and to ensure analysing mainly defined cellular material. Successful extraction was achieved even from very small samples (0.7 mm(3)). Additionally, we were able to detect highly glycosylated proteins and protein modification, such as phosphorylation. Interestingly, with this technique it is feasible to extract high quality proteins from 14 year old samples. In summary, the new technique makes a great pool of material now usable for molecular analysis with high throughput tools.
Journal of Cancer, 2011
Background: Little information is available on the long-term outcomes of patients with localised ... more Background: Little information is available on the long-term outcomes of patients with localised prostate cancer. Objective: To examine the long-term survival of patients with localised prostate gland carcinoma T1-T2, N0, M0 (UICC stage I and II) compared to the normal population. Design: Retrospective cohort. Setting: Regensburg, Germany. Participants: Data on 2121 patients with histologically-confirmed, localised prostate cancer diagnosed between 1998 and 2007 were extracted from the cancer registry of the tumour centre in Regensburg, Germany. Measurements: Overall survival rate in the patient cohort was estimated and compared to the expected survival rate of a comparable group in the general population derived from the official life-tables of Germany stratified by age, sex and calendar year. Results: Ten years after diagnosis, patients with stage I and II localised prostate gland carcinoma had an approximately 10% increase in survival compared to the normal male population (Relative Survival = 110.7%, 95%-CI 106.6-114.8%). Limitations: We did not examine the effect of cancer treatment or cancer aggressiveness on the overall survival of patients. We did not assess the incidence of subsequent non-primary cancers in our patient population or how this incidence affects the patients' follow-up care and survival. Conclusions: Patients with stage I+II localised prostate gland carcinoma have improved survival compared with the normal male population. This finding cannot be explained solely by the administration of prostate carcinoma treatments, suggesting that men who participate in PSA screening may have better overall health behaviors and care than men who do not participate in screening. Future research should examine how treatment choice, especially an "active surveillance" approach to care, affects survival in these patients more than ten years after diagnosis.
World Journal of Urology, 2008
Introduction Follow-up after cancer treatment has been focussing on the detection of local recurr... more Introduction Follow-up after cancer treatment has been focussing on the detection of local recurrence or metastatic disease of the primary cancer. Subsequent independent malignancies arising during follow-up have not been considered as relevant. Our study evaluated the risk of independent cancers following the diagnosis of primary urological cancer. Materials and methods From 1990 to 1998 data from 4,119 patients with a minimum follow-up of 5 years were collected. A total of 1,835 patients had primary prostate cancer, 1,269 and 1,015 patients had primary bladder and renal cell cancer, respectively. The most common subsequent malignancies in males were prostate cancer followed by lung and colon cancer. Breast and colon cancer were the most frequently detected subsequent cancers in females. The age correlated comparison of diagnosed and expected cancer in men with primary prostate cancer revealed an increase in relative risk for bladder, kidney and rectal cancer of 3.75, 2.03 and 1.32-fold, respectively. In men with primary bladder cancer the relation for prostate, kidney and lung cancer was 4.05, 2.51 and 2.13-fold, respectively; for females the relation for kidney cancer was 4.55-fold. In men with primary kidney cancer subsequent rectal, prostate and bladder cancer showed a 4.38, 2.91 and 2.48-fold increase, respectively. Conclusion These data suggest an increase in relative risk for subsequent urologic and non-urologic cancer during follow-up. Clinicians involved in oncological follow-up need to be aware of this Wnding. To which degree a follow-up scheme, not solely focussing on the primary urological malignancy could improve survival needs to be evaluated in further studies.
Virchows Archiv, 1995
The aim of the present study was to establish a rapid, non-radioactive screening method for the d... more The aim of the present study was to establish a rapid, non-radioactive screening method for the detection of microsatellite instability (MIN). MIN is the primary characteristic of the mutator phenotype in tumours constituting hereditary non-polyposis colon cancers (HNPCC). We investigated 30 patients suffering from colorectal cancer using a non-radioactive PCR-based technique. MIN was present in 7 of 30 (23%) of the cases. There was a statistically significant correlation between MIN and localization of the tumour. Five of 7 (72%) tumours with MIN but only 4 of 23 (17%) turnouts without MIN were localized in the proximal colon (P<0.01). There was a tendency to higher MIN frequency in turnouts of patients with familial clustering of cancers. However, this was statistically not significant (P>0.05). In addition, no correlation between MIN and tumour grade and stage was found. For the investigations in the present study we used a non-radioactive PCR-based method followed by denaturating polyacrylamide gel electrophoresis and silver staining. This method is highly sensitive and reproducible. Thus, PCR-based analysis using a non-radioactive staining technique represents a comprehensive tool for MIN screening in diagnostic pathology.
Virchows Archiv, 1995
Very recently a new molecular mechanism in the tumorigenesis of colorectal carcinoma has been des... more Very recently a new molecular mechanism in the tumorigenesis of colorectal carcinoma has been described which is closely linked to hereditary non-polyposis colonic cancer (HNPCC). Ubiquitous changes in the length of simple repetitive DNA sequences between constitutional and tumour DNA occur in about 90% of cases of HNPCC and in about 15% of cases of non-familial, sporadic colorectal carcinoma. Such microsatellite instabilities have been shown to be the phenotypical marker of mutations in the human homologues of prokaryotic mismatch repair genes (MutS, MutL, MutH). These data provide crucial new tools in the detection of patients at high risk of developing colon cancer and other HNPCCrelated carcinomas. In addition, these developments provide new insights into a new, presumably primary event in oncogenesis, i.e. the occurrence of mutations in genomic stability genes leading to an increased cellular mutation rate ("mutator phenotype") and thus to cancer.
Pathobiology, 2000
Carcinomas with productive fibrosis are the most common forms of breast cancer. Analysis of tumor... more Carcinomas with productive fibrosis are the most common forms of breast cancer. Analysis of tumor-specific genomic alterations can be compromised by the presence of normal cells, demanding microdissection of small tumor areas to detect loss of heterozygosity (LOH) and microsatellite instability (MSI). The aim of this study was to evaluate the importance of precise laser microdissection for microsatellite analyses and investigation of tumor heterogeneity in breast cancer. 39 primary breast tumor samples were analyzed for MSI and LOH by PCR followed by polyacrylamide gel electrophoresis and silver staining using 15 microsatellite markers. Different tumor areas were processed separately in 30 patients. Both intraductal and invasive breast cancer regions were investigated in 11 patients. The following results were obtained: (1) accurate microdissection revealed MSI in 3 or more of the investigated markers (≧20%) in 33% of the patients, a higher frequency than reported previously; (2) la...
Pathobiology, 2011
The tumor suppressor gene p53 plays an important role in the stress response of the cell and is m... more The tumor suppressor gene p53 plays an important role in the stress response of the cell and is mutated in 50% of all human tumors. The p53 Arg72Pro single-nucleotide polymorphism (SNP) was found to be associated with an increased risk of various malignancies. Biochemical and biological differences between the 2 polymorphic variants of wild-type P53 might lead to distinct susceptibility to HPV- and non-HPV-induced tumors. For prostate cancer, only limited data are available, especially in the Caucasian pop-ulation. Therefore, we determined the distribution of the Arg72Pro SNP in a Caucasian case-control study including 118 prostate cancer patients and 194 male controls without any malignancy using restriction fragment length polymorphism analysis. A subset of 33 tumors was tested for HPV infection, and no HPV DNA was found. Cases and controls showed similar distributions of alleles in the SNP (p = 0.720). Regarding the onset of the disease, patients diagnosed at ≤60 years of age and...
Laboratory Investigation, 2001
Microsatellite alterations can be found in a number of tumors. There are two types of alterations... more Microsatellite alterations can be found in a number of tumors. There are two types of alterations: loss of heterozygosity (LOH), which can be detected in the majority of colorectal cancers (CRC), and microsatellite instability (MSI). MSI occurs in about 15% of CRC with a mutator phenotype and are the hallmark of hereditary nonpolyposis colorectal cancers (HNPCC). Furthermore, MSI can also be detected in other tumors which are part of the HNPCC tumor spectrum (eg, gastric, ovarian, and endometrial carcinomas). Usually, a set of microsatellite markers is amplified by PCR followed by gel or capillary electrophoresis to separate PCR amplicons and by detection of the markers using autoradiography (Thibodeau et al, 1993), silver staining (Schlegel et al, 1996), or fluorescence techniques (Gyapay et al, 1996; Mansfield et al, 1994). We have established a technique to detect MSI by LightCycler PCR and melting point analysis using sequence-specific hybridization probes (HyProbes) labeled with LightCycler dyes, LCRed640 and LCRed705. Amplification of microsatellites by real-time PCR is followed by melting point analysis to display alterations in the length of repetitive sequences, thereby avoiding any electrophoretical separation of amplified DNA. Two mononucleotide markers (BAT25 and BAT26) were tested in 81 formalin-fixed and paraffin-embedded colorectal cancer samples with matched normal tissues from 21 MSI tumors and 60 tumors with microsatellite stability. Amplification and melting point determination of BAT26 and BAT25 was possible in 129/162 (80%) and 123/162 (76%) formalin-fixed and paraffin-embedded tissue samples, respectively. MSI could be detected specifically with both BAT25 and BAT26 markers only in MSI-high tumors (Ն40% MSI rate, determined with microsatellite reference panel, BAT25, BAT26, D5S346, D2S123, D17S250; Boland et al, 1998; Dietmaier et al, 1997). This new technique allows MSI detection within less than a hour and provides a basis for fast, high-throughput MSI analysis.
Journal of Clinical Pathology, 2006
Background and Aims: Chronic lymphocytic leukaemia (CLL) is a frequent non-Hodgkin lymphoma chara... more Background and Aims: Chronic lymphocytic leukaemia (CLL) is a frequent non-Hodgkin lymphoma characterised by a heterogeneous clinical course. Assessment of cell cycle phase kinetics might be important for prediction of clinical behaviour and prognosis. Methods: Distribution of neoplastic cells in CLL within the cell cycle was evaluated by determining the labelling indices (LI, i.e. percentage of positive cells) of markers specific for late G1-phase (cyclin E), S-phase (cyclin A), and G2/M-phase (cyclin B1), and Mcm2, a novel marker of proliferative potential, in a large cohort of patients (n = 79) using tissue microarray (TMA) technology. Utilising a combination of these markers, an algorithm was developed-subtracting the combined LIs of cyclin E, cyclin A and cyclin B1 from the LI of Mcm2-to determine the percentage of tumour cells residing in early G1-phase, which is probably a critical state for the malignant potential of CLL. Results: 27.11% of cells had acquired proliferative potential as indicated by expression of Mcm2. Only a small number of cells were found to be in late G1-phase (7.16%), S-phase (3.31%) or G2/M-phase (0.98%), while 15.66% of cells were considered to be in early G1-phase. Conclusion: Cell cycle phase distribution can easily be assessed by immunohistochemistry in routinely processed paraffin-embedded specimens. A large number of neoplastic cells in CLL have proliferative potential, with a significant sub-population residing in early G1-phase. Estimates of these cells may identify cases likely to exhibit a more aggressive biological behaviour and adverse clinical course.
Clinical Cancer Research, 2007
Purpose: Promoter hypermethylation occurs frequently in tumors and leads to silencing of tumor-re... more Purpose: Promoter hypermethylation occurs frequently in tumors and leads to silencing of tumor-relevant genes like tumor suppressor genes. In a subset of sporadic colorectal cancers (CRC), inactivation of the mismatch repair gene MLH1 due to promoter methylation causes high level of microsatellite instability (MSI-H). MSI-H is also a hallmark of hereditary nonpolyposis colorectal cancer (HNPCC) in which mismatch repair inactivation results from germ-line mutations. For differentiation of sporadic and hereditary MSI-H tumor patients, MLH1 promoter methylation analysis is a promising tool but is not yet used in daily diagnostics because only qualitative techniques without standardization are available. The aim of this study is to establish a reliable and quantitative MLH1 methylation analysis technique and to define valid MLH1 methylation cutoff values for HNPCC diagnostics. Experimental Design: We developed a new real-time PCR–based technique to detect and quantify methylation of bot...
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Papers by Ferdinand Hofstaedter