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Klaus Pantel

Publications and source records attributed to Klaus Pantel.

At least 37 records · Page 2Linked to original sources

A pooled analysis of bone marrow micrometastasis in breast cancer.

BACKGROUND: We assessed the prognostic significance of the presence of micrometastasis in the bone marrow at the time of diagnosis of breast cancer by means of a pooled analysis. METHODS: We combined individual patient data from nine studies involving 4703 patients with stage I, II, or III breast cancer. We evaluated patient outcomes over a 10-year follow-up period (median, 5.2 years), using a multivariable piecewise Cox regression model. RESULTS: Micrometastasis was detected in 30.6 percent of the patients. As compared with women without bone marrow micrometastasis, patients with bone marrow micrometastasis had larger tumors and tumors with a higher histologic grade and more often had lymph-node metastases and hormone receptor-negative tumors (P<0.001 for all variables). The presence of micrometastasis was a significant prognostic factor with respect to poor overall survival and breast-cancer-specific survival (univariate mortality ratios, 2.15 and 2.44, respectively; P<0.001 for both outcomes) and poor disease-free survival and distant-disease-free survival during the 10-year observation period (incidence-rate ratios, 2.13 and 2.33, respectively; P<0.001 for both outcomes). In the multivariable analysis, micrometastasis was an independent predictor of a poor outcome. In the univariate subgroup analysis, breast-cancer-specific survival among patients with micrometastasis was significantly shortened (P<0.001 for all comparisons) among those receiving adjuvant endocrine treatment (mortality ratio, 3.22) or cytotoxic therapy (mortality ratio, 2.32) and among patients who had tumors no larger than 2 cm in diameter without lymph-node metastasis and who did not receive systemic adjuvant therapy (mortality ratio, 3.65). CONCLUSIONS: The presence of micrometastasis in the bone marrow at the time of diagnosis of breast cancer is associated with a poor prognosis.

Bone Marrow Neoplasms↗

Circulating tumor cells in breast cancer: correlation to bone marrow micrometastases, heterogeneous response to systemic therapy and low proliferative activity.

PURPOSE: The incidence and biological characteristics of circulating tumor cells in the blood of patients with breast cancer were examined and subgroups were evaluated in the context of systemic treatment and the presence of disseminated tumor cells in bone marrow. EXPERIMENTAL DESIGN: Circulating tumor cells were isolated from the peripheral blood of patients with breast cancer using a gradient system designed for the enrichment of circulating tumor cells (OncoQuick). Circulating tumor cells were identified with the anti-cytokeratin antibody, A45-B/B3. In subsets of patients, expression of the proliferation-associated Ki-67 antigen in circulating tumor cells and the concomitant presence of micrometastases in bone marrow were examined. RESULTS: In patients with primary breast cancer (stage M(0)), circulating tumor cells were detected in 5 of 60 patients (8.3%) after surgery and before initiation of adjuvant chemotherapy; a positive correlation to the presence of disseminated tumor cells in bone marrow was observed (P = 0.030, n = 53). During the course of adjuvant chemotherapy, repeated analysis of 20 M(0) patients revealed the occurrence of circulating tumor cells in 7 of 16 patients that were initially negative. Patients with metastatic disease (stage M(1)) showed circulating tumor cells in 25 of 63 cases (39.7%, P < 0.0001 as compared with M(0) patients), and a positive finding was correlated with elevated concentrations of the serum tumor marker CA15.3 (P = 0.0093). Performing repeated analysis in a subgroup of 25 M(1) patients, circulating tumor cells were found more frequently in patients with progressive disease than in patients with stable disease or remission (87.5% versus 43.8% of patients with circulating tumor cells, respectively; P = 0.047). Independent of the disease-stage, none of the 47 patients examined for the proliferative status of their circulating tumor cells showed coexpression of Ki-67. CONCLUSIONS: Circulating tumor cells seem to be nonproliferating cells that persist during chemotherapy. Circulating tumor cell detection is linked to disease progression and elevated tumor marker concentrations in patients with metastatic breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗

Bi-specific immunomagnetic enrichment of micrometastatic tumour cell clusters from bone marrow of cancer patients.

Metastasis-the spread of tumour cells from a primary lesion to distant organs-is the main cause of cancer-related death, and bone marrow (BM) is a frequent site for the settlement of disseminated tumour cells. Many BM samples harbour isolated tumour cells, whereas tumour cell clusters, as the potential precursors of solid distant metastases, are rarely detected after current enrichment procedures. We have analysed BM samples from 43 patients with carcinomas of the breast, colon and ovaries; 41 of these patients had no clinical signs of overt metastases (stage M0). Tumour cells in BM were enriched with immunomagnetic beads coupled to monoclonal antibodies against both EpCAM and HER2/neu. After enrichment, tumour cells were identified by immunostaining with the anti-cytokeratin antibody A45-B/B3. In total, 886 CK-positive cells were detected in 16 (35%) samples after immunomagnetic enrichment as compared to 34 cells in 9 (21%) samples using Ficoll density centrifugation previously used as the standard enrichment technique. Most remarkably, clusters of 2 to 10 CK-positive cells were found in 75% of CK-positive samples enriched by immunobeads, whereas no CK-positive cell clusters were detected after Ficoll enrichment. The method described offers an excellent tool for the enrichment of micrometastatic tumour cell clusters; these clusters may represent the initial stage of development from a single disseminated tumour cell towards an overt metastasis.

Bone Marrow Neoplasms↗

Influence of immunomagnetic enrichment on gene expression of tumor cells.

BACKGROUND: Metastasis is the leading cause of cancer-related death. Bone marrow (BM) is a frequent site for the settlement of disseminated tumor cells which occurs years before overt metastases signal incurability. METHODS: Here we describe a new method to assess the initial stage of metastasis development in cancer patients. By immunomagnetic selection with HER2/neu and EpCAM as catcher antigens single disseminated tumor cells can be enriched from BM samples. To examine whether the immunomagnetic enrichment technique may change gene expression in the selected tumor cells, we performed differential expression profiling with the breast cancer cell lines MCF-7 and BT474 as models. The profiles were performed using 1.2 Cancer Arrays (Clontech) containing 1176 cDNAs that can be grouped into different functional categories, such as signal transduction, cell cycle, adhesion, cytoskeleton plasticity, growth factors and others. RESULTS: The reproducibility of the gene expression profiling between duplicate cDNA-array experiments was assessed by two independent experiments with MCF-7 breast cancer cells. Scatter blot analysis revealed a good reproducibility of the cDNA array analysis (i.e. less than 10% difference in the gene expression between the arrays). Subsequent comparative cDNA-array analyses of immunobead-selected and unselected MCF-7 and BT474 cancer cells indicated that the antibody incubation during the immunomagnetic selection procedure did not considerably alter the gene expression profile. CONCLUSION: The described method offers an excellent tool for the enrichment of micrometastatic tumor cells in BM without largely changing the gene expression pattern of these cells.

Journal Article↗

The persistence of isolated tumor cells in bone marrow from patients with breast carcinoma predicts an increased risk for recurrence.

BACKGROUND: The prognostic significance of isolated tumor cells (ITCs) in bone marrow (BM) from patients with breast carcinoma at the time of their primary diagnosis recently was been confirmed by a large pooled analysis. If the persistence of ITCs after adjuvant therapy confers a similar risk for recurrence, then it would be an indication to consider secondary adjuvant therapy. METHODS: The authors analyzed BM aspirates from 228 patients during recurrence-free follow-up at a median interval +/- standard deviation (SD) of 21.3 +/- 29.1 months after a primary diagnosis of breast carcinoma (pathologic T1 [pT1]-pT2, pN0-pN3, pM0). Carcinoma cells were detected using a standardized immunoassay with monoclonal antibody A45-B/B3 directed against cytokeratin (CK). Patients were followed for a median +/- SD of 49.8 +/- 32.1 months after their primary diagnosis. RESULTS: Persistent ITCs in BM were detected in 12.7% of patients (n=29 patients). Positive BM status was more frequent (15.7%) within the first 21 months after primary diagnosis than after a follow-up > 21 months (9.7%). The Kaplan-Meier estimate for mean recurrence-free survival was 149.7 months (95% confidence interval [95% CI], 139.6-159.8 months) in patients with negative BM status and 86.5 months (95% CI, 65.7-107.4 months; P=0.0003) in patients with positive BM status at the time patients underwent follow-up BM aspiration. Patients who were without evidence of persistent ITCs had a significantly longer overall survival (162.1 months; 95% CI, 152.1-172.0 months) compared with patients who had positive BM status (overall survival, 98.7 months; 95% CI, 79.7-117.9 months; P=0.0008). In multivariate Cox regression analysis that included BM status, tumor size, lymph node status, and histopathologic grade, evidence of ITCs was an independent significant predictor for reduced disease-free survival (relative risk [RR], 4.57; P <0.0001) and overall survival (RR, 5.57; P=0.002). Persistent ITCs had the greatest prognostic relevance when they were detected between 25 months and 42 months after primary diagnosis (RR, 7.68). CONCLUSIONS: Evidence of persistent ITCs in BM from patients with breast carcinoma indicated an increased risk for subsequent recurrence. Prospective trials should investigate the benefit of secondary adjuvant treatment on the basis of BM marrow status.

Bone Marrow↗

Key role of myosin light chain (MLC) kinase-mediated MLC2a phosphorylation in the alpha 1-adrenergic positive inotropic effect in human atrium.

OBJECTIVE: Mechanisms of the positive inotropic response to alpha(1)-adrenergic stimulation in the heart remain poorly understood, but recent evidence in rat papillary muscle suggests an important role of regulatory myosin light chain (MLC2) phosphorylation. This study investigated alpha(1)-adrenergic contractile effects and the role of MLC kinase (MLCK)-dependent phosphorylation of MLC2 in human atrial muscle strips. METHODS: Force measurement was performed on electrically stimulated atrial muscle strips (n=140; 20 hearts) in the presence of the beta-blocker nadolol. MLC2a phosphorylation was determined by 2D-polyacrylamide gel electrophoresis and Western blotting of muscle strips that were immediately freeze-clamped following force measurements. RESULTS: The alpha(1)-agonist phenylephrine (PE; 0.3-100 microM) exerted a concentration-dependent, monophasic, sustained positive inotropic effect (86% above basal) that was accompanied by an 80% increase in MLC2a phosphorylation. Desinhibition of MLC phosphatase by the Rho kinase inhibitor Y-27632 (10 microM) reduced the effect of PE by 16%. The MLCK inhibitor wortmannin (10 microM) completely abolished both the PE-induced increase in force and MLC2a phosphorylation. The structurally unrelated MLCK inhibitor ML-7 (10 microM) had similar effects. Neither Y-27632 nor wortmannin or ML-7 affected beta-adrenergic force stimulation. In contrast to our findings in atrial muscle strips, we observed no increase in MLC2v phosphorylation after PE in human ventricular muscle strips and wortmannin failed to inhibit PE-induced force of contraction. CONCLUSION: alpha(1)-Adrenergic receptors mediate a prominent increase in contractile force in human atria that depends on MLCK activity and is accompanied by an increase in MLC2 phosphorylation.

Adolescent↗

Bone marrow micrometastases and circulating tumor cells: current aspects and future perspectives.

Early tumor cell dissemination at the single-cell level can be revealed in patients with breast cancer by using sensitive immunocytochemical and molecular assays. Recent clinical studies involving more than 4000 breast cancer patients demonstrated that the presence of disseminated tumor cells in bone marrow at primary diagnosis is an independent prognostic factor. In addition, various assays for the detection of circulating tumor cells in the peripheral blood have recently been developed and some studies also suggest a potential clinical relevance of this measure. These findings provide the basis for the potential use of disseminated tumor cells in bone marrow or blood as markers for the early assessment of therapeutic response in prospective clinical trials.

Bone Marrow Neoplasms↗

Expression of extracellular matrix metalloproteases inducer on micrometastatic and primary mammary carcinoma cells.

PURPOSE: EMMPRIN (extracellular matrix metalloprotease inducer) is a glycosylated member of the immunoglobulin superfamily known to stimulate the production of matrix metalloproteases (MMPs) 1, 2, and 3 and MT1-MMP in peritumoral fibroblasts. We here evaluated whether EMMPRIN expression is related to tumor progression in human breast cancer. EXPERIMENTAL DESIGN: An immunohistochemical study using high-density tissue microarrays (n = 2222 breast cancer samples) and EMMPRIN-specific antibodies HIM6 and MEM-M6/1 was performed, and staining results were statistically correlated with various clinicopathological parameters. To analyze the putative association between EMMPRIN expression and bone marrow (BM) micrometastasis, an additional set of 55 breast tumors from patients with or without micrometastatic cells as determined with anti-cytokeratin antibody A45-B/B3 were included in our study. Cytokeratin-positive cells in BM were costained with EMMPRIN-specific antibody 1G6.2. RESULTS: Positive EMMPRIN staining correlated significantly with various histopathological risk factors (higher tumor grade, increased tumor size, negative estrogen receptor status and progesterone receptor status, and higher mitotic index) as well as decreased tumor-specific survival (log-rank, P = 0.0027). In particular, in patients > 50 years (i.e., postmenopausal women), EMMPRIN expression was an independent prognosticator as shown by Cox regression analysis (relative risk = 1.7, 95% confidence interval 1.4-4.3, P = 0.036). An involvement of EMMPRIN in tumor progression was also supported by the fact that it was expressed on approximately 90% of micrometastatic cells in BM. CONCLUSIONS: EMMPRIN expression in primary tumor predicts an unfavorable prognosis in breast cancer, suggesting a crucial role of EMMPRIN in progression of human mammary carcinomas.

Antigens, CD↗

Genomic profiling of viable and proliferative micrometastatic cells from early-stage breast cancer patients.

PURPOSE: Metastases in distant organs are the major cause of death for cancer patients, and bone marrow is a prominent homing organ for early disseminated cancer cells. However, it remains still unclear which of these cells evolve into overt metastases. We therefore established a new approach based on the analysis of viable and proliferating cancer cells by single-cell comparative genomic hybridization. EXPERIMENTAL DESIGN: The bone marrow of early-stage breast tumor patients (pN(0)M(0)) was screened for tumor cells by immunostaining. By applying special short-term culturing, we selected for viable and proliferative tumor cells. The short-term culturing allowed us to evaluate the proliferative potential of micrometastatic cells, which we had previously shown to represent an independent prognostic marker. We assessed genomic changes in single disseminated cancer cells by single-cell comparative genomic hybridization. RESULTS: We found that these viable disseminated cancer cells already had a plethora of copy number changes in their genome. All of these cells showed chromosomal copy number changes with a substantial intercellular heterogeneity and differences to the matching primary tumors. CONCLUSIONS: The established experimental strategy might pave the way for the identification of metastatic stem cells in cancer patients. Our preliminary results support the new concept that early disseminated cancer cells evolve independently from their primary tumor.

Adult↗

Down-regulated expression of cytokeratin 18 promotes progression of human breast cancer.

PURPOSE: Cytokeratins (CKs) have been recognized for >20 years as structural marker proteins specific for epithelial cells. Recent expression profiling analyses indicate, however, that CK down-regulation may occur in breast cancer. EXPERIMENTAL DESIGN: Here we evaluated the expression pattern of CK18 by immunohistochemical analysis of primary breast carcinomas (n = 1458) spotted on a high-density tissue microarray. The findings were correlated to histopathological risk factors and clinical outcome. RESULTS: Down-regulation of CK18 (as compared to normal breast tissue) was observed in 25.4% of the tumors with a lower rate in lobular carcinomas (17.0%) than in ductal carcinomas (25.4%) or other histological entities (32.5%). CK down-regulation was significantly correlated to advanced tumor stage and high grade but not to axillary lymph node status. Kaplan-Meier survival analysis revealed CK18 as a prognostic indicator of overall survival (P = 0.015) and cancer-specific survival (P = 0.005). CONCLUSIONS: Down-regulation of the luminal CK18 is not rare and a clinically relevant event in breast cancer. This finding has important implications for the use of CK18 as epithelial tumor marker. The correlations with clinical follow-up suggest that CK18 might suppress tumor progression.

Aged↗

Prognostic and predictive impact of the HER-2/ neu extracellular domain (ECD) in the serum of patients treated with chemotherapy for metastatic breast cancer.

BACKGROUND: The extracellular domain of the HER-2/neu -receptor (ECD) is shed from the receptor protein and can be detected in serum. However, the clinical implication of HER-2/neu ECD measurement must be further evaluated. METHODS: In patients with metastatic breast cancer participating in a trial on first-line chemotherapy, the association of serum HER-2/neu ECD with progression-free interval, survival, and response was studied. Blood samples of patients receiving epirubicin and either cyclophosphamide (EC) or paclitaxel (ET) were collected before (n = 103) and in addition, after three courses of therapy (n = 46). RESULTS: HER-2/neu ECD levels correlate with HER-2/neu overexpression of corresponding primary tumors determined by immunohistochemistry (antibody CB11, p = 0.018) with an optimized cut-off at 15 ng/mL. Elevated serum levels of HER-2/neu ECD before chemotherapy were correlated with shorter overall survival (p = 0.0097), but not with reduced progression-free survival and response to chemotherapy. In subgroup analyses, patients with elevated pretherapeutic HER-2/neu ECD levels treated with EC showed shorter overall survival (p = 0.0092); no difference was seen in the ET group. With regard to progression-free survival, patients with elevated HER-2/neu ECD levels tended to benefit from ET (p = 0.0341), in patients with low levels no difference was observed between EC and ET. A decrease of HER-2/neu ECD levels after three courses of therapy was associated with response to therapy (p = 0.006). CONCLUSION: In our group of metastatic breast cancer patients, elevated HER-2/neu ECD levels are associated with decreased overall survival. With regard to progression-free survival, particularly patients with high HER-2/neu ECD levels seem to benefit from taxane-containing chemotherapy.

Adult↗

Mode of spread in the early phase of lymphatic metastasis in pancreatic ductal adenocarcinoma: prognostic significance of nodal microinvolvement.

BACKGROUND: The aim of this study was to assess the prognostic significance of nodal microinvolvement as well as the mode of spread in the early phase of lymphatic metastasis in patients with node-negative pancreatic ductal adenocarcinoma. METHODS: Lymph nodes from 48 node-negative patients with R0 resected pancreatic ductal adenocarcinoma were sampled from 3 different compartments: 1) distal hepatoduodenal ligament, 2) superior-anterior compartment, and 3) posterior-inferior. Tissue sections of 148 lymph nodes classified as tumor free by routine histopathology were examined, using a sensitive immunohistochemical assay with the antiepithelial monoclonal antibody Ber-EP4 for tumor cell detection. With regard to histopathologic tumor staging and grading, 26 (54.2%) of the patients were staged as pT1/pT2, 22 (45.8%) as pT3/pT4, while 31 (64.6%) as G1/G2 and 17 (35.4%) patients as G3. Of the 148 "tumor free" lymph nodes, 56 contained Ber-EP4-positive tumor cells. These 56 lymph nodes were from 28 of the 48 patients. The multivariate Cox regression analysis revealed the independent prognostic impact of nodal microinvolvement on relapse-free and overall survival. Analysis by compartment, from which the lymph nodes were collected, revealed that overall survival time (P = 0.006) and time to local recurrence (P = 0.015) depend on the presence of nodal microinvolvement in the superior-anterior compartment. CONCLUSIONS: The influence of occult tumor cell dissemination in lymph nodes of patients with histologically proven pancreatic ductal adenocarcinoma supports the need for further tumor staging through immunohistochemistry. This could be a helpful tool in proper selection of patients for adjuvant chemotherapy.

Biomarkers, Tumor↗

Detection and characterization of circulating microsatellite-DNA in blood of patients with breast cancer.

Increased levels of circulating DNA have been reported in the blood of cancer patients but not healthy individuals. Tumor-specific genomic aberrations, such as loss of heterozygosity (LOH) and microsatellite instability (MSI), can be detected in this free extracellular DNA. Identification of these genetic aberrations may play an important role in cancer diagnosis and prediction of disease progression. Moreover, the genomic regions involved might harbor potential targets for therapies. To evaluate the incidence of microsatellite alterations in circulating DNA, we assessed the blood serum of 34 patients with primary (n = 8) and metastatic (n = 24) breast cancer. Samples were also analyzed for the presence of circulating tumor cells using an immunocytological cytokeratin assay, and the concentration of the tumor marker CA 15-3 was determined. Genomic DNA extracted from serum and normal blood leukocytes, as a control, was amplified by the polymerase chain reaction using markers at 4 microsatellite loci of chromosomes 10q22-23, 16q22-23, 17q11-12, and 17q21. In 17 of 34 cancer patients, tumor-specific alterations were detected in serum samples. In 16 patients, LOH at various loci was observed, whereas MSI was only detected in the serum of one patient. The pattern of LOH was very heterogeneous, and LOH was detected at chromosomal loci 10q22-23, 16q22-23, and 17q11-12 but not 17q21. No correlation was found between the detection of circulating tumor DNA and the presence of circulating tumor cells in the blood or serum concentration of CA 15-3. In conclusion, genomic aberrations on chromosomes 10, 16, and 17 are frequent in the circulating DNA of breast cancer patients. However, circulating tumor DNA does not reflect the presence of tumor cells in blood or the level of tumor-associated protein markers such as CA 15-3. Thus, screening for circulating tumor DNA may provide additional diagnostic information.

Biomarkers, Tumor↗

Comparative evaluation of urokinase-type plasminogen activator receptor expression in primary breast carcinomas and on metastatic tumor cells.

The urokinase-type plasminogen activator receptor (uPAR, CD87) plays a central role in the plasminogen activation cascade, which participates in extracellular matrix degradation, cell migration and invasion. Here we performed a comprehensive immmunohistochemical evaluation of uPAR expression in primary tumor cells, tumor-surrounding fibroblasts, lymph node metastases and micrometastatic cells in bone marrow of patients with breast carcinomas at the time of primary diagnosis. Variable degrees of uPAR staining of tumor cells were observed in 84 of 93 (90%) carcinomas, whereas intratumoral fibroblasts were uPAR-positive in 70 (75%) carcinomas. The fraction of uPAR-positive primary tumor cells but not fibroblasts was positively correlated with the presence of tumor cells in bone marrow (p = 0.037), whereas no correlation with lymph node metastasis was found. Immunophenotyping of bone marrow and lymph node specimens revealed expression of uPAR on metastatic tumor cells in 10 of 13 and 22 of 23 cases, respectively. Direct comparison to the autologous primary tumor cells showed different uPAR staining scores in most patients with evidence for both up- and downregulation of uPAR on metastatic cells. Our results indicate that uPAR plays an active role in breast cancer metastasis and may therefore be a promising target for new biologic therapies.

Breast Neoplasms↗

Detection and clinical implications of early systemic tumor cell dissemination in breast cancer.

Blood-borne distant metastasis is the leading cause of cancer-related death in breast cancer. The onset of this fundamental process can now be assessed in cancer patients using ultrasensitive immunocytochemical and molecular assays able to detect even single metastatic cells. Analyses of bone marrow (BM) samples show that disseminated cells are present in 20-40% of primary breast cancer patients without any clinical or histopathological signs of metastasis. The common homing of circulating breast cancer cells in BM is indicative for systemic tumor cell spread and predictive for growth of overt metastases in relevant organ sites such as bone, lung, or liver. Recent clinical studies involving more than 3000 breast cancer patients demonstrated that the presence of tumor cells in BM at primary diagnosis is an independent prognostic factor for unfavorable clinical outcome. To date, sampling of BM, however, is not a routine procedure in clinical management of breast cancer patients. Therefore, several research groups have developed sensitive assays for detection of circulating tumor cells in peripheral blood. Studies evaluating the clinical relevance of these blood assays are ongoing. Here, we will review the existing tumor cell assays and discuss their current clinical relevance and perspectives for the clinical management of breast cancer patients.

Antigens, Neoplasm↗

Molecular signature associated with bone marrow micrometastasis in human breast cancer.

Metastasis is the leading cause of cancer-related death, and bone marrow (BM) is a prominent metastatic site in solid tumors. Here, we focused on the onset of metastasis, using BM as an indicator organ for micrometastatic tumor cells in breast cancer patients without overt metastases (tumor-node-metastasis stage M(0)). Expression analysis with cDNA arrays showed distinct profiles between primary tumors from BM-positive and BM-negative patients. The differentially expressed genes are involved in extracellular matrix remodeling, adhesion, cytoskeleton plasticity, and signal transduction (in particular RAS and hypoxia-inducible factor 1alpha pathway). The BM signature was mainly characterized by transcriptional repression and different from the expression signature associated with lymphatic metastasis. Thus, BM micrometastasis is a selective process with a specific molecular signature of the primary tumor.

Bone Marrow Neoplasms↗