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15
result(s) for
"Willenbrock, Klaus"
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Interobserver agreement of proliferation index (Ki-67) outperforms mitotic count in pulmonary carcinoids
by
Sinn, Peter
,
Söder, Stephan
,
Willenbrock, Klaus
in
Algorithms
,
Biomarkers, Tumor - analysis
,
Carcinoid Tumor - epidemiology
2013
Evaluation of proliferative activity is a cornerstone in the classification of endocrine tumors; in pulmonary carcinoids, the mitotic count delineates typical carcinoid (TC) from atypical carcinoid (AC). Data on the reproducibility of manual mitotic counting and other methods of proliferation index evaluation in this tumor entity are sparse. Nine experienced pulmonary pathologists evaluated 20 carcinoid tumors for mitotic count (hematoxylin and eosin) and Ki-67 index. In addition, Ki-67 index was automatically evaluated with a software-based algorithm. Results were compared with respect to correlation coefficients (CC) and kappa values for clinically relevant grouping algorithms. Evaluation of mitotic activity resulted in a low interobserver agreement with a median CC of 0.196 and a median kappa of 0.213 for the delineation of TC from AC. The median CC for hotspot (0.658) and overall (0.746) Ki-67 evaluation was considerably higher. However, kappa values for grouped comparisons of overall Ki-67 were only fair (median 0.323). The agreement of manual and automated Ki-67 evaluation was good (median CC 0.851, median kappa 0.805) and was further increased when more than one participant evaluated a given case. Ki-67 staining clearly outperforms mitotic count with respect to interobserver agreement in pulmonary carcinoids, with the latter having an unacceptable low performance status. Manual evaluation of Ki-67 is reliable, and consistency further increases with more than one evaluator per case. Although the prognostic value needs further validation, Ki-67 might perspectively be considered a helpful diagnostic parameter to optimize the separation of TC from AC.
Journal Article
Differences in the Receptor Status between Primary and Recurrent Breast Cancer - The Frequency of and the Reasons for Discordance
2013
Objective: Receptor discordances between primary and recurrent breast cancer have been described for years, but only a few analyses have elucidated the factors that influence receptor changes. Methods: Explorative analyses of prospective data from a breast cancer database of a tertiary breast cancer unit. Results: Recurrent tumours that had expressed oestrogen (ER) and progesterone receptors (PR) and human epidermal growth factor receptor 2 (HER2) as primary tumours were negative for the respective receptor in 22.8, 41.4 and 40.8% of cases. ER, PR and HER2 expression was found in 19.8, 16.7 and 11.5% of recurrent tumours, although no expression had been observed in primary tumours. Receptor discordances in recurrent disease leading to different therapeutic approaches were noted in 126 of 411 patients (30.7%). In patients with tumours expressing primary ER and HER2, independent factors associated with discordance were endocrine therapy and treatment with trastuzumab. Conclusion: High rates of receptor discordance were found. The impact of factors that influence receptor changes is small so that no subgroup of patients with recurrent breast cancer should be excluded from biopsy. Whenever possible, a biopsy should be taken to confirm the diagnosis of a possible relapse as well as the receptor status of patients with breast cancer.
Journal Article
Das unerwartete synchrone Auftreten zweier Tumorentitäten als diagnostische und therapeutische Herausforderung
2022
Laboruntersuchung Die Tumormarker CA 125 und HE4 („human epididymis protein 4“) waren auf 52 IU/ml (Norm < 35) bzw. 156 pmol/l (Norm bis 83) erhöht. Melanome können darüber hinaus auch aus Pigmentzellen von Dermis, Schleimhäuten, Leptomeningen, Uvea, Retina, Cochlea sowie im Gastrointestinaltrakt entstehen [2]. Flanagan, M; Solon, J; Chang, KH; Deady, S; Moran, B; Cahill, R; Shields, C; Mulsow, J. Peritoneal metastases from extra-abdominal cancer—A population-based study.
Journal Article
Nodular lymphoid lesion of the liver with simultaneous focal nodular hyperplasia and hemangioma: discrimination from primary hepatic MALT-type non-Hodgkin’s lymphoma
by
Willenbrock, Klaus
,
Oeschger, Sabine
,
Kriener, Susanne
in
Adult
,
Antigens, CD20 - analysis
,
B-Lymphocytes - chemistry
2006
Nodular lymphoid lesion (NLL) of the liver is a rare but unique entity and has also been termed reactive lymphoid hyperplasia of the liver. We describe the histological, immunohistochemical and molecular biologic findings of a case with NLL and two other tumors of the liver. The nodular lymphoid mass found in the liver was composed of heterogeneous small lymphocytes forming reactive follicles. Plasma cells, few immunoblasts, centroblasts, few macrophages, epithelioid cells, and giant cells were seen. The lymphoid infiltrate displaced the adjacent hepatic parenchyma. By immunohistochemistry and molecular studies, the lymphocytes were found to be polyclonal. The diagnosis of NLL was made. In addition to NLL, focal nodular hyperplasia and hemangioma were detected. The discrimination of NLL from primary hepatic malignant non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue-type may pose diagnostic difficulties and may require the use of immunohistochemical and molecular techniques. The simultaneous occurrence of NLL with focal nodular hyperplasia and hemangioma in the liver has not been described before.
Journal Article
In angioimmunoblastic T-cell lymphoma, neoplastic T cells may be a minor cell population. A molecular single-cell and immunohistochemical study
by
Willenbrock, Klaus
,
Gaulard, Philippe
,
Renn, Christoph
in
Antigens, CD20 - analysis
,
Biological and medical sciences
,
Cells
2005
The significance of T-cell proliferations in angioimmunoblastic lymphoma (AILD) is still enigmatic. Although classified as a malignant T-cell lymphoma in the World Health Organisation lymphoma classification, some cases of AILD lack dominant T-cell clones. In a previous study, based on single-cell polymerase chain reaction (PCR), we obtained similar results as studies of AILD using Southern blot or conventional PCR: some cases of AILD contained large T-cell clones, and, in other cases, T-cell clones were undetectable. As in single-cell studies, only a limited number of cells could be investigated; thus, we wanted to gain more insight into the amount and distribution of tumour cells. By applying triple immunofluorescent staining with antibodies directed against T-cell receptor Vbeta-family-specific epitopes, we investigated T-cell populations in AILD and their localisation in the tissue in relation to B cells (CD20) and follicular dendritic cells (CD21). In two of five cases investigated, only a minority of the T-cells compartment belonged to the tumour clone. Neoplastic T cells were found throughout the tissue, including areas dominated by B cells.
Journal Article
Nodular lymphoid lesion of the liver with simultaneous focal nodular hyperplasia and hemangioma : discrimination from primary hepatic MALT-type non-Hodgkin's lymphoma
by
OESCHGER, Sabine
,
HANSMANN, Martin-Leo
,
WILLENBROCK, Klaus
in
Biological and medical sciences
,
Hematologic and hematopoietic diseases
,
Investigative techniques, diagnostic techniques (general aspects)
2006
Journal Article
T-Cell Variant of Classical Hodgkin's Lymphoma with Nodal and Cutaneous Manifestations Demonstrated by Single-Cell Polymerase Chain Reaction
by
Willenbrock, Klaus
,
Terui, Tadashi
,
Ichinohasama, Ryo
in
Biological and medical sciences
,
DNA-Binding Proteins - analysis
,
Female
2002
The atypical cells of CD30+ cutaneous lymphoproliferative disorders (CD30CLD) are commonly of T-cell origin and frequently have a similar morphology as Hodgkin or Reed-Sternberg cells of Hodgkin's lymphoma (HL). HL is one of the tumors associated with CD30CLD. Although most studies support a B-cell derivation of the tumor cells in HL, recently a few cases of classical HL with T-cell genotype have been reported. We report a patient who presented with CD30CLD whose lymph nodes showed classical HL of mixed cellularity subtype at presentation. By single-cell PCR, the same clonal gene rearrangements of the T cell receptor-β gene locus could be assigned to the CD30+ and CD15+ cells of both skin and lymph node. In a lymph node biopsy specimen taken in relapse after several courses of chemotherapy, the CD30+ tumor cells were abundant. The T cell–derived tumor cells displayed aberrant expression of the Pax-5 gene in all specimens. A common clonal origin of both CD30CLD and HL of the lymph node in the patient presented here suggests that HL with T-cell genotype exists in association with CD30CLD as well as in sporadic cases and may share clonal origin with the skin tumor.
Journal Article
Analysis of T-Cell Subpopulations in T-Cell Non-Hodgkin’s Lymphoma of Angioimmunoblastic Lymphadenopathy with Dysproteinemia Type by Single Target Gene Amplification of T Cell Receptor- β Gene Rearrangements
by
Willenbrock, Klaus
,
Küppers, Ralf
,
Roers, Axel
in
Amino Acid Sequence
,
Base Sequence
,
Biological and medical sciences
2001
Angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is defined in the current lymphoma classifications as a T-cell non-Hodgkin’s lymphoma. However, in approximately one third of the cases of this lymphoproliferative disease rearrangements of T-cell receptor (TCR) genes indicating clonal expansion of T cells are not detectable. It is currently believed that these cases may represent early stages of a lymphoma with a minor oligoclonal T-cell population. In the present study, 18 lymph nodes with the characteristic histology of AILD were investigated for clonal T-cell receptor gene rearrangements by analysis of DNA extracted from whole tissue sections. Dominant T-cell clones were detected in 12 of these cases. Single CD4
+ and CD8
+ T cells and proliferating Ki67
+ cells of seven cases were micromanipulated from frozen tissue sections. TCRβ gene rearrangements were amplified from these cells by polymerase chain reaction and sequenced. In all informative cases, the clonal gene rearrangements were only detected among CD4
+, and not among CD8
+T cells, indicating that the tumor clones in AILD usually derive from CD4
+ T cells. Minor clonal T-cell populations in those cases in which no clone was found by whole-tissue DNA analysis were not detectable even at single cell resolution. T-cell clones in 4 of 10 cases were found to express similar TCRβ chains, indicating a potential role of (super) antigen triggering in at least some cases of AILD.
Journal Article
Analysis of T-cell subpopulation in T-cell non-Hodgkins lymphoma and angioimmunoblastic lymphadenopathy with dysproteinemia type by single target gene amplification
2001
Angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is defined in the current lymphoma classifications as a T-cell non-Hodgkin's lymphoma. However, in approximately one third of the cases of this lymphoproliferative disease rearrangements of T-cell receptor (TCR) genes indicating clonal expansion of T cells are not detectable. It is currently believed that these cases may represent early stages of a lymphoma with a minor oligoclonal T-cell population. In the present study, 18 lymph nodes with the characteristic histology of AILD were investigated for clonal T-cell receptor gene rearrangements by analysis of DNA extracted from whole tissue sections. Dominant T-cell clones were detected in 12 of these cases. Single CD4(+) and CD8(+) T cells and proliferating Ki67(+) cells of seven cases were micromanipulated from frozen tissue sections. TCRbeta gene rearrangements were amplified from these cells by polymerase chain reaction and sequenced. In all informative cases, the clonal gene rearrangements were only detected among CD4(+), and not among CD8(+) T cells, indicating that the tumor clones in AILD usually derive from CD4(+) T cells. Minor clonal T-cell populations in those cases in which no clone was found by whole-tissue DNA analysis were not detectable even at single cell resolution. T-cell clones in 4 of 10 cases were found to express similar TCRbeta chains, indicating a potential role of (super) antigen triggering in at least some cases of AILD.
Journal Article
CD8 + T Cells in Hodgkin’s Disease Tumor Tissue Are a Polyclonal Population with Limited Clonal Expansion but Little Evidence of Selection by Antigen
by
Willenbrock, Klaus
,
Roers, Axel
,
Rajewsky, Klaus
in
Biological and medical sciences
,
CD8-Positive T-Lymphocytes - cytology
,
CD8-Positive T-Lymphocytes - immunology
2000
A minor component (about 25%) of lymphocytes in Hodgkin’s disease (HD) are CD8
+ T cells. It is unclear whether the presence of these cells reflects an antitumor cytotoxic response. The goal of the present study was to investigate clonal composition and the T cell receptor (TCR) β repertoire of the CD8
+ T cell population in HD. Single CD8
+ cells were micromanipulated from frozen tissue sections of lymph nodes affected by primary HD and subjected to single target amplification of TCRβ gene rearrangements. Sequence analysis of the V region genes revealed the presence of expanded CD8
+ T cell clones in all three cases analyzed. Most of these clonal expansions accounted for less than 10% of the CD8
+ T cell population. In one case, 30% of the CD8
+ T cells belonged to one or two clones. Comparison of V region sequences, however, did not provide evidence that the micromanipulated CD8
+ cells were sampled from a population that was selected for particular antigen specificities. No obvious biases in TCR Vβ and Jβ gene segment usage or CDR3 length distribution were found. Similarities of CDR3 amino acid sequences as found in selected CDR3 structures were rare. These results suggest that, like CD4
+ T cells, CD8
+ T cells may also be recruited into the tumor tissue in an antigen-nonspecific manner.
Journal Article