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Falko Fend

Publications and source records attributed to Falko Fend.

At least 19 recordsLinked to original sources
PubMed2022

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee.

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

Advisory Committees↗
PubMed2006

Germ-line mutations in p27Kip1 cause a multiple endocrine neoplasia syndrome in rats and humans.

MENX is a recessive multiple endocrine neoplasia-like syndrome in the rat. The tumor spectrum in MENX overlaps those of human multiple endocrine neoplasia (MEN) types 1 and 2. We mapped the MenX locus to the distal part of rat chromosome 4, excluding the homologs of the genes responsible for the MEN syndromes (RET and MEN1) and syndromes with an endocrine tumor component (VHL and NF1). We report the fine mapping of the disease locus and the identification of a homozygous frameshift mutation in Cdkn1b, encoding the cyclin-dependent kinase inhibitor p27(Kip1). As a consequence of the mutation, MENX-affected rats show dramatic reduction in p27(Kip1) protein. We have identified a germ-line nonsense mutation in the human CDKN1B gene in a MEN1 mutation-negative patient presenting with pituitary and parathyroid tumors. Expanded pedigree analysis shows that the mutation is associated with the development of an MEN1-like phenotype in multiple generations. Our findings demonstrate that germ-line mutations in p27(Kip1) can predispose to the development of multiple endocrine tumors in both rats and humans.

Amino Acid Sequence↗
PubMed2006

NPM-ALK-dependent expression of the transcription factor CCAAT/enhancer binding protein beta in ALK-positive anaplastic large cell lymphoma.

CCAAT/enhancer binding protein beta (C/EBPbeta) is one of a 6-member family of C/EBPs. These transcription factors are involved in the regulation of various aspects of cellular growth and differentiation. Although C/EBPbeta has important functions in B- and T-cell differentiation, its expression has not been well studied in lymphoid tissues. We, therefore, analyzed its expression by immunohistochemistry and Western blot in normal lymphoid tissues and in 248 well-characterized lymphomas and lymphoma cell lines. Nonneoplastic lymphoid tissues and most B-cell, T-cell, and Hodgkin lymphomas lacked detectable levels of C/EBPbeta. In contrast, most (40 of 45; 88%) cases of ALK-positive anaplastic large cell lymphoma (ALCL) strongly expressed C/EBPbeta. Western blot analysis confirmed C/EBPbeta expression in the ALK-positive ALCLs and demonstrated elevated levels of the LIP isoform, which has been associated with increased proliferation and aggressiveness in carcinomas. Transfection of Ba/F3 and 32D cells with NPM-ALK and a kinase-inhibitable modified NPM-ALK resulted in the induction of C/EBPbeta and demonstrated dependence on NPM-ALK kinase activity. In conclusion, we report the constitutive expression of C/EBPbeta in ALK-positive ALCL and show its relationship to NPM-ALK. We suggest that C/EBPbeta is likely to play an important role in the pathogenesis and unique phenotype of this lymphoma.

Anaplastic Lymphoma Kinase↗
PubMed2006

Constitutive activation of Akt contributes to the pathogenesis and survival of mantle cell lymphoma.

To determine whether the PI3K/Akt signaling pathway is involved in the pathogenesis of mantle cell lymphoma (MCL), we investigated the phosphorylation status of Akt and multiple downstream targets in primary MCL cases and cell lines. Akt was phosphorylated in 12 of 12 aggressive blastoid MCL variants and in 4 of 4 MCL cell lines. In contrast, phosphorylated Akt was present in only 5 of 16 typical MCL, 3 at comparable levels to the blastoid cases, and 2 at low levels. The presence of p-Akt was accompanied by the phosphorylation of p27(kip1), FRKHL-1, MDM2, Bad, mTOR, and p70S6K. Inhibition of the PI3K/Akt pathway in the MCL cell lines abrogated or reduced the phosphorylation of Akt, p27(kip1), FRKHL-1, MDM2, Bad, mTOR, GSK-3beta, IkappaB, and led to cell-cycle arrest and apoptosis. Six MCL cases (5 with activated Akt and 1 with inactive Akt) and 3 of 4 cell lines showed loss of PTEN expression. PIK3CA mutations were not detected. We conclude that constitutive activation of the PI3K/Akt pathway contributes to the pathogenesis of MCL and preferentially occurs in blastoid variants. One possible mechanism of activation is loss of PTEN expression. These data suggest that PI3K/Akt inhibitors may be effective in the treatment of Akt-activated MCL.

Cell Cycle↗
PubMed2006

Differential involvement of TLR2 and TLR4 in host survival during pulmonary infection with Chlamydia pneumoniae.

The relevance of TLR2 and TLR4 for recognizing Chlamydia pneumoniae in vivo during pulmonary infection and to survive the infection was explored. We found that early immune responses triggered by C. pneumoniae partially depended on TLR2, but not on TLR4. The chemokines MIP-2 and MIP-1alpha were not induced, while IL-12p40 levels were higher in TLR2(-/-) mice compared to wild-type mice. Secretion of TNF, keratinocyte-derived chemokine and monocyte chemoattractant protein-1 was attenuated in TLR2(-/-) mice, while IFN-gamma was increased as in wild-type mice. The pulmonary cyto- and chemokine response of TLR2(-/-) x TLR4(d/d) was similar to TLR2(-/-) mice. TLR2(-/-) and TLR2(-/-) x TLR4(d/d) mice also attracted fewer polymorphonuclear neutrophils into the lung, while TLR4(d/d) mice recruited them. Attenuated recruitment of polymorphonuclear neutrophils correlated with reduced weight loss in TLR2(-/-) and TLR2(-/-) x TLR4(d/d) mice and a lower chlamydial burden 3 days post infection. At 9 days post infection, TLR2(-/-) and TLR2(-/-) x TLR4(d/d) mice produced cyto- and chemokines as efficiently as wild-type mice, indicating that the involvement of TLR in inflammation varies over time. All TLR2(-/-) x TLR4(d/d) mice succumbed to the infection, while about 50% of TLR2(-/-) mice died. Taken together, the function of TLR2 and TLR4 is required to survive pulmonary infection with C. pneumoniae.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Early graft failure of small-sized porcine valved conduits in reconstruction of the right ventricular outflow tract.

BACKGROUND: The quest for an alternative to homografts for reconstruction of the right ventricular outflow tract is ongoing. The Shelhigh No-React (NR-4000PA series) treated porcine pulmonic valve conduit (SPVC) was developed as a potential alternative. METHODS: During a 12-month period from May 2004 to May 2005, the SPVC was implanted in 34 patients, of whom 62% were younger than 1 year. Median age at operation was 7 months (range, 5 days to 12 years). Thirteen SPCV conduits size 10, 11 size 12, 8 size 14, and 2 size 16 were initially implanted. Since May 2005, however, we have temporarily abandoned its implantation as we were concerned about a number of early failures. RESULTS: Until November 2005, 1 early and 1 late death have occurred. Both were not conduit related. Fifteen conduits were replaced in 13 patients. Of these, 10 were size 10, 3 size 12, 2 size 14, and none size 16. Mean time to replacement of the SPVC was 313 +/- 116 days. A pseudointimal peel formation and chronic inflammation with foreign-body reaction was found in all explanted conduits at all levels. The maximum of the inflammatory reaction occurred at the valvular level around the porcine tissues, with shrinkage of the valve and hemodynamic compromise. At valvular level, small punctuate calcifications were observed in 2 cases. In 6 patients an acute inflammatory component was observed. At late follow-up (mean follow-up 366 +/- 102 days, 34 patient-years), echocardiography showed a mean graft gradient of 39.8 +/- 29.7 mm Hg, with mild to moderate insufficiency in 4 patients. CONCLUSIONS: Although the No-React treated valve largely resists calcification, pseudointimal peel formation was found in all explanted conduits and led to multilevel conduit stenoses. The small-sized SPVC can not be regarded as an ideal conduit for right ventricular outflow tract reconstruction.

Abnormalities, Multiple↗
PubMed2006

Molecular analysis of light-chain switch and acute lymphoblastic leukemia transformation in two follicular lymphomas: implications for lymphomagenesis.

We observed novel transformations of follicular lymphoma (FL), first, a switch in immunoglobulin (Ig) light chain, and second, transformation of FL to acute lymphoblastic leukemia (ALL). Each set of tumors shared a common clonal origin, as demonstrated by expression of identical, unique CDR IIIH sequences, shared somatic mutations in JH, and identical bcl-2 translocation breakpoints of microdissected ALL cells. Molecular analysis of lambda V-gene expression demonstrated lambda-bearing cells in the original kappa tumor, while expansion of the lambda subclone at relapse occurred after active immunotherapy targeting the Ig receptor. These exceptional cases are compatible with a more contemporary model of lymphomagenesis in which critical events originate from genetic mechanisms which normally occur in germinal center (GC) B cells and challenge the current paradigm of parallel generation of subclones from an early, pre-GC precursor. It is also possible that the outgrowth of these variants was a consequence of immunoselection.

Adult↗
PubMed2006

Bone marrow involvement in follicular lymphoma: comparison of histology and flow cytometry as staging procedures.

Bone marrow (BM) examination is a routine staging procedure in follicular lymphoma (FL). Commonly, both BM histology as well as flow cytometry (FCM) of BM aspirates are performed. In order to compare the diagnostic value of these two techniques, we retrospectively evaluated trephine BM biopsies and listmode data of patients with a confirmed diagnosis of FL, obtained in parallel during a 5-year period. One hundred and thirty nine specimens from 91 patients with FL were eligible for analysis. After joint review, nine cases (6.5%) were reclassified, either in histology (six cases) or FCM (three cases). Seventy nine specimens (57%) showed no infiltration with both methods. Sixty specimens (43%) were scored positive for BM involvement by any of the two techniques. Concordant positive results were obtained in 41 cases (68% of positive BM). False negative results were obtained by FCM in 14 cases (23% of positive BM) and by histology in five cases (8%). Discrepant results between BM histology and FCM are frequent in patients with FL, most likely due to the predominantly paratrabecular infiltration and fibrosis typical for FL. Due to the lower false negative rate, trephine BM biopsy remains crucial for the detection of BM involvement in FL.

Biopsy↗
PubMed2006

Real-time quantitative RT-PCR shows variable, assay-dependent sensitivity to formalin fixation: implications for direct comparison of transcript levels in paraffin-embedded tissues.

Real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) is a versatile tool for precise quantification of gene expression. Formalin-fixed and paraffin-embedded (FFPE) tissue is well suited for qRT-PCR, if RNA extraction is optimized and small amplicon sizes are used. However, little is known whether individual assays may show variable sensitivity to fixation. This is of great importance, if a direct comparison of different transcripts is performed within the same sample, such as for mRNA splice variants. We established a cell culture model to test for and quantify differences in performance of individual qRT-PCR assays on FFPE as compared with fresh material, using TaqMan methodology. RNA was isolated from 7 different cell lines either directly or after preparation of a FFPE cell block. RNA from both sources was reverse transcribed and gene expression quantified using 13 different TaqMan assays. All assays allowed highly reproducible target quantification, using both fresh and FFPE-derived cDNA. The 13 assays showed an average Ct difference of 3.2 between fresh and FFPE cells, if identical amounts of cDNA were used as template. However, the Ct shifts varied from 1.8 to 5.1 for individual assays, indicating variable resistance to fixation. These Ct shift differences were statistically highly significant in 27/78 (35%) of all possible combinations of assays. Because the Ct shift remained constant for each assay, they could be used for calculation of correction factors which rendered FFPE-derived expression data highly comparable to those obtained from fresh material, and as a consequence among each other. Thus, a standardized assessment of qRT-PCR assay efficiencies in FFPE allows for precise intraindividual comparison of mRNA species, such as splice variants with different biologic functions, in archival tissues.

Biological Specimen Banks↗
PubMed2006

Detection of the activating JAK2 V617F mutation in paraffin-embedded trephine bone marrow biopsies of patients with chronic myeloproliferative diseases.

The discovery of the activating V617F mutation in the JAK2 tyrosine kinase in a high proportion of patients with Ph- chronic myeloproliferative diseases (CMPD) represents a diagnostic breakthrough for these disorders. Trephine bone marrow biopsy is an essential part of the diagnostic workup of CMPD and represents a valuable archival source of DNA. Therefore, we studied 152 paraffin-embedded trephines with CMPD and related disorders for the presence of the V617F mutation, using both allele-specific polymerase chain reaction (PCR) and nested PCR with subsequent digestion with BsaXI. Only 6 of 152 (4%) samples were not evaluable because of poor DNA quality. The V617F mutation was detected in 27 of 28 (96%) cases of polycythemia vera, 17 of 23 (74%) cases of essential thrombocythemia, 28 of 45 (62%) cases of chronic idiopathic myelofibrosis, six of eight (75%) cases of CMPD unclassified, and two of four (50%) cases of myelodysplastic/myeloproliferative syndrome. Ph+ chronic myelogenous leukemia (four cases), reactive (secondary) erythrocytosis (14 cases), and thrombocytosis (one case) as well as normal controls (19 cases) all lacked the V617F mutation. Based on results of BsaXI digestion and sequencing, 24 of 54 (44%) evaluable V617F+ cases were considered homozygously mutated. Thus, detection of the V617F JAK2 mutation is feasible in paraffin-embedded trephine biopsies and represents a major advance in the diagnostic evaluation of CMPD.

Adult↗
PubMed2005

Ancillary techniques in bone marrow pathology: molecular diagnostics on bone marrow trephine biopsies.

Pathologic examination of trephine bone marrow (BM) biopsies plays a central role in the diagnosis and staging of haematological neoplasms and other disorders affecting haematopoiesis. Haematopathology has been profoundly influenced by the advent of molecular genetic techniques suitable for paraffin-embedded tissues, and certain applications, such as the determination of B- and T-cell clonality, belong to its standard diagnostic repertoire. Many of these molecular tests can be performed successfully with nucleic acids extracted from BM trephine biopsies, if some technical aspects specific to this template source such as various fixation and decalcification procedures are taken into consideration. The current indications for molecular BM diagnostics range from the confirmation of lymphoma involvement with gene rearrangement analysis, demonstration of tumor-specific translocations in lymphoid and chronic myeloproliferative disorders along to the detection of microorganisms or marrow involvement by soft tissue sarcomas. The availability of quantitative polymerase chain reaction techniques for the investigation of allelic imbalances and gene expression levels in paraffin-embedded material also open new avenues for research and advanced diagnostics. The molecular detection of minimal residual disease in haematological neoplasms, especially in the context of new treatment strategies, will provide future challenges. This article summarizes the current state of the art in molecular diagnostics applied to paraffin-embedded BM biopsies.

Biopsy↗
PubMed2005

Immunohistochemistry in bone marrow pathology: a useful adjunct for morphologic diagnosis.

Pathomorphological examination of trephine biopsies of the bone marrow (BM) represents a standard method for the diagnosis and staging of hematologic neoplasms and other disorders involving the BM. The increasing knowledge about the genetic basis and biology of hematologic neoplasms, as well as the recently proposed WHO classification system, provide the framework for an accurate diagnosis. Although conventional morphology remains the gold standard for paraffin-embedded BM trephines, immunohistochemical stainings have become an integral part of the diagnostic workup. Antibodies suitable for paraffin sections are generally applicable to BM trephines, but modifications of staining protocols may be necessary due to the alternative fixatives and decalcification procedures used for BM biopsies. The indications for immunostainings range from confirmation and classification of lymphoma involvement, subclassification of acute leukemias, and estimating blast counts in myelodysplastic and myeloproliferative syndromes to characterization of BM involvement in nonhematologic neoplasms. Although subtyping of NHL in the BM is more difficult from the point of morphology, classification of the entities that frequently involve the BM, especially the small B-cell lymphomas, can easily be achieved with the help of immunohistochemistry. In this review, we try to summarize the current state of the art in BM immunohistochemistry for the diagnosis of hematologic disorders. Moreover, diagnostic algorithms and useful antibody panels are proposed for a rational and cost-effective approach.

Algorithms↗
PubMed2005

Polymorphonuclear neutrophils improve replication of Chlamydia pneumoniae in vivo upon MyD88-dependent attraction.

Chlamydia pneumoniae, an obligate intracellular bacterium, causes pneumonia in humans and mice. In this study, we show that GR1+/CD45+ polymorphonuclear neutrophils (PMN) surprisingly increase the bacterial load of C. pneumoniae in vivo. Upon intranasal infection of wild-type mice, the lung weight is increased; the cytokines TNF, IL-12p40, and IFN-gamma, as well as the chemokines keratinocyte-derived chemokine, MCP-1, and MIP-2 are secreted; and GR1+/CD45+ PMN are recruited into lungs 3 days postinfection. In contrast, in infected MyD88-deficient mice, which lack a key adaptor molecule in the signaling cascade of TLRs and IL-1R family members, the increase of the lung weight is attenuated, and from the analyzed cyto- and chemokines, only IL-12p40 is detectable. Upon infection, almost no influx of inflammatory cells into lungs of MyD88-deficient mice can be observed. Six days postinfection, however, MyD88-deficient mice were able to produce TNF, IFN-gamma, keratinocyte-derived chemokine, and MCP-1 in amounts similar to wild-type mice, but failed to secrete IL-12p40 and MIP-2. At this time point, the infection increased the lung weight to a level similar to wild-type mice. Curiously, the chlamydial burden in MyD88-deficient mice 3 days postinfection is lower than in wild-type mice, a finding that can be reproduced in wild-type mice by depletion of GR1+ cells. In analyzing how PMN influence the chlamydial burden in vivo, we find that PMN are infected and enhance the replication of C. pneumoniae in epithelial cells. Thus, the lower chlamydial burden in MyD88-deficient mice can be explained by the failure to recruit PMN.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Primary extramedullary plasmacytoma and multiple myeloma: phenotypic differences revealed by immunohistochemical analysis.

Primary extramedullary plasmacytomas are infrequent, typically solitary, plasma cell neoplasms that generally pursue an indolent clinical course but may, rarely, convert to multiple myeloma. Phenotypic differences between these two entities are not well defined. Twenty-eight cases of primary extramedullary plasmacytoma and 26 cases of both medullary (n = 17) and extramedullary (n = 9) multiple myeloma were analysed for the expression of proteins known to play a role in the biology of multiple myeloma. Immunohistochemistry was performed on paraffin wax sections using antibodies against cyclin D1, Bcl-2, Bcl-xL, p27, p21, p53, MIB1, CD20, and CD56. Twenty-three extramedullary plasmacytomas were localized in the upper aerodigestive tract, four in the lymph nodes, and one in the testis. There was a strong male predominance (M : F = 6 : 1). None of the patients died from the disease or progressed to multiple myeloma (mean follow-up 50 months). Nine patients developed local relapse and one patient's tumour evolved into a B-cell non-Hodgkin's lymphoma. In contrast to both intra- and extra-medullary multiple myeloma, extramedullary plasmacytoma showed absence of cyclin D1 (p < 0.001) and infrequent expression of CD56 (p < 0.001). Furthermore, extramedullary plasmacytomas were characterized by weaker staining for Bcl-2 protein and rare overexpression of p21 and p53. In comparison to extramedullary multiple myeloma, extramedullary plasmacytoma showed a more mature morphology and lower proliferation indices (p = 0.008). There was no association between the phenotypic parameters investigated and clinical outcome in extramedullary plasmacytoma. In summary, extramedullary plasmacytoma and multiple myeloma show significant immunophenotypic differences, some of which may be of both diagnostic utility and biological relevance.

Adult↗
PubMed2005

E-cadherin expression in sporadic gastric cancer from Mexico: exon 8 and 9 deletions are infrequent events associated with poor survival.

Aberrant expression and mutation of E-cadherin is frequent in gastric carcinoma (GC) especially of the diffuse type. The frequency of CDH1 (gene encoding E-cadherin) mutation in populations with high incidence of diffuse GC and its prognostic significance is unknown. One hundred seventy-seven gastrectomies from Mexican mestizo patients with intestinal (53), mixed (55), or diffuse (69) GC were included. In addition, 101 endoscopic biopsies from patients with GC not subjected to surgery were analyzed. Immunohistochemistry against wild-type E-cadherin (clone 36) and against 2 mutation-specific antibodies (MSA) recognizing mutant CDH1 lacking exon-8 (del 8) or exon-9 (del 9) were performed. Staining was correlated with histotype, tumor node metastasis stage, and follow-up. Abnormal or absent E-cadherin expression (clone 36) was identified in 84% GC, predominantly in diffuse or mixed tumors (P = 0.004) in advanced stages (P = 0.003). No survival differences at 1 and 2 years were observed among patients showing normal, abnormal, or absent wild type E-cadherin expression. Overall reactivity with the MSA was observed in 10 (5.6%) patients who were treated with surgery. In 140 patients, dead from the disease or alive with the disease, the survival at 1 and 2 years was 37% versus 17% and 14% versus 0 for patients without and with del 8/9 positivity, respectively (log rank P = 0.01). Biopsies from patients with inoperable-GC (101) rendered 5 (4.95%) with del 8 or 9 immunoreactivity. Abnormal E-cadherin expression is frequent in GC. However, exon 8 or 9 deletions were observed in only 5.3% tumors in this series from Mexico, at a lower rate than previously published, but associated with a worse prognosis.

Adolescent↗
PubMed2005

Species identification of mycobacteria in paraffin-embedded tissues: frequent detection of nontuberculous mycobacteria.

Diagnosis of infections caused by mycobacteria, especially nontuberculous mycobacteria still represents a difficult task both in microbiology and pathology. The aim of this study was to determine the frequency of mycobacterial DNA detectable by PCR in formalin-fixed paraffin-embedded tissues showing suspicious granulomatous lesions. A total of 190 archival specimens were analyzed, using a nested PCR protocol, which amplifies a fragment of the mycobacterial 65-kDa heat-shock protein gene. Restriction fragment-length polymorphisms and sequencing were utilized to further analyze the obtained PCR products. Corresponding microbiological culture results were available for 41 cases. We detected mycobacterial DNA in 119 cases (63%), of which 71 (60%) were positive for Mycobacterium tuberculosis complex DNA and 41 (34%) for DNA of nontuberculous mycobacteria. Seven cases (6%) could not be subtyped for technical reasons. The largest group of nontuberculous mycobacteria comprised 29 cases (25% of the 119 positive cases), which were assigned to Mycobacterium fortuitum complex. Mycobacterium avium-intracellulare complex was detected in eight (7%) cases, Mycobacterium gordonae in three (2.5%) and Mycobacterium rhodesiae in a single case (0.8%). All cases of Mycobacterium tuberculosis were unequivocally identified by restriction fragment-length polymorphism analysis. In contrast, sequencing provided a gain of information over restriction fragment-length polymorphism analysis in 37% of the nontuberculous mycobacteria cases (15 of 41). Alignment studies on DNA of nontuberculous mycobacteria showed frequent sequence variations, supporting the existence of sequevars. Comparison of molecular data to available results of microbiological culture assays showed a good concordance of 83%. In conclusion, amplification and sequencing of the mycobacterial 65-kDa heat-shock protein gene is an excellent tool for species identification of mycobacteria, especially nontuberculous mycobacteria, in formalin-fixed paraffin-embedded tissues.

Base Sequence↗