Daniel Re

Whole-body positron emission tomography using 18F-fluorodeoxyglucose for initial staging of patients with Hodgkin's disease

Abstract. An accurate initial staging of patients with Hodgkins disease (HD) is important for the evaluation of clinical stage and risk factors, which are crucial for the choice of an appropriate treatment. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is useful for detecting active tumor tissue in patients with lymphoproliferative diseases and may contribute to conventional staging methods in patients with HD. Twenty-two patients who presented with newly diagnosed HD underwent conventional staging methods including computed tomography (CT) as well as FDG PET. Lesions apparent in FDG PET and CT were correlated to each other. Seventy-seven lesions were observed either in PET or CT or in both. In 48 (62%) lesions PET and CT were both positive. In 20 (26%) sites, PET was positive and CT negative. Of 22 patients (18%) 4 were upstaged due to these positive PET findings, and as a result one patient received a different therapeutic regimen. PET failed to detect nine (12%) CT-positive sites in six patients. Statistically, these data are reflected by a sensitivity for PET and CT of 88% and 74%, respectively. Specificity of both imaging modalities was 100%. PET can contribute valuable information as an additional staging examination and led to an upstaging in some patients with primary HD. However, PET should not be used as the only imaging modality as it failed to detect CT-positive, active tumor regions in some cases.

Part II: Hodgkin's lymphoma—diagnosis and treatment

The outcome of patients with all stages of Hodgkins lymphoma has improved dramatically over the past few decades. This is mainly due to the use of risk-adapted therapies using intensive polychemotherapeutic regimens in combination with other modalities. Patients with early favourable or unfavourable (intermediate) stage disease receive two or four cycles of chemotherapy, respectively, followed by involved-field radiotherapy (20-30Gy). Advanced stage Hodgkins lymphoma is treated more aggressively using six to eight cycles of chemotherapy but the effectiveness of consolidative radiotherapy for patients who show a complete response after chemotherapy alone is still unknown. The main challenge in the near future will be the development of strategies that decrease late morbidity and mortality but retain the same efficacy of current regimens. In this paper we review current diagnostic techniques and management strategies used to treat Hodgkins lymphoma, and the range of new modalities being used to improve long-term outcome and patient quality of life.

Part I: Hodgkin's lymphoma—molecular biology of Hodgkin and Reed-Sternberg cells

Classic Hodgkins lymphoma is characterised by Hodgkin and Reed-Sternberg cells and in most cases are derived from germinal-centre B cells. Despite progress in basic research showing the natural precursor cells of Hodgkins lymphoma, most key questions still remain unanswered. Among these are the basic transforming events, the involvement of oncogenic viruses, the mechanisms enabling Hodgkin and Reed Sternberg cells to resist apoptosis in the germinal centre, and the molecular causes of their characteristic phenotype. Beyond the disclosure of these issues, the detection of changes in gene expression, gene mutations, and chromosomal imbalances specific of Hodgkins lymphoma are central to recent research that may allow one a better understanding of the natural history of this type of lymphoma.

Constitutive Expression of c-FLIP in Hodgkin and Reed-Sternberg Cells

Crosslinking of the transmembrane receptor CD95/Fas leads to activation of a signaling cascade resulting in apoptosis. c-FLIP is a recently described protein that potently inhibits Fas-mediated apoptosis and has been shown to be a key factor in germinal center B cell survival. Because Hodgkin and Reed-Sternberg cells in classical Hodgkins disease (cHD) are also resistant to Fas-mediated apoptosis we studied the role of c-FLIP in classical HD. High levels of c-FLIP protein were identified in two Fas-resistant Hodgkin-derived cell lines. In contrast to other tumor cells, inhibition of protein synthesis by cycloheximide did not lead to down-regulation of c-FLIP protein in these HD cell lines. Furthermore, Fas-mediated apoptosis was only partially restored suggesting that normal regulation of c-FLIP was disrupted. The in vivo relevance of these findings was supported by demonstration of significant c-FLIP expression by immunohistochemistry in 18 of 19 evaluable cases of primary HD. Taken together, c-FLIP is constitutively expressed in HD and may therefore be a major mechanism responsible for Fas-resistance in HD.

Molecular Pathogenesis of Hodgkin's Lymphoma

According to the WHO classification, Hodgkins lymphoma (HL) is subdivided into a classical variant and a nodular lymphocyte predominant variant which are characterized by the presence of Hodgkins and Reed-Sternberg (H-RS) cells or lymphocytic and histiocytic (L&H) cells, respectively. This article reviews genetic characteristics and transcriptional changes of H-RS and L&H cells, including recent knowledge about transforming mechanisms and signaling pathways that contribute to the antiapoptotic phenotype displayed by H-RS and L&H cells. We also discuss major cellular and molecular mediators contributing to the establishment and maintenance of a reactive background in HL-affected tissues. We believe that an in-depth understanding of the pathogenesis of HL will eventually lead to the development of novel biologically based therapeutic strategies in the near future.

Low-dose vemurafenib induces complete remission in a case of hairy-cell leukemia with a V600E mutation.

Hairy-cell leukemia (HCL) is a lymphoproliferative disorder characterized by the presence of CD103-positive circulating B cells, pancytopenia and splenomegaly.[1][1] HCL cases were recently shown to harbor a mutation at codon 600 of BRAF ( V600E ), suggesting that this genetic event represents a key

Elevated pretreatment interleukin-10 serum level is an International Prognostic Score (IPS)-independent risk factor for early treatment failure in advanced stage Hodgkin lymphoma

Early treatment failure is still a clinical challenge despite high cure rates in Hodgkin lymphoma (HL) patients. To identify the biological risk factors predicting early treatment failure, we performed a retrospective case–control study. Forty-seven pretherapeutic serum samples were available from 47 advanced stage HL patients with early treatment failure and from 47 matched controls in complete remission. All patients were treated within German Hodgkin Study Group phase 3 trials. Matching was done according to treatment, stage, age, gender, International Prognostic Score (IPS) and histological subtype. Pretreatment serum levels of 30 cytokines, chemokines and soluble receptors were determined using immunoassays and flow cytometer based cytometric bead arrays. Only interleukin-10 serum levels were significantly associated with early treatment failure after statistical correction for multitesting (paired-sign test, p = 0.0008). In summary, pretherapeutic interleukin-10 levels are associated with early treatment failure within 12 months after the end of treatment in advanced stage HL independently from known clinical factors such as age or IPS.

Immunomagnetic Enrichment and Detection of Micrometastases in Colorectal Cancer: Correlation With Established Clinical Parameters

PURPOSE Micrometastatic disease in bone marrow is of prognostic significance in colorectal cancer patients. However, detection rates of standard immunocytology are relatively low. We used magnetic activated cell sorting (MACS), a highly sensitive method, to increase detection rates and correlated the presence of cytokeratin (CK)-expressing cells with clinical parameters. PATIENTS AND METHODS Bone marrow was obtained from 51 consecutive patients with newly diagnosed colorectal adenocarcinoma who underwent primary surgery and 18 control subjects. International Union Against Cancer (UICC) stage I disease was diagnosed in 11 patients, stage II disease was diagnosed in 14 patients, stage III disease was diagnosed in 12 patients, and stage IV disease was diagnosed in 14 patients. CK-positive cells were enriched and stained with magnetically labeled CAM 5.2 antibodies directed to CK 7 and 8. RESULTS CK-positive cells were found in 33 (65%) patients and were absent in 18 (35%). Four of 11 (36%) patients with UICC stage I disease, nine of 14 (64%) with stage II diease, eight of 12 (67%) with stage III disease, and 12 of 14 (86%) with stage IV disease were CK-positive. Epithelial cells were more frequently found in pT3/4 (72%) than in pT1/2 (36%) tumors (P =.026), but there was no difference for lymph node status. CK-positive patients had a higher chance for elevated carcinoembryonic antigen (85% v 15%, P = NS) and CA 19-9 levels (92% v 8%, P =.019). There were no significant differences in CA 72-4, sex, age, tumor grading, or tumor localization regarding the presence of CK-positive cells. All control subjects were CK-negative. CONCLUSION In searching for micrometastases in colorectal cancer patients, we have achieved high detection rates by using MACS. The presence of these cells correlated significantly with tumor stage, tumor extension, and the tumor marker CA 19-9.

Depsipeptide induces cell death in Hodgkin lymphoma-derived cell lines

A variety of genetic and epigenetic abnormalities were characterized over the last years in Hodgkin and Reed-Sternberg (H-RS) cells of classic Hodgkin Lymphoma (cHL). It was speculated that simultaneous inhibition of multiple signalling pathways might be a promising strategy to target this tumor entity. In the present study we tested the effect of histone deacetylase (HDAC) inhibition using depsipeptide (also known as romidepsin, FK228, FR901228 or NSC-630176) in cHL cell lines in vitro. Molecular mechanisms of toxicity were analyzed using RNA expression analysis and functional assays. It is shown that depsipeptide is effective at submicromolar concentrations and acts mainly by apoptosis induction, upregulation of p21 and cell cycle inhibition in G2/M. Of special note, HDAC mediated toxicity in H-RS cells does not require RelA/p65 downregulation, which was previously shown to drive the malignant phenotype of H-RS cells. In summary, depsipeptide induced protein acetylation results in transcriptional changes of a large number of pathogenetically relevant genes and increased RelA/p65 binding activity in cHL cell lines. Our preclinical data suggest that HDAC inhibition using depsipeptide might be a promising approach for the treatment of cHL patients.

Resistance to CD95-mediated apoptosis in breast cancer is not due to somatic mutation of the CD95 gene

Resistance to CD95 (Apo‐1/Fas)‐mediated apoptosis is a typical feature of breast cancer cells. Recent studies identified deleterious mutations of the CD95 gene not only in a variety of B cell lymphomas but also in a number of solid tumor entities. Therefore, we amplified and sequenced selected regions of the CD95 gene from 48 breast cancer cases and 10 cell lines but no mutation was found. In the presence of both polymorphic alleles, loss of heterozygosity was excluded in 27 informative cases. We conclude, that relevant somatic mutations of the CD95 gene occur, if at all, at a low frequency and are not the primary cause for resistance to CD95‐mediated apoptosis in breast cancer.