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Purpose: We studied work-related issues in long-term survivors of Hodgkin lymphoma [HLSs] who had undergone treatment according to contemporary stage risk-adapted approaches. At survey, work changes and problems since diagnosis, comparisons of HLSs with low/moderate versus high work ability, associations between work issues, and late adverse effects [LAEs] were examined. Methods: This cross-sectional questionnaire-based study included HLSs treated from 1997 to 2006 and alive at the end of 2016. They completed a mailed questionnaire including work and health-related issues. Results: Among 518 invited HLSs, 297 (58%) completed the work-related issues, and 48% of them were females. Mean age at survey was 45.9 years, and mean time was 16.7 years since diagnosis. At follow-up, 71% of the HLSs held paid work and 19% were on disability pension. Only 3% of HLSs did not hold paid work at any time after diagnosis. In total, 43% HLSs had low/moderate and 57% high work ability at follow-up. Low/moderate work ability was significantly associated with older age, female sex, more LAEs, disability pension, lower household income, distressed personality, obesity, fatigue, and mental disorders. More LAEs were significantly associated with more work problems. Conclusions: Many HLSs manage to stay in the work force. Several health problems and LAEs amenable for interventions are significantly associated with low/moderate work ability and emphasize the importance of focus on these issues in long-term follow-up. Implications for Cancer Survivors: HLSs in paid work at diagnosis can be optimistic as to their future participation in work life. Screening and treatment for health problems such as LAEs may improve work ability. [ABSTRACT FROM AUTHOR]

Chronic fatigue (CF), substantial fatigue for ≥ six months, can manifest as a late effect (LE) after cancer treatment, and may affect several aspects of life. In a Norwegian cohort of Hodgkin's lymphoma survivors (HLS), more than a decade after contemporary risk-adapted treatment regimens with limited use of radiotherapy (RT), we assessed: (1) Prevalence of, (2) factors associated with (3) and implications of CF on socioeconomic status (SES) and work ability (WA). HLS treated between 1997–2006, aged 8–49 years at diagnosis, were invited to participate in a population-based cross-sectional study on late effects in 2018–2019. In a mailed questionnaire, HLS responded to a fatigue questionnaire (FQ), work ability score (WAS) and short-form health survey (SF-36). Disease- and treatment data were extracted from hospital records. Factors associated with CF were identified by uni- and multivariate analysis. To study the implications of CF on SES and WA, a multinomial regression analysis was performed. Invitations were extended to 518 HLS and 298 (58%) responded to FQ, of whom 42% had CF with mean (standard deviation [SD]) physical- and mental fatigue scores of 10.2 (4.3) and 5.5 (2.1) respectively. Median age at survey was 45 years, 47% were females. In multivariate analysis female sex (p = 0.03), lower education (p = 0.03), body mass index ≥30 kg/m2 (p = 0.04), and an increasing number of comorbidities (p = 0.01) were associated with CF. No association with disease stage, chemotherapy or RT was found. CF was associated with poorer WAS scores at survey (p < 0.001), unemployment (p = 0.03), and receiving disability pension (p = 0.003). After risk-adapted treatment, CF is still a frequent LE among long-term HLS, without apparent association with disease or treatment-related parameters. CF is associated with reduced WA and SES. As no apparent risk reduction is seen with contemporary treatment, further studies should emphasize etiological factors of CF and treatment to alleviate this common LE. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate the diagnostic performance of FDG PET/MR compared to PET/CT in a patient cohort including Hodgkins lymphoma, diffuse large B-cell lymphoma, and high-grade B-cell lymphoma at baseline and response assessment. Sixty-one patients were examined with FDG PET/CT directly followed by PET/MR. Images were read by two pairs of nuclear medicine physicians and radiologists. Concordance for lymphoma involvement between PET/MR and the reference standard PET/CT was assessed at baseline and response assessment. Correlation of prognostic biomarkers Deauville score, criteria of response, SUVmax, SUVpeak, and MTV was performed between PET/MR and PET/CT. Baseline FDG PET/MR showed a sensitivity of 92.5% and a specificity 97.9% compared to the reference standard PET/CT (κ 0.91) for nodal sites. For extranodal sites, a sensitivity of 80.4% and a specificity of 99.5% were found (κ 0.84). Concordance in Ann Arbor was found in 57 of 61 patients (κ 0.92). Discrepancies were due to misclassification of region and not lesion detection. In response assessment, a sensitivity of 100% and a specificity 99.9% for all sites combined were found (κ 0.92). There was a perfect agreement on Deauville scores 4 and 5 and criteria of response between the two modalities. Intraclass correlation coefficient (ICC) for SUVmax, SUVpeak, and MTV values showed excellent reliability (ICC > 0.9). FDG PET/MR is a reliable alternative to PET/CT in this patient population, both in terms of lesion detection at baseline staging and response assessment, and for quantitative prognostic imaging biomarkers. [ABSTRACT FROM AUTHOR]

Presently, bed-side or at home quantification of neutrophils in blood (b-neutrophils) is not practical, because cytometric methods are too expensive and technically demanding. We have explored whether calprotectin concentration in whole blood (b-calprotectin) might be a valid measure of b-neutrophils because this principle might be used in a simple and robust immunoassay device. We obtained heparin blood samples from 77 patients with possible neutropenia, most of them cancer patients treated with cytostatic drugs, and compared b-calprotectin with their b-neutrophils in a simultaneously taken EDTA-blood sample. The Spearman rank correlation coefficient between b-calprotectin and b-neutrophils was 0.986 (p <.0001). In a regression model of b-neutrophils as a function of age, gender, type of hematology instrument, total leukocyte count minus neutrophils, b-calprotectin, and plasma calprotectin (p-calprotectin), only b-calprotectin was a statistically significant predictor. B-neutrophils below 1 × 109/L was unlikely if b-calprotectin was above 50 mg/L. In conclusion, b-calprotectin, without adjusting for p-calprotectin, correlates closely with b-neutrophils and could be used to detect b-neutrophils below 1 × 109/L. [ABSTRACT FROM AUTHOR]

Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting side effect of Hodgkin's lymphoma (HL) treatment. We aimed to describe the prevalence of CIPN associated symptoms in long-term HL survivors compared to controls, and determine associated factors, including impact on health-related quality of life (HRQoL). A questionnaire, including EORTC QLQ-CIPN-20 for CIPN related symptoms and SF-36 for HRQoL, was completed by 303 HL survivors at a median of 16 years after diagnosis. CIPN results were compared to a normative population (n = 606). CIPN associated factors were identified by linear regression analysis. Total CIPN score and subscores were significantly higher in HL survivors compared to controls. In multivariate analysis of HL survivors, a number of comorbidities (p < 0.001) and female gender (p = 0.05) were significantly associated with more CIPN. No association with disease or treatment factors was found. In a multivariate analysis including survivors and controls, the number of comorbidities (p < 0.001) and caseness (p < 0.001) were significantly associated with more CIPN. In HL survivors higher CIPN score was associated with reduced HRQoL (p < 0.001). HL survivors more than a decade after treatment report higher neuropathy-related symptom burden than controls, with a negative impact on HRQoL. Symptoms may be related to factors other than neurotoxic chemotherapy. [ABSTRACT FROM AUTHOR]

Background: This study describes post-treatment work patterns in lymphoma survivors treated with high-dose chemotherapy with autologous stem-cell transplantation (HDT-ASCT). It aims to identify determinants for labour force participation and exclusion after HDT-ASCT.Methods: All survivors treated with HDT-ASCT for lymphoma in Norway between 1995 and 2008, aged ≥18 years at HDT-ASCT and alive at survey in 2012-2013 were eligible. We divide survivors by current employment status (full-time, part-time and unemployed). Main outcomes are current employment status, work hours and work ability. Withdrawals are patients employed when diagnosed but not before HDT-ASCT.Results: Of the 274 who completed the survey, 82% (N = 225) were included in the final analyses. Mean age at survey was 52 years, 39% were female, 85% were employed when diagnosed, 77% before HDT-ASCT and 69% at survey. Employment before HDT-ASCT corresponds with a higher probability of employment at survey for a given symptom burden. In the most extensive statistical model, it increases with 37.3 percentage points. Work hours amongst withdrawals plummet after HDT-ASCT while work ability shows a rebound effect. The potential economic gain from their re-enter into the work force equals 70% of the average annual wage in Norway in 2012.Conclusions: For a given symptom burden, staying employed throughout diagnosis and treatment is associated with a higher probability of future employment. These results favour policies for labour force inclusion past diagnosis and treatment increasing cancer survivors' probability of future employment. However, we need more research on withdrawal mechanisms, and on policy measures that promote inclusion. [ABSTRACT FROM AUTHOR]

The article describes the experience with Brentuximab vedotin (BV) antibody-drug conjugate in r/r cHL in Norway for patients treated with the approved indications from 2011 to 2016. Highlights include consolidation of responses to BV achieved through radiotherapy in isolated patients, approval of the study by the South East Regional Committee for Medical and Health Research Ethics, and comparison of patients treated with BV and a population-based historical cohort.

Purpose: Lymphoma survivors after high dose therapy with autologous stem cell therapy (HD-ASCT) are at high risk for late adverse effects (AEs). Information patients receive and collect throughout their cancer trajectory about diagnosis, treatment schedule and risks of AEs may influence attitudes and health-related behavior in the years after treatment. The purpose of this study was to explore level of knowledge in lymphoma survivors after HD-ASCT at a median of 12 years after primary diagnosis. Material and methods: From a national study on the effects of HD-ASCT for lymphomas, 269 survivors met for an outpatient examination, including a structured interview addressing knowledge about diagnosis and treatment. Survivors were also asked whether they knew and/or had experienced certain common late AEs. Numbers of recognized and experienced late AEs were presented as sum scores. Factors associated with the level of knowledge of late AEs were analyzed by linear regression analysis. Results: Eighty-one percent of the survivors knew their diagnosis, 99% knew the components of HD-ASCT and 97% correctly recalled having had radiotherapy. Ninety percent reported awareness of late AEs, but the level of knowledge and personal experience with specified AEs varied. Thirty-five percent of survivors stated to have received follow-up for late AEs. In multivariable analysis younger age at diagnosis, having received mediastinal radiotherapy, higher mental health related quality of life, a higher number of self-experienced late AEs and having received follow-up care for late AEs were significantly associated with a higher level of knowledge of AEs. Conclusion: The majority of lymphoma survivors treated with HD-ASCT correctly recalled diagnosis and treatment, while knowledge of late AEs varied. Our findings point to information deficits in survivors at older age and with lower mental health related quality of life. They indicate benefit of follow-up to enhance education on late AEs in lymphoma survivors. [ABSTRACT FROM AUTHOR]

Introduction: High-dose therapy with autologous stem cell transplantation (HD-ASCT) is associated with an increased risk of late effects. Our aim was to assess lifestyle behavior and factors associated with unhealthy lifestyle among HD-ASCT-treated lymphoma survivors (HD-ASCT-LS). Materials and methods: We conducted a national cross-sectional study of HD-ASCT-LS treated during 1987–2008. Among 399 eligible participants, 312 (78%) completed patient-reported outcome measures (PROMs) on lifestyle behavior (physical activity, overweight, smoking and alcohol consumption), chronic fatigue (CF) and somatic and mental illness. We assessed lifestyle according to WHO recommendations. Multivariable logistic regression models were used to study associations between variables. A comparison to the general population was performed. Results: Mean age at survey was 54.6 years, 60% were men, 55% sedentary, 55% overweight, 18% smokers and 5% had unhealthy alcohol consumption. Being sedentary was positively associated with older age, low household income, CF and higher somatic burden (≥4 self-reported somatic conditions). Overweight was positively associated with male gender and negatively associated with increased number of chemotherapy regimens prior to HD-ASCT. Current smoking was positively associated with living alone and CF, and negatively associated with older age. Male gender, CF and higher somatic burden increased the risk of an unhealthier lifestyle whereas the increased number of chemotherapy regimens prior to HD-ASCT decreased the risk. HD-ASCT-LS were significantly less sedentary, less overweight, and had a lower likelihood of smoking than the controls. Discussion: Assessed by PROMs, unhealthy habits were frequent among HD-ASCT-LS and associated with comorbidity. Nevertheless, compared with controls significantly more HD-ASCT-LS met lifestyle recommendations. These results indicate that the HD-ASCT-LS may consist of two groups, the adhering group with less comorbidity and the non-adhering group with more comorbidity. Our findings illustrate the necessity of recommendations and support for improving health-related behavior in cancer survivorship plans in order to empower survivors in their life beyond cancer. [ABSTRACT FROM AUTHOR]

The nuclease Artemis is essential for the development of T-cell and B-cell receptors and repair of DNA double-strand breaks, and a loss of expression or function will lead to a radiosensitive severe combined immunodeficiency with no functional T-cells or B-cells (T-B-SCID). Hypomorphic mutations in the Artemis gene can lead to a functional, but reduced, T-cell and B-cell repertoire with a more indolent clinical course called “leaky” SCID. Here, we present the case of a young man who had increasingly aggressive lymphoproliferative skin lesions from 2 years of age which developed into multiple EBV+ B-cell lymphomas, where a hypomorphic mutation in the Artemis gene was found in a diagnostic race against time using whole exome sequencing. The patient was given a haploidentical stem cell transplant while in remission for his lymphomas and although the initial course was successful, he succumbed to a serious Pneumocystis jirovecii pneumonia 5 months after the transplant. The case underscores the importance of next-generation sequencing in the diagnosis of patients with suspected severe immunodeficiency. [ABSTRACT FROM AUTHOR]

This national population-based study aimed to investigate conditional survival and standardized mortality ratios ( SMR) after high-dose therapy with autologous stem-cell transplantation ( HDT- ASCT) for non-Hodgkin lymphoma ( NHL), and to analyse cause of death, relapses and second malignancies. All patients ≥18 years treated with HDT- ASCT for NHL in Norway between 1987 and 2008 were included ( n = 578). Information from the Cause of Death Registry and Cancer Registry of Norway were linked with clinical data. The 5-, 10- and 20-year overall survival was 61% (95% confidence interval [ CI] 56-64%), 52% (95% CI 48-56%) and 45% (95% CI 40-50%), respectively. The 5-year survival conditional on having survived 2, 5 and 10 years after HDT- ASCT was 81%, 86% and 93%. SMRs were 12·3 (95% CI 11·0-13·9), 4·9 (95% CI 4·1-5·9), 2·4 (95% CI 1·8-3·2) and 1·0 (95% CI 0·6-1·8) for the entire cohort and for patients having survived 2, 5 and 10 years after HDT- ASCT respectively. Of the 281 deaths observed, 77% were relapse-related. Treatment-related mortality was 3·6%. The 10-year cumulative incidence of second malignancies was 7·9% and standardized incidence ratio was 2·0 (95% CI 1·5-2·6). NHL patients treated with HDT- ASCT were at increased risk of second cancer and premature death. The mortality was still elevated at 5 years, but after 10 years mortality equalled that of the general population. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this prospective study was to investigate the prognostic value of metabolic tumor volume (MTV) and apparent diffusion coefficient (ADC) from baseline FDG PET/MRI compared to established clinical risk factors in terms of progression free survival (PFS) at 2 years in a cohort of diffuse large B-cell Lymphoma (DLBCL) and high-grade-B-cell lymphoma (HGBCL).Methods: Thirty-three patients and their baseline PET/MRI examinations were included. Images were read by two pairs of nuclear medicine physicians and radiologists for defining lymphoma lesions. MTV was computed on PET, and up to six lymphoma target lesions with restricted diffusion was defined for each PET/MRI examination. Minimum ADC (ADCmin) and the corresponding mean ADC (ADCmean) from the target lesion with the lowest ADCmin were included in the analyses. For the combined PET/MRI parameters, the ratio between MTV and the target lesion with the lowest ADCmin (MTV/ADCmin) and the corresponding ADCmean (MTV/ADCmean) was calculated for each patient. Clinical, histological, and PET/MRI parameters were compared between the treatment failure and treatment response group, while survival analyses for each variable was performed by using univariate Cox regression. In case of significant variables in the Cox regression analyses, Kaplan-Meier survival analyses with log-rank test was used to study the effect of the variables on PFS.Results: ECOC PS scale ≥2 (p = 0.05) and ADCmean (p = 0.05) were significantly different between the treatment failure group (n = 6) and those with treatment response (n = 27). Survival analyses showed that ADCmean was associated with PFS (p = 0.02, [HR 2.3 for 1 SD increase]), while combining MTV and ADC did not predict outcome. In addition, ECOG PS ≥2 (p = 0.01, [HR 13.3]) and histology of HGBCL (p = 0.02 [HR 7.6]) was significantly associated with PFS.Conclusions: ADCmean derived from baseline MRI could be a prognostic imaging biomarker for DLBCL and HGBCL. Baseline staging with PET/MRI could therefore give supplementary prognostic information compared to today's standard PET/CT. [ABSTRACT FROM AUTHOR]

One of the greatest challenges in PET/MR imaging is that of accurate MR-based attenuation correction (AC) of the acquired PET data, which must be solved if the PET/MR modality is to reach its full potential. The aim of this study was to investigate the performance of Siemens' most recent version (VB20P) of MR-based AC of head PET data, by comparing it to CT-based AC. Methods:F-FDG PET data from seven lymphoma and twelve lung cancer patients examined with a Biograph mMR PET/MR system were reconstructed with both CT-based and MR-based AC, avoiding sources of error arising when comparing PET data from different systems. The resulting images were compared quantitatively by measuring changes in mean SUV in ten different brain regions in both hemispheres, as well as the brainstem. In addition, the attenuation maps (μ maps) were compared regarding volume and localization of cranial bone. Results: The UTE μ maps clearly overestimate the amount of bone in the neck, while slightly underestimating the amount of bone in the cranium, and the localization of bone in the cranial region also differ from the CT μ maps. In air/tissue interfaces in the sinuses and ears, the MRAC method struggles to correctly classify the different tissues. The misclassification of tissue is most likely caused by a combination of artefacts and the insufficiency of the UTE method to accurately separate bone. Quantitatively, this results in a combination of overestimation (0.5-3.6 %) and underestimation (2.7-5.2 %) of PET activity throughout the brain, depending on the proximity to the inaccurate regions. Conclusions: Our results indicate that the performance of the UTE method as implemented in VB20P is close to the theoretical maximum of such an MRAC method in the brain, while it does not perform satisfactorily in the neck or face/nasal area. Further improvement of the UTE MRAC or other available methods for more accurate segmentation of bone should be incorporated. [ABSTRACT FROM AUTHOR]

Objectives: The receptor tyrosine kinase c-Met and its ligand, hepatocyte growth factor (HGF), play key roles in tumour genesis and metastasis and contribute in multiple myeloma pathogenesis. Substantial data support that a soluble extracellular fragment of c-Met may function as a decoy receptor that downregulates the biological effects of HGF and c-Met. We examined serum levels of soluble c-Met in patients with myeloma and healthy individuals and investigated a possible relationship with clinical disease parameters and survival. Methods: The concentration of c-Met and HGF was measured by enzyme-linked immunosorbent assay in serum ( n = 49) and bone marrow plasma ( n = 16) from patients with multiple myeloma and in serum from healthy controls ( n = 26). Results: The median serum concentration of soluble c-Met was 186 ng/mL (range 22-562) in patients with multiple myeloma and 189 ng/mL (range 124-397) in healthy individuals. There was a significant negative correlation between serum c-Met levels and disease stage, bone marrow plasma cell percentage and serum concentration of M-protein. Conclusion: We have for the first time examined the concentration of soluble c-Met in serum from patients with myeloma and found equal median levels in patients with myeloma as a group and healthy individuals. Still, serum levels of soluble c-Met correlated negatively with parameters of disease burden in patients with myeloma. We suggest that a possible role for the c-Met ectodomain as a negative regulator of HGF/c-Met activity should be examined in multiple myeloma. [ABSTRACT FROM AUTHOR]

Background: BCL3 is a putative oncogene encoding for a protein belonging to the inhibitory κB-family. We experienced that this putative oncogene was a common target gene for growth-promoting cytokines in myeloma cell lines. Methods: Gene expression of BCL3 was studied in 351 newly diagnosed myeloma patients, 12 patients with smouldering myeloma, 44 patients with monoclonal gammopathy of undetermined significance and 22 healthy individuals. Smaller material of samples was included for mRNA detection by RT-PCR, protein detection by Western blot and immunohistochemistry, and for cytogenetic studies. A total of eight different myeloma cell lines were studied. Results: Bcl-3 was induced in myeloma cell lines by interleukin (IL)-6, IL-21, IL-15, tumor necrosis factor-α and IGF-1, and its upregulation was associated with increased proliferation of the cells. In a population of 351 patients, expression levels of BCL3 above 75th percentile were associated with shorter 5-yr survival. When this patient population was divided into subgroups based on molecular classification, BCL3 was significantly increased in a poor risk subgroup characterized by overexpression of cell cycle and proliferation related genes. Intracellular localization of Bcl-3 was dependent on type of stimulus given to the cell. Conclusion: BCL3 is a common target gene for several growth-promoting cytokines in myeloma cells and high expression of BCL3 at the time of diagnosis is associated with poor prognosis of patients with multiple myeloma (MM). These data may indicate a potential oncogenic role for Bcl-3 in MM. [ABSTRACT FROM AUTHOR]

Objectives: Hepatocyte growth factor (HGF) is a constituent of the myeloma microenvironment and is elevated in sera from myeloma patients compared to healthy individuals. Increased levels of serum HGF predict a poor prognosis. It has previously been shown by us and others HGF can act as a growth factor to myeloma cells in vitro although these effects have been moderate. We therefore wanted to investigate if HGF could influence the effects of interleukin (IL)-6. Methods: Myeloma cell lines and primary samples were tested for the combined effects of IL-6 and HGF in inducing DNA synthesis and migration. Expression levels of c-Met protein were analysed by Western blotting and flow cytometry. Signaling pathways were examined by Western blotting using phosphospecific antibodies and a Ras-GTP pull down assay. Results: HGF potentiated IL-6-induced growth in human myeloma cell lines and in purified primary myeloma cells. There was also cooperation between HGF and IL-6 in induction of migration. There seemed to be two explanations for this synergy. IL-6-treatment increased the expression of c-Met making cells HGF responsive, and IL-6 was dependent on c-Met signaling in activating both Ras and p44/42 MAPK by a mechanism involving the tyrosine phosphatase Shp2. Conclusions: The results indicate that besides from being a myeloma growth factor alone, HGF can also potentiate the effects of IL-6 in myeloma proliferation and migration. Thus, c-Met signaling could be a target for therapy of multiple myeloma. [ABSTRACT FROM AUTHOR]

Background: Phosphatase of regenerating liver-3 (PRL-3) is implicated in oncogenesis of hematological and solid cancers. PRL-3 expression increases metastatic potential, invasiveness and is associated with poor prognosis. With this study, we aimed to show a possible oncogenic role of PRL-3 in classical Hodgkin lymphoma (cHL). Methods: PRL-3 expression was measured in 25 cHL patients by immunohistochemistry and gene expression was analyzed from microdissected malignant cells. We knocked down PRL-3 in the cHL cell lines L1236 and HDLM2 and used small molecular inhibitors against PRL-3 to investigate proliferation, migration and cytokine production. Results: PRL-3 protein was expressed in 16% of patient samples. In three different gene expression datasets, PRL-3 was significantly overexpressed compared to normal controls. PRL-3 knockdown reduced proliferation, viability and Mcl-1 expression in L1236, but not in HDLM2 cells. Thienopyridone, a small molecule inhibitor of PRL-3, reduced proliferation of both L1236 and HDLM2. PRL-3 affected IL-13 secretion and enhanced STAT6 signaling. IL-13 stimulation partially rescued proliferation in L1236 cells after knockdown of PRL-3. PRL-3 knockdown reduced migration in both L1236 and HDLM2 cells. Conclusion: PRL-3 was overexpressed in a subset of cHL patients. Inhibition of PRL-3 increased IL-13 cytokine production and reduced migration, proliferation and viability. The effects could be mediated through regulation of the anti-apoptotic molecule Mcl-1 and a feedback loop of IL-13 mediated activation of STAT6. This point to a role for PRL-3 in the pathogenesis of Hodgkin lymphoma, and PRL-3 could be a possible new drug target. [ABSTRACT FROM AUTHOR]

Wader K F, Fagerli U-M, Børset M, Lydersen S, Hov H, Sundan A, Bofin A & Waage A (2012) Histopathology 60,443-451 Immunohistochemical analysis of hepatocyte growth factor and c-Met in plasma cell disease Aims: Interaction with the bone marrow microenvironment is important for homing and survival of myeloma cells. One cytokine involved in this process is hepatocyte growth factor (HGF). HGF, by binding to the receptor tyrosine kinase c-Met, mediates a broad range of tumour progression activities. Our aims were to investigate whether HGF and c-Met are present in bone marrow and extramedullary tumours from patients with monoclonal plasma cell disease, and whether c-Met is activated. Methods and results: Expression of HGF, c-Met and phospho-c-Met was studied by immunohistochemistry in biopsies from 80 patients with monoclonal plasma cell disease. Cytoplasmic staining for HGF in plasma cells was demonstrated in 58 of 68 biopsies from multiple myeloma patients (85%), but also in biopsies from nine of 10 healthy individuals. Membranous staining for c-Met was found in 25 of 63 multiple myeloma patients (40%) and in none of 10 healthy individuals. Membranous staining for phospho-c-Met was found in biopsies from 15 of 21 c-Met-positive myeloma patients (71%). Conclusions: Our data point to c-Met expression as one of the factors that distinguishes normal from malignant plasma cells, and indicate that the HGF/c-Met system is activated in multiple myeloma patients. [ABSTRACT FROM AUTHOR]