Expression of the c-Met oncogene by tumor cells predicts a favorable outcome in classical Hodgkin's lymphoma

Background

The c-Met signaling pathway regulates a variety of biological processes, including proliferation, survival and migration. Deregulated c-Met activation has been implicated in the pathogenesis and prognosis of many human malignancies. We studied the function and prognostic significance of c-Met and hepatocyte growth factor protein expression in patients with classical Hodgkin’s lymphoma.

Design and Methods

Expression of c-Met and its ligand, hepatocyte growth factor, were determined by immunohistochemistry. Prognostic values were defined in cohorts of German and Dutch patients with classical Hodgkin’s lymphoma. Functional studies were performed on Hodgkin’s lymphoma cell lines.

Results

Expression of c-Met was detected in the tumor cells of 52% (80/153) of the patients and expression of its ligand, hepatocyte growth factor, in 8% (10/121) of the patients. c-Met expression correlated with a 5-year freedom from tumor progression of 94%, whereas lack of expression correlated with a 5-year freedom from tumor progression of 73% (P<0.001) in the combined cohort. In multivariate analysis both c-Met (hazard ratio 5.0, 95% confidence interval 1.9–13.3, P<0.001) and stage (hazard ratio 2.8, 95% confidence interval 1.2–6.4, P=0.014) were independent predictors for freedom from tumor progression. In functional studies activation with hepatocyte growth factor did not affect cell growth, while the c-Met inhibitor SU11274 suppressed cell growth by inducing G2/M cell cycle arrest.

Conclusions

Although functional studies showed an oncogenic role of the hepatocyte growth factor/c-Met signaling pathway in cell cycle progression, expression of c-Met in tumor cells from patients with classical Hodgkin’s lymphoma strongly correlated with a favorable prognosis in two independent cohorts.     

Clonal relation in a case of CLL,ALCL, and Hodgkin composite lymphoma

Large cell lymphomas and Hodgkin disease may develop during the course of chronic lymphocytic leukemia (CLL). In some cases the transformed cells are Epstein-Barr virus (EBV)-positive and not clonally related to the CLL cells. In other cases the transformed cells have the same clonal rearrangements as the CLL cells. Here we describe a composite lymphoma in a patient with CLL that exhibits a combination of CLL/small lymphocytic lymphoma, large cell lymphoma with anaplastic morphology, and Hodgkin lymphoma (HL). Although the large cell lymphoma cells are CD45R0 and TIA-1-positive, suggesting a T- or 0-cell anaplastic large cell lymphoma (ALCL), the genetic analysis demonstrates immunoglobulin heavy chain (IgH) gene rearrangements for both alleles, carrying the same somatic mutations as observed in the CLL component. The Reed-Sternberg (R-S) cells in the Hodgkin component also strongly express TIA-1 but differ from the anaplastic large cells by the expression of CD15 and TARC and the presence of a prominent lymphocytic infiltrate. The ALCL and HL components both are EBV negative. Analysis of the IgH gene rearrangements in micromanipulated R-S cells revealed identical Ig gene rearrangements carrying the same somatic mutations as the CLL and the large cell components. The findings indicate transformation of the CLL cells into a large cell lymphoma with anaplastic morphology and a Hodgkin component.     

The significance of intracytoplasmic proteins in Reed-Sternberg cells.

Lymphoid tissue of 42 patients with Hodgkin's disease was studied with immunohistological techniques on the light microscopic and ultrastructural level. The presence of IgG in some Reed-Sternberg (R-S) cells was confirmed, and in addition serial sections and a double staining technique revealed that these cells also contained both kappa and lambda light chains. Furthermore two serum proteins, human serum albumin and alpha-1-antitrypsin, were demonstrated in the same positive R-S cells. The ultrastructural localization of the immunoglobulin and of human serum albumin was not related to any protein synthesizing organelle or to structures related to endocytosis. It is suggested that the presence of immunoglobulin in R-S cells is the result of a disturbance of the cell wall integrity with subsequent nonspecific diffusion of immunoglobulin and other serum proteins into the cell. The presence of IgG therefore can not be taken as an argument for a B-cell origin of R-S cells. Possible mechanisms for the cell wall damage are discussed.     

Molecular, cytogenetic, and immunophenotypic characterization of follicular lymphoma grade 3B; a separate entity or part of the spectrum of diffuse large B-cell lymphoma or follicular lymphoma?

We studied a histological homogeneous group of 29 cases with the diagnosis of follicular lymphoma (FL) grade 3B (FL3Bs). In a previous study, we subdivided this group in 3 subgroups based on (1) aberrations of the 3q27 region, (2) lack of 3q27 and t(14;18), and (3) the presence of a t(14;18). In this study, we further characterized the FL3B lymphomas that are currently part of the spectrum of FL in the WHO classification, taking into account other cytogenetical aberrations, immunohistochemistry for P53, bcl2, bcl6, and CD10, rearrangement of the proto-oncogene myc, and mutation of the tumor suppressor gene TP53. With respect to P53, bcl2, bcl6 expression, myc rearrangement, and TP53 mutation, FL3B represents a homogeneous group. CD10 expression and gain of chromosome 7, considered to be typical FL markers, were more common in the FL3B t(14;18)-positive subgroup. The lack of CD10 expression and gain of chromosome 7 in most cases in the other 2 subgroups suggest that those cases have a closer relation to diffuse large B-cell lymphomas.     

Development of lymphoma in Autoimmune Lymphoproliferative Syndrome (ALPS) and its relationship to Fas gene mutations

Autoimmune Lymphoproliferative Syndrome (ALPS) is generally the result of a mutation in genes associated with apoptosis, like Fas, Fas ligand, Casp 8 and Casp 10. As a result, the normal homeostasis of T- and B-lymphocytes is disturbed and a proliferation of polyclonal T lymphocytes occurs. This leads to hepatosplenomegaly and lymphadenopathy and in most patients also to autoimmune phenomena like anemia and thrombocytopenia. The proliferating T cells are TCRalphabeta and/or TCRgammadelta positive but lack both CD4 and CD8. Hence they are termed double negative (DN) T cells. In addition, there is an increase of CD5 positive B cells. Individuals with germline mutations in the Fas gene have a high risk to develop non Hodgkin lymphomas (x 14) as well as Hodgkin lymphomas (x 51), in particular NLP Hodgkin lymphoma. Somatic mutations of Fas are frequently acquired during the normal germinal center reaction. Non Hodgkin lymphomas carry somatic mutations of the Fas gene in 11% and of the Casp 10 gene in 14.5% of the patients. In Hodgkin lymphomas, Fas mutations can be demonstrated in Reed-Sternberg cells in 10-20% of the patients. These data implicate a role for Fas-mediated apoptosis in preventing lymphomas. Inherited defects in receptor-mediated lymphocyte apoptosis represent a risk factor for lymphomas and somatic mutations of these genes may also play a role in the development and/or progression of lymphomas.     

Diagnostic application of a monoclonal antibody against small cell lung cancer

A monoclonal antibody (MOC-1) directed against an antigen present in small cell lung cancer (SCLC) was used for diagnostic purposes. After screening of biopsy specimens of lung tumors, MOC-1 was found to react with SCLC (n = 10) and adenocarcinoma of the lung (4 of 9 cases). Except for a few cells in a poorly differentiated tumor, the reaction with squamous cell cancer was negative (n = 6). Staining with MOC-1 by an immunoperoxidase technique on imprints of biopsy specimens procured by rigid bronchoscopy was found to be a reliable and rapid method for diagnosing SCLC (16 of 17 positive). All cytologically proven bone marrow and pleural metastases of SCLC were found by staining on a cytospin preparation with MOC-1. Moreover, in three cytologically negative cases, MOC-1-positive cells were detected.     

FAS gene mutation in a case of autoimmune lymphoproliferative syndrome type IA with accumulation of gammadelta+ T cells

A 6-month-old girl presented to the hospital with cervical lymphadenopathy and hepatosplenomegaly. She was known to have an enlarged spleen, anemia, and thrombocytopenia since the age of 1 month. A lymph node biopsy showed a diffuse proliferation of blasts with few remnants of follicles. The blasts were CD3+CD57+CD4-CD8-, consistent with the usual autoimmune lymphoproliferative syndrome phenotype. However, these double negative T cells stained positive for gammadelta T-cell receptors, whereas double negative T cells in patients with autoimmune lymphoproliferative syndrome usually bear alphabeta T-cell receptor. Mutation analysis of the FAS gene revealed a mutation in the death domain of the FAS gene, which is a frequent finding in patients with autoimmune lymphoproliferative syndrome. Based on these results, the diagnosis of autoimmune lymphoproliferative syndrome was established. RT-PCR analysis of the affected lymph node tissue revealed a strong upregulation of interleukin 10 and a moderate upregulation of interferon-gamma expression compared with normal tissue. Our findings indicate that autoimmune lymphoproliferative syndrome can result in a prominent proliferation of gammadelta+ double negative T cells. It is important to distinguish this benign polyclonal proliferation from neoplastic gammadelta+ T-cell proliferations, such as hepatosplenic gammadelta T-cell lymphomas. Factors contributing to the accumulation of these gammadelta+ double negative T cells may be an unidentified infection in combination with the young age of onset in this patient.     

The human leukocyte antigen class I region is associated with EBV-positive Hodgkin's lymphoma: HLA-A and HLA complex group 9 are putative candidate genes.

Various studies have indicated that the human leukocyte antigen (HLA) region is associated with Hodgkin's lymphoma. We recently showed a specific association of the HLA class I region with EBV-positive Hodgkin's lymphoma cases. One haplotype of two consecutive microsatellite markers (D6S265 and D6S510) was overrepresented in the patient group, whereas another haplotype was underrepresented. Here, we did fine mapping of this region of approximately 400 kb as a next step to find the causative single-nucleotide polymorphism(s) (SNP). To select candidate SNPs for screening the total study population, several known SNPs were determined by sequencing two individuals homozygous for either of the above-mentioned associated haplotypes. Seven SNPs displayed different alleles in these two individuals and were therefore analyzed in the total study population, including 238 Hodgkin's lymphoma patients and 365 family-based controls. All seven SNPs showed significant association with the EBV-positive patient group. Two of these SNPs were analyzed in a Scottish Hodgkin's lymphoma population and revealed significant associations as well. The associated SNPs are located nearby two putative candidate genes: HLA-A and HLA complex group 9. HLA-A represents the most interesting target because of its consistent expression in EBV-positive Hodgkin's lymphoma cases and its ability to present EBV-derived peptides to cytotoxic T cells.     

The finest branches of the biliary tree might induce biliary vascularization necessary for biliary regeneration

BACKGROUND/AIMS: The finer branches of the biliary tree play an important role in biliary regeneration. They are consistently escorted by microvessels. Defects in the vascularization of these structures could impair bile duct regeneration. Therefore, we investigated the pattern of the escorting microvessels during the development of bile duct loss in the human liver, using chronic rejection as a model. METHODS: The number of interlobular bile ducts, bile ductules and extraportal biliary cells with and without escorting microvessels and the expression of VEGF-A were studied in follow-up biopsies of 12 patients with chronic rejection and 16 control patients with acute rejection without progression to chronic rejection. RESULTS: The controls showed a proliferation of bile ductules at 1-week and 1-month. Proliferation of bile ductules without microvessels preceded proliferation of bile ductules with microvessels. Proliferation of the microvascular compartment followed biliary proliferation. This sequence of events was not observed in the chronic rejection group, in which all biliary structures decreased in time. VEGF-A expression was increased at 1-week and 1-month in both groups. CONCLUSIONS: An immediate proliferative response of the finer branches of the biliary tree followed by proliferation of the microvascular compartment after biliary injury seems to be a prerequisite for bile duct regeneration.