Cytogenetic investigations in Hodgkin's disease: I. Involvement of specific chromosomes in marker formation

Melittin Increases Cisplatin Sensitivity and Kills KM-H2 and L-428 Hodgkin Lymphoma Cells

Hodgkin lymphoma (HL) is neoplasia with high cure rates. However, not all patients can be cured with the current treatment. Chemo-resistance of tumor cells is one factor involved in treatment failure. In addition to its pore-forming activity on lipid bilayer membranes, the toxin melittin from bee venom is an inhibitor of several cancer-related signaling pathways. Moreover, melittin analogs have been shown to inhibit the activity of ATP binding cassette (ABC) transporters which are known to play important roles in the chemo-resistance of tumor cells. Therefore, we tested the toxicity of melittin for HL cell lines KM-H2 and L-428 and whether melittin can increase the chemo-sensitivity of cisplatin-resistant HL cells. We found high toxicity of melittin for KM-H2 and L-428 cells. In co-cultures with normal blood cells, melittin preferentially killed KM-H2 and L-428 cells. In addition, we observed increased cisplatin sensitivity of chemo-resistant L-428 cells after treatment with melittin. ABC transporter activity was not reduced after treatment with melittin. Our data suggest that melittin or melittin analogs might be promising agents for the future development of treatment strategies for HL patients with resistant disease.

Tumorigenic potential of mononucleated small cells of Hodgkin lymphoma cell lines

Tumor cells with tumorigenic potential are limited to a small cell population known as cancer stem cells (CSCs). CSCs yield both CSCs and non-CSCs, whereas non-CSCs do not yield CSCs. CSCs have not been identified in any malignant lymphomas. Hodgkin lymphoma (HL) is a mostly B-cell neoplasm that can be diagnosed by the presence of multinucleated (Reed-Sternberg; RS) cells admixed with Hodgkin cells with distinct nucleoli and various inflammatory cells. Here, the tumorigenic potential of cells with a single nucleus (S) and cells with multiple nuclei (M), which may be equivalent to Hodgkin and RS cells, respectively, was examined in HL cell lines L1236 and L428. Cultures of single S cells yielded both S and M cells, whereas M cell cultures yielded only M cells. When either cultured in methylcellulose or inoculated into NOD/SCID mice, the colony number and tumor size were both larger in S than in M cells. Concentrations of intracellular reactive oxygen species (ROS) were at low levels in a portion of S cells that abundantly expressed FoxO3a, a transcription factor that regulates ROS-degrading enzymes. In clinical samples of HL, FoxO3a was expressed in mononuclear Hodgkin cells but not in multinucleated RS cells. These findings suggest that smaller cells or Hodgkin cells that show low-ROS concentrations and high FoxO3a expression levels might be candidates for HL CSCs.

Oncolytic rat parvovirus H-1PV, a candidate for the treatment of human lymphoma: In vitro and in vivo studies

The incidence of lymphomas developing in both immunocompetent and immunosuppressed patients continues to steadily increase worldwide. Current chemotherapy and immunotherapy approaches have several limitations, such as severe side toxicity and selection of resistant cell variants. Autonomous parvoviruses (PVs), in particular the rat parvovirus H-1PV, have emerged as promising anticancer agents. Although it is apathogenic in humans, H-1PV has been shown to infect and suppress various rat and human tumors in animal models. In this study, we demonstrate the capacity of H-1PV for efficiently killing, through necrosis, cell cultures originating from Burkitt's lymphoma (BL), while sparing normal B lymphocytes. The cytotoxic effect was generally accompanied by a productive H-1PV infection. Remarkably, parvovirus-based monotherapy efficiently suppressed established BL at an advanced stage in a severe combined immunodeficient (SCID) mouse model of the disease. The data show for the first time that an oncolytic parvovirus deserves further consideration as a potential tool for the treatment of some non-Hodgkin B-cell lymphomas, including those resistant to apoptosis induction by rituximab.

An unbalanced translocation involving chromosome 14 is the probable cause for loss of potentially functional rearranged immunoglobulin heavy chain genes in the Epstein-Barr virus-positive Hodgkin's lymphoma-derived cell line L591

In the vast majority of cases, Hodgkin-Reed Sternberg (H-RS) cells, the malignant cells in Hodgkin's lymphoma (HL), are derived from germinal centre B cells. In some cases, somatic mutations within the rearranged immunoglobulin heavy (IgH) chain genes were detected, rendering potentially functional gene rearrangements non-functional. In these H-RS cells the expression of high-affinity B-cell receptors (BCR) was prevented. As in other cases only one non-productive IgH chain gene rearrangement was amplified from H-RS cells, it was speculated whether, in these cases, the functionally rearranged IgH chain genes were lost. An alternative explanation might be that the rearranged genes could not be amplified owing to a high load of somatic mutations within the primer binding sites. Here, we showed that, in the HL-derived Epstein-Barr virus (EBV)-positive cell line L591, only one non-functional somatically mutated IgH gene rearrangement could be detected. The other potentially functional IgH gene rearrangement was lost as a result of an unbalanced translocation affecting the long arm of chromosome 14. Moreover, L591 cells express the EBV latent membrane proteins LMP1 and LMP2A, which might have contributed to the 'escape' of these cells from apoptosis within the germinal centre. We conclude that, apart from the introduction of 'crippling mutations' into the rearranged VDJ genes rearrangement, deletions of the IGH locus may be regarded as another mechanism to prevent the expression of a BCR in H-RS cells.

Expression of CD44 and CD44v6 in primary cutaneous CD30 positive T-cell lymphoproliferative disorders

BACKGROUND

Expression of the lymphocyte homing receptor CD44 and its variant form, CD44v6, have been linked to unfavorable prognosis and tumor dissemination in non-Hodgkin's lymphoma. The role of CD44 and CD44v6 in primary cutaneous lymphomas may not necessarily correlate with that observed in nodal lymphomas. Our study attempts to evaluate the expression pattern of CD44 and CD44v6 in primary cutaneous CD30 positive T-cell lymphoproliferative disorders including primary cutaneous anaplastic large cell lymphoma (cALCL) and lymphomatoid papulosis (LyP) and compared the expression between these two subgroups.

METHODS

Immunohistochemical staining of CD44 and CD44v6 was performed on 10 cALCL and 18 LyP cases.

RESULTS

CD44 consistently expressed in all cases of primary cutaneous CD30 positive T-cell lymphoproliferative disorders. In contrast with previous studies, our results showed that CD44v6 expressed in 46% of all cases, including 50% cALCL and 44% LyP. There was no statistic difference in expression of CD44 or CD44v6 between cALCL and LyP subgroups.

CONCLUSIONS

These results provide a new evidence that CD44v6 is expressed in a subset cases of primary cutaneous CD30 positive T-cell lymphoproliferative disorders and suggest that other factors or molecules rather than CD44 or CD44v6 are responsible for the difference between cALCL and LyP.

Cytogenetics of Hodgkin's disease

Cytogenetic studies over the past 35 years have made a major contribution towards the understanding of the nature of Hodgkin's disease by demonstrating unequivocally the consistent presence of a clonal population of cells that have the cardinal features of malignancy e.g. more or less gross aneuploidy, frequently with complex chromosomal changes and showing considerable variation from case to case, thus comparable to the findings in carcinomas and other solid cancers. The mode is frequently in the triploid-tetraploid region, as we found in 17 of 27 cases studied in this laboratory by Feulgen microspectrophotometry, compared to only 10 cases with neardiploid modes. It is disappointing that no specific change, such as a translocation that could give a clue to the chromosomal location of a gene or genes involved in the etiology of Hodgkin's disease, has yet been found. Nevertheless it is clear that a number of nonrandom changes, including several that are also common in other malignancies including the non-Hodgkin's lymphomas, are frequently present, e.g., deletions of 1p, 6q, and 7q. Interestingly, deletions of 4q, with loss of 4q25 --> q27, that have also been reported may show some specificity for Hodgkin's disease.

Lack of BCL10 mutations in Hodgkin's disease-derived cell lines

The pathogenetic events leading to the malignant transformation of Hodgkin-Reed-Sternberg cells are unknown. As Hodgkin-Reed-Sternberg cells are resistant to CD95-mediated apoptosis and chromosomal aberrations involving the 1p22 region harbouring the proapoptotic BCL10 gene represent a recurrent event in Hodgkin's disease-derived cell lines, analysis of the BCL10 gene and its transcripts was performed. As transcription of wild-type BCL10 was detected in all Hodgkin's disease-derived cell lines analysed, alterations of the coding sequence of the BCL10 gene are unlikely to contribute to the malignant transformation of the Hodgkin-Reed-Sternberg cell.

Cytogenetics and molecular cytogenetics in Hodgkin's disease

For about 20 years we have known from cytogenetic studies that there is a clonal cell population in Hodgkin's disease. Most karyotypes are complexly aberrant and chromosome numbers typically lie in the hyperploid range. Some chromosome regions seem to be preferentially involved, but a chromosome aberration specific for Hodgkin's disease has not yet been determined. Although the existence of a clonal cell population is evident from these cytogenetic studies, there is still an ongoing debate, whether in all cases the pathognomonic Hodgkin and Reed-Sternberg cells belong to one single aberrant clone and thus represent a monoclonal proliferation. This article reviews the current knowledge on cytogenetics in Hodgkin's disease. Moreover, our recent data from simultaneous immunophenotyping and interphase cytogenetics (FICTION) are introduced into the passionate discussion on the monoclonality of the Hodgkin and Reed-Sternberg cells.

Hodgkin's Disease and Anaplastic Large Cell Lymphoma Revisited. 1. unique cytokine and cytokine receptor profile distinguished from that of non-hodgkin's lymphomas

In cultures, and in tissues as well, Hodgkin's and Reed-Sternberg (H-RS) cells and anaplastic large cell lymphoma (ALCL) cells are known to express a variety of cytokines, including IL-1, -5, -6, -8, -9, TNF-alpha, GM-CSF, M-CSF, TGF-beta, CD70, CD80, and CD86. Various numbers of H-RS/ALCL cells may express cytokine receptors (R), such as CD30, CD40, IL-2R (CD25/CD122), IL-6R (CD126), IL-7R (CD127), TNF-R (CD120), TGF-beta-R (CD 105/endoglin), M-CSF-R (CD115), and SCF-R (CD117/c-kit receptor). All of these cytokines and cytokine receptors are implicated in the growth regulation of H-RS/ALCL cells, the histopathologic alterations in tissues, and the clinical manifestations in patients with Hodgkin's disease (HD) or ALCL. Many of these cytokines or cytokine receptors also play an important role in the pathogenesis of other types of lymphomas. In this review, we describe the cytokine or cytokine-receptor expression that is diacritic for H-RS/ALCL cells. The identification of such unique cytokine-cytokine receptor interactions is likely to explain the biologic property that distinguishes HD/ALCL from other types of lymphomas. These interactions include those of CD30L-CD30, CD40L-CD40, CD70-CD27, CD80/CD86- CD28, SCF-CD117, IL-9-IL-9R, and IL-7-IL-7R. The H-RS/ALCL cells express IL-9 and two cytokine receptors, CD30 and CD117, which are observed infrequently in NHLs. Although IL-7 expression is not restricted to H-RS/ALCL cells, the expression of IL-7 in conjunction with IL-9 and/or CD117 may be regarded as unique for HD/ALCL because of an unusual combination and a synergistic activity among these cytokines. The expression of CD70 and CD80/CD86 (as cytokines) may exert a unique effect in HD because of intimate contact between H-RS cells and CD27/CD28-positive T cells. The expression of these costimulators (CD70 and CD80/CD86) and other adhesion/constimulator molecules such as CD54 and CD58, along with the secretion of soluble cytokines such as IL-1, IL-6, IL-7, or TNFs by H-RS/ALCL cells, could result in the profound T-cell proliferation often seen in lymph nodes involved by HD and some ALCL. On the other hand, the expression of CD30L and CD40L by surrounding T cells may affect the proliferation of H-RS/ALCL cells. The cytokine-cytokine receptor interaction between H-RS cells and T cells via direct cell-cell contact is bidirectional, a situation not commonly seen in NHLs. Copyright 1995 S. Karger AG, Basel

Large-cell anaplastic lymphoma-specific translocation (t[2;5] [p23;q35]) in Hodgkin's disease: indication of a common pathogenesis?

Chromosomal aberrations are characteristic and specific events; the detection of chromosomal abnormalities often provides information on diagnosis and prognosis of disease. Some patients with large-cell anaplastic lymphoma (Ki 1 lymphoma) have the translocation t(2;5) (p23; q35), involving a possible growth-regulating tyrosine kinase. We found this translocation in 11 patients with Hodgkin's disease of nodular sclerosis and mixed-cellularity types. This finding has implications for the understanding of the relation between large-cell anaplastic lymphoma and Hodgkin's disease, diseases with morphological and immunophenotypical similarities. Study of this translocation may help understanding of the origins of cancer and cancer growth. It also allows a more precise definition of Hodgkin's disease and may be used as an indicator for clonality--which has long been sought.

The Met/hepatocyte growth factor receptor (HGFR) gene is overexpressed in some cases of human leukemia and lymphoma

The proto-oncogene c-met encodes a heterodimeric (alpha, beta) tyrosine kinase receptor which binds the hepatocyte growth factor (HGF). Recently, overexpression of the Met/HGF receptor gene has been detected in fresh samples of carcinomas and in epithelial tumor cell lines but not in cell lines derived from human leukemia and lymphoma. Our analysis of 50 primary samples of human leukemia and lymphoma and 23 hematopoietic cell lines revealed expression of mRNA and protein of the met/HGF receptor in 6 out of the 73 hematopoietic tumor samples analyzed. Four of the six samples positive for expression of the Met/HGF receptor gene were derived from patients with Hodgkin's disease. In addition, in one Burkitt's lymphoma cell line and in one acute myeloid leukemia (AML), expression of the Met/HGF receptor gene was detected. In normal unstimulated lymphocytes, granulocytes or monocytes we did not find expression of the Met/HGF receptor gene. Upon stimulation with the phorbol ester TPA we detected a weak expression of Met/HGF receptor specific transcripts of 9.0 kb in peripheral blood mononuclear cells of a healthy donor. Cytogenetic analyses of three of the four cell lines which express the Met/HGF receptor gene revealed structural or numerical abnormalities of the long arm of chromosome 7, where the Met/HGFR gene is located, in each of the three cell lines analyzed. In one of these cell lines (L540) the Met/HGFR gene is translocated to a marker chromosome. Southern blot and pulsed field gel electrophoresis experiments did not show any rearrangement in a region of 600 kb around the Met/HGF receptor gene excluding an activation of Met/HGFR by a TPR/Met oncogenic rearrangement as described for MNNG-HOS cells and for some gastric tumors. Our data indicate that the Met/HGFR gene is deregulated in a few cases of human leukemia, Burkitt's lymphoma and Hodgkin's disease possibly by chromosomal rearrangements resulting in an overexpression of the normal Met/HGF receptor mRNA and protein without formation of a hybrid gene.

T-cell lymphoma developing in Hodgkin's disease: evidence for two clones

A case of peripheral T-cell lymphoma (PTL) occurring in a patient with Hodgkin's disease (HD) in relapse is described. The second neoplasm developed 25 months after the diagnosis of HD. Cytogenetic analysis on the lymph node biopsy at the time of diagnosis of PTL revealed the co-existence of two distinct, abnormal cell clones. The first clone was characterized by a reciprocal translocation t(5;7)(q13;q35) involving 7q35, namely the TCR-beta gene, as expected in T-cell lymphomas. The second cell clone carried trisomies for chromosomes 2, 5, 7, and 14. By immunophenotypic and molecular analysis as well as by in situ hybridization, it was possible to prove that the malignant T-cells and the Reed-Sternberg cells corresponded to different cell clones, one carrying the structural chromosome abnormalities and one carrying the numerical chromosome anomalies. These results indicate that the present case represented a true composite lymphoma.

Recent results on the biology of Hodgkin and Reed-Sternberg cells. II. Continuous cell lines

The relative scarcity of Hodgkin (H) and Reed-Sternberg (RS) cells within biopsies from cases with Hodgkin's disease (HD) is an impediment to the analysis of the nature and function of these cells. Continuous cell lines as uniform and permanently available sources of cells provide a valid alternative. Development of HD cell lines has proven to be rather difficult when compared with the results on leukemia and Non-Hodgkin lymphoma cells. Only a few cell lines containing cells that resemble in-vivo H-RS cells have been established. Because the in-vitro culture conditions favor the self-propagation of residual normal cells, e.g. Epstein-Barr virus transformed B-lymphoblastoid cells or monocyte/macrophage monolayers, early attempts at culturing HD tissue resulted mainly in the generation of such cell lines. Even for the bona fide HD cell lines it is difficult to prove that the immortalized cells originated from an H-RS cell. These 13 HD cell lines have been extensively characterized in a large variety of aspects. These data have resulted in widely varying conclusions about the nature of the cell lines. It is apparent that all HD cell lines are unique among hematopoietic cell lines and are also different from one another. No conclusive evidence towards the origin of the cells has been obtained for some cell lines, while others could be operationally, albeit not always unequivocally, assigned to the T- or B-cell or monocyte-macrophage lineages. The overall phenotypes are often not concordant with those of normal hematopoietic cells; some cell lines show clearly mixed lineage attributes. The artifactual expansion of non-HRS cells in culture and the acquisition or loss of certain properties during the adaptation to culture systems cannot be excluded. There was also a bias for the establishment of cell lines from cases with advanced clinical stages, nodular sclerosing subtype and pleural effusions. The extensive analysis of a few cell lines has provided a wealth of information useful for the understanding of the biology of H-RS cells. The striking heterogeneity could be reflective of a biologically heterogeneous disease.

Recent results on the biology of Hodgkin and Reed-Sternberg cells. I. Biopsy material

The most recent sophisticated investigations have provided new and revealing, but also contradictory and controversial information on the biological nature and the cellular origin of Hodgkin and Reed-Sternberg cells (H-RS). Immunophenotypic analyses have shown variable phenotypic antigen expression; but, on balance the data suggest a lymphoid cell expressing T- and/or B-cell-associated markers and certain activation antigens while lacking immunological features of monocytes-macrophages or other lineages. Molecular genetic studies have demonstrated heterogenous findings with respect to rearrangements of T-cell receptor and immunoglobulin genes. Only a small percentage of the cases has rearrangements; this might be due to the threshold of sensitivity of the method combined with the scarcity of the malignant cells. Epstein-Barr virus (EBV) genomes are clonally integrated in the H-RS cells of about half the cases. The significance of these findings--whether EBV is a causative agent or an epiphenomenon--remains to be elucidated. H-RS cells express mRNA and proteins of various cytokines and cytokine receptors implying a predominant role for cytokines in the pathophysiology of HD. The mononuclear and polynuclear H-RS cells are capable of DNA synthesis and nuclear division; the lack of cellular division leads to multinuclearity through the process of endomitosis. Mutations and expression of only a limited number of oncogenes have been tested thus far. Whether the bcl-2 oncogene is involved in HD remains a matter of debate. Aneuploidy and non-random chromosomal abnormalities are the results of cytogenetic analyses of H-RS cells. However, no chromosomal marker specific for HD has yet been found. Thus, while studies of EBV involvement, growth factor production, oncogene expression and chromosomal abnormalities contributed a fair amount of new data on the nature of H-RS cells, only immunophenotyping and genotyping provided some indication of the cellular derivation: an activated lymphoid cell that possibly expresses oncogenes, that probably is infected with EBV, that most likely produces cytokines, that certainly has multiple karyotypic abnormalities.

Recurring chromosome abnormalities in Hodgkin's disease

Cytogenetic analysis was performed on lymph nodes or other tumor masses from 33 patients with Hodgkin's disease. Metaphase cells were obtained in 25 of the 33 cases. Analyzable abnormal clones were found in nine cases. Characteristic abnormalities included polyploidy and complex structural rearrangements nonrandomly involving certain chromosomal regions. Chromosomes most commonly gained were 2, 9, 11, 19, and 20, and those most often lost were 10, 13, 15, 16, 21, and Y. Translocation breakpoints clustered in bands 1p11-1p13, 1p36, 4q35, 14q11, and 15p11. In five patients, breakpoints were in bands to which T-cell receptor genes have been mapped. No specific, recurring translocation was identified. There was, however, recurring loss of chromosomal material from 1q, 4q, 6q, and 17p. Loss or deletions of chromosomes 4 and 6 were found in five and six patients, respectively. Deletions overlapped; the smallest overlapping segments included bands 4q25-4q27 and 6q21-6q23. The data suggest that loss of specific chromosomal regions may be important in the pathogenesis of Hodgkin's disease. With respect to tumor specificity, deletions of 4q are of particular interest because these have not been previously reported to occur nonrandomly in other human malignancies.

Establishment of a new Hodgkin's cell line (HD-70) of B-cell origin

A new Hodgkin's cell line, designated HD-70, was established from the peripheral blood of a 69-year-old man with Hodgkin's disease of nodular sclerosing type. The cell line grows in a single cell suspension and has a doubling time of 28 hours. The cells have a round or irregular nucleus or multiple nuclei in relatively abundant cytoplasm that is positive for acid phosphatase, alpha-naphthyl butyrate esterase, and periodic acid-Schiff stains. HD-70 cells are positive for CD30 (Ki-1/Ber-H2), CD15 (Leu-M1), and CD71 (OKT9) antigens and contain cytoplasmic immunoglobulin (Ig) (A, kappa). Southern blot analysis showed that the cells have Ig heavy and kappa light chain gene rearrangement and lack T-cell receptor gene rearrangement. Chromosome analysis disclosed that the cells have a human karyotype with complicated abnormalities, including a 14q+. Heterotransplantation of the HD-70 cell line into newborn hamsters treated with antilymphocyte serum produced massive tumors with remarkable fibrosis and collagen band formation. These tumors displayed histologic features similar to those of the nodular sclerosing type tumor of the patient. Such fibrosis production and collagen band formation in heterotransplanted tumors suggest that a certain cytokine that induces fibrosis might be produced by HD-70 cells. This cell line may be useful for understanding the biology and pathogenesis of Hodgkin's disease.

An epidemiologist's view of the new molecular biology findings in Hodgkin's disease

Recent advances in molecular biology provide new strategies to address the pathogenesis of Hodgkin's disease (HD). Immunophenotyping studies of Reed-Sternberg cells suggest lymphoid cells, 'frozen in a state of activation.' Clonal rearrangement studies find heavy and light chain immunoglobulin and beta and gamma T-cell receptor gene changes. Chromosomal studies find a complex but nonrandom mixture of structural rearrangements including many seen in other hematologic disorders. These findings are consistent with a pathogenesis involving chronic antigenic stimulation. This interpretation is supported by the epidemiologic features of HD which suggest that HD may develop as a rare consequence of infection with a common latent virus where risk is increased if infection is delayed until adolescence or young adulthood. Such 'late' infections are generally more clinically severe and may result in more chronicity of virus replication. Serologic and genome probe studies of the Epstein-Barr virus--a candidate agent--in HD specimens support this hypothesis. In summary, the new molecular biology findings in HD converge with the previous epidemiologic, immunologic, and clinical data to support a unifying hypothesis of pathogenesis in which genetic abnormalities occur secondarily to a sustained host response to chronic tissue-based antigenic stimulation.

Karyotypic abnormalities and immunoglobulin gene rearrangements in Hodgkin's disease

Biopsy samples from seven patients with Hodgkin's disease (HD) were examined for cytogenetic abnormalities and rearrangement of the genes encoding the immunoglobulin chains and T-cell receptor chains. Three samples demonstrated clonal rearrangements of both IgH and IgL genes. No rearrangements of the TCR beta genes were detected in any of the samples. Karyotypic abnormalities were also found but only in the three cases where a clonal rearrangement of the immunoglobulin genes was shown. Two of these three cases had multiple karyotypic abnormalities, with the remaining patient being trisomic for chromosome 16 as the sole abnormality. These results are discussed and compared with previous reports in the literature concerning HD.

Heterogeneous expression of proto-oncogenes in Hodgkin's disease derived cell lines

The expression of 20 proto-oncogenes was analysed by Northern blotting in four cell lines derived from patients with Hodgkin's disease (L428, L540, CO and DEV) and compared to lymphoid and myeloid leukemia cell lines and normal hematopoietic cells. Expression of the proto-oncogenes c-myc, p53, c-jun, pim-1, lck, c-syn, c-raf and N-ras were detected in Hodgkin's disease derived cell lines and in normal hematopoietic cells. Transcripts of the proto-oncogene c-met were detected in the Hodgkin's derived cell lines L428 and L540 but not in the lymphoid or myeloid leukemia cell lines or in tonsil cells, peripheral blood mononuclear cells and granulocytes. Expression of the proto-oncogenes N-myc and lck were observed in the Hodgkin's derived cell line CO which express T cell receptor genes and in the T cell lines JM and CEM. L428 cells and CO cells expressed aberrant transcripts of the c-fes proto-oncogene. Thus Hodgkin's disease derived cell lines are heterogeneous in their expression pattern of proto-oncogenes, expressing normal and aberrant transcripts of proto-oncogenes which are not found in untransformed hematopoietic cells.

Cytogenetic and molecular genetic analysis of abnormal cells in Hodgkin's disease

Eleven tumors from ten patients with Hodgkin's diseases (HD) were characterized by histologic, cytogenetic, immunophenotypic, and genotypic studies. Cell surface markers for lymphocyte antigens did not show clonal excess. Five tumors showed the presence of karyotypically abnormal cells, but no common abnormalities were found. The remaining six tumors showed normal karyotypes. Ten tumors were analyzed for gene rearrangements with probes for IgJH, IgCk. IgC lambda, and TCR-beta genes. The IgJH probe detected a minor clonal population (about 5%) in one tumor with abnormal karyotype; three tumors with abnormal karyotypes showed germline genotype. In contrast, four of the six tumors with normal karyotypes showed rearrangements in IgJH (one tumor) and in C-lambda (three tumors) genes. The pattern of gene rearrangement observed in these tumors did not obey the hierarchy described in B-cell differentiation. These results suggest that B-cell lineage cannot be attributed unequivocally to the clonal populations in HD.

Cytogenetic studies of Hodgkin's disease. Analysis of involved lymph nodes from 12 patients

Cytogenetic studies were performed on 12 involved lymph nodes from Hodgkin's disease patients utilizing conditioned medium from 12-O-tetradecanoylphorbol-13-acetate-staphylococcus enterotoxin A induced mononuclear cells. The majority of cells analyzed had a normal karyotype. An unusually high rate of nonclonal karyotypic abnormalities was noted in most cultures. Clonal abnormalities involving chromosomes 3 and 21 were noted in two patients. Cytogenetic analysis of cultures stimulated with conditioned medium or specific growth factors may lead to a better understanding of the genetic mechanisms involved in Hodgkin's disease.

A marker and putative pathoantigen of Hodgkin's cells

A galactose-specific lectin, recently described by our laboratory, is immunologically demonstrable on the surface of neoplastic cells derived from patients with Hodgkin's disease. This Hodgkin's lectin is shown to be functionally and antigenically related to the galactose-N-acetylgalactosamine-specific lectin of the hepatocyte (HBP). Poly- and monoclonal antibodies against either the cytoplasmic tail or the cell-surface binding site of HBP recognize the Hodgkin's lectin as a 55 Kd protein. Expression of the 55 Kd antigen appears to be restricted to Hodgkin's disease involved tissues and cells of the monocyte/macrophage lineage. The putative identification of the Hodgkin's lectin as an ectosialyltransferase unique to Hodgkin's cells is supported by inhibition of enzymatic activity by anti-HBP antibodies. Cultured Hodgkin's cells, in analogy to purified HBP, agglutinate T-lymphocytes mediated by the Hodgkin's lectin. This cell-to-cell interaction results in the incorporation of sialic acid into lymphocyte surface asialoglycans as well as in the stimulation of lymphocyte proliferation. The function of the Hodgkin's lectin as lymphocyte agglutinant in vitro suggests its role as an immunomodulator contributing to the immunodeficiencies associated with Hodgkin's disease.

L-428 Reed-Sternberg cells and mononuclear Hodgkin's cells arise from a single cloned mononuclear cell

The L-428 cell line derived from nodular sclerosing Hodgkin's disease was verified to be a human female cell line with surface marker and morphologic characteristics similar to native Hodgkin's cells. Single cells were cloned and subcloned twice to determine the characteristics of the clonogenic L-428 Hodgkin's cell (resulting in a 10% cloning efficiency). Both mononuclear L-428 cells and classical Reed-Sternberg cells arose from solitary cells. The clonogenic cell was the mononuclear Hodgkin's cell, although small abortive colonies sometimes arose from classical binucleate Reed-Sternberg cells. Cytogenetic and phenotypic analysis supported the clonality of three subclones and indicated, among many findings, consistent abnormalities of the long arm of chromosome 7 (beta-chain of the T cell receptor) and 14q32 (Ig heavy chain). Distinctive abnormalities of cytogenetics, phenotyping and transforming growth factor-beta production were exhibited for each clone as well. These observations demonstrate the relationship of the continuum of malignant mononuclear and multinuclear Reed-Sternberg cells in this cell culture from nodular sclerosing Hodgkin's disease and suggest that a similar relationship exists in native Hodgkin's disease tissue. These observations also support the theory of clonality in Hodgkin's disease and suggest that in vivo contiguous metastasis in the L-428 Hodgkin's disease patient was most likely accomplished by a Ki-1 positive small mononuclear cell.

A review and interpretation of cytogenetic abnormalities identified in Hodgkin's disease

The nature of the cell which gives origin to Hodgkin's disease remains unclear after years of intensive investigation. Cytogenetic data, which are very scarce in Hodgkin's disease, could contribute information which might help elucidate this problem. Review of our own data and others shows that the most frequent abnormalities in this disorder involve chromosomes 14q in 35 per cent of cases, 11q in 32 per cent, 6q in 32 per cent, and 8q in 18 per cent. The most common breakpoint in chromosome 14 occurred at 14q32 where the IgH chain genes reside thus suggesting that in these cases the cell of origin might be a B lymphocyte. The 11q and 6q structural abnormality have also been frequently seen in lymphoid disorders such as ALL and large cell lymphoma. Of interest also is the fact that in a certain type of childhood pre-B cell acute lymphoblastic leukemia which shows cytogenetic abnormalities on 11q23, aberrant myeloid and monocytic markers are seen. This suggests that in Hodgkin's disease a similar phenomenon might occur which could help to explain why the Reed-Sternberg cell expresses myeloid-monocytic antigens such as Leu M-1.

Chromosome abnormalities in peripheral blood lymphocytes from untreated Hodgkin's patients. A possible evidence for chromosome instability

We describe the presence of a high frequency of spontaneous chromosome aberrations in lymphocytes from six untreated patients with Hodgkin's disease. The characteristics of the chromosome abnormalities observed suggest the existence of a certain degree of chromosome instability in these cases, that could be a predisposing factor for the development of malignancies.

Cytogenetic studies in Hodgkin's disease

Cytogenetic analysis was attempted in 20 patients with Hodgkin's disease. No mitoses were found in 2 cases, normal metaphases in 7, and normal metaphases with nonclonal aberrations in 7. Of the 4 cases with clonal aberrations, one had +16 as the sole change, whereas the remaining tumors had multiple numerical and structural changes.

Phenotype versus immunoglobulin and T-cell receptor genotype of Hodgkin-derived cell lines: activation of immature lymphoid cells in Hodgkin's disease

Three Hodgkin-derived cell lines (L428, L540, and CO) were studied for rearrangements and expression of immunoglobulin and T-cell receptor genes, and their genotype was compared to the phenotype. As far as the genotype is concerned, all 3 cell lines have characteristics of lymphoid cells; L428 of B, and L540 and CO of T-cell origin. L428 cells have one Ig heavy chain allele rearranged to C gamma and transcribed into RNA, while the second is deleted. Furthermore, L428 cells show an unusual immunoglobulin kappa light chain gene rearrangement involving deletion of the kappa constant gene in one allele, while the remaining kappa and lambda loci are in germline configuration. L540 and CO have, in contrast to L428 cells, the immunoglobulin genes in germline and T-cell receptor genes rearranged. The T-cell receptor beta and gamma genes are rearranged in both L540 and CO, whereas a rearrangement in the alpha locus was detected in L540 cells only. RNA of the size of functional beta chain transcripts was found in CO cells and of the size of functional alpha chain transcripts in L540 cells. All 3 cell lines are classified as immature lymphoid cells with respect to the limited expression of B- and T-cell antigens, respectively, and to the incomplete expression of their antigen receptor. The immaturity of lymphoid differentiation contrasts with the expression of activation antigens, i.e. Ki-1, Ki-24, HLA-DR, and IL-2 receptor. The immaturity of the cells excludes the possibility that the cells were activated along the physiological pathway, i.e. by interaction of the cell with antigen. The results obtained on the cell lines are in accordance with in vivo studies and suggest that Hodgkin and Sternberg-Reed cells are immature lymphoid cells which are activated by a still unknown mechanism.