Clonal cytogenetic abnormalities in Hodgkin's disease

Establishment of the TALE-code reveals aberrantly activated homeobox gene PBX1 in Hodgkin lymphoma

Homeobox genes encode transcription factors which regulate basic processes in development and cell differentiation and are grouped into classes and subclasses according to sequence similarities. Here, we analyzed the activities of the 20 members strong TALE homeobox gene class in early hematopoiesis and in lymphopoiesis including developing and mature B-cells, T-cells, natural killer (NK)-cells and innate lymphoid cells (ILC). The resultant expression pattern comprised eleven genes and which we termed TALE-code enables discrimination of normal and aberrant activities of TALE homeobox genes in lymphoid malignancies. Subsequent expression analysis of TALE homeobox genes in public datasets of Hodgkin lymphoma (HL) patients revealed overexpression of IRX3, IRX4, MEIS1, MEIS3, PBX1, PBX4 and TGIF1. As paradigm we focused on PBX1 which was deregulated in about 17% HL patients. Normal PBX1 expression was restricted to hematopoietic stem cells and progenitors of T-cells and ILCs but absent in B-cells, reflecting its roles in stemness and early differentiation. HL cell line SUP-HD1 expressed enhanced PBX1 levels and served as an in vitro model to identify upstream regulators and downstream targets in this malignancy. Genomic studies of this cell line therein showed a gain of the PBX1 locus at 1q23 which may underlie its aberrant expression. Comparative expression profiling analyses of HL patients and cell lines followed by knockdown experiments revealed NFIB and TLX2 as target genes activated by PBX1. HOX proteins operate as cofactors of PBX1. Accordingly, our data showed that HOXB9 overexpressed in HL coactivated TLX2 but not NFIB while activating TNFRSF9 without PBX1. Further downstream analyses showed that TLX2 activated TBX15 which operated anti-apoptotically. Taken together, we discovered a lymphoid TALE-code and identified an aberrant network around deregulated TALE homeobox gene PBX1 which may disturb B-cell differentiation in HL by reactivation of progenitor-specific genes. These findings may provide the framework for future studies to exploit possible vulnerabilities of malignant cells in therapeutic scenarios.

Investigation of miR9-1, miR9-2 and miR9-3 Methylation in Hodgkin Lymphoma

BACKGROUND

miR9 is an important tumor suppressor microRNA regulated by DNA methylation in various types of cancers.

METHODS

We analyzed the methylation status of the 3 members of the miR9 family in 58 cases of Hodgkin lymphoma (HL) in comparison to 15 reactive lymph nodes. We also assessed the relationships between miR9 methylation and Epstein-Barr virus (EBV) infection and several clinicopathological parameters.

RESULTS

We found that 84.5% of HL cases had a methylation in at least 1 of the 3 loci of miR9, whereas none of the nontumoral samples was methylated. The highest rate of methylation was found in miR9-2 (5q14.3) in 74.1% of the HL cases, followed by miR9-3 (15q26.1) in 56.9% and miR9-1 (1q22) in only 8.6% (p < 0.001). The promoter methylation of miR9-3 was more frequent in patients older than 15 years than in children (p = 0.02) and among women rather than men (p = 0.02). However, no significant correlation was found between miR9 methylation and EBV infection.

CONCLUSION

These results indicate that miR9 methylation, especially miR9-2, is a frequent event in HL and may be involved in HL pathogenesis, irrespective of EBV infection.

A case of Hodgkin's lymphoma with severely impaired liver function treated successfully with gemcitabine followed by ABVD

Hodgkin’s lymphoma (HL) originates from clonal B cells and is the most common malignancy in the second decade of life. Liver involvement is uncommon at presentation in patients with HL and there is a paucity of data for treatment of patients with severely impaired liver function. We present an unusual case of HL with severe hepatic impairment, splenomegaly and multiple chromosomal abnormalities that was treated initially with gemcitabine and steroids. Once liver function tests improved, six cycles of Adriamycin, bleomycin, vinblastine, and dacarbazine were administered. The patient remains in remission at 3.5 years of follow-up.

Differential Expression Patterns of c-REL Protein in Classic and Nodular Lymphocyte Predominant Hodgkin Lymphoma

Classic Hodgkin lymphoma (cHL) is characterized by numerical gains of the short arm of chromosome 2. The high frequency of 2p overrepresentation including REL, particularly in the nodular sclerosis subtype suggests that constitutive activation of nuclear factor kappaB/REL is a hallmark of Reed-Sternberg (RS) cells. The aim of this study was to investigate c-Rel protein expression patterns in cHL and nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) cases by immunohistochemical analysis. A total of 79 cases of HL were analyzed, which included 59 cases of cHL (49 nodular sclerosis; 8 mixed cellularity; 2 lymphocyte-rich) and 20 cases of NLPHL. Positive staining was defined in this study as a reaction seen in the nuclei or nuclei and cytoplasm of RS or lymphocytic and histiocytic (L&H) cells in cHL and NLPHL cases, respectively. The percent positivity of c-REL staining of RS cells in cHL was seen in 51 of 59 cases (86.4%). No significant difference in c-REL expression was seen between nodular sclerosis (42 of 49, 85.7%) and mixed cellularity subtypes (7 of 8 cases, 87.5%; P = 1). In comparison, positive c-REL protein expression in L&H cells was seen in 5 of 20 NLPHL cases (25.0%). Therefore, significantly higher positivity of RS cells in cHL was seen compared with positivity of L&H cells in NLPHL; 86.4% vs. 25.0%; P = 0). Expression of Epstein-Barr virus latent membrane protein was seen in 6 of 30 cases (19.0%; 25 cHL, 5 NLPHL) and EBER1 in 5 of 27 cases (18.5%; 24 cHL, 3 NLPHL). The presence of Epstein-Barr virus did not correlate with c-REL protein expression (P = 1). Our results demonstrate that there is differential c-REL protein expression in cHL in comparison with NLPHL and suggest that c-REL may play a role in the pathogenesis of classic Hodgkin lymphoma.

Acquired Robertsonian translocations are not rare events in acute leukemia and lymphoma

Robertsonian translocations are the most common constitutional structural abnormalities but are rarely reported as acquired aberrations in hematologic malignancies. The nonhomologous acrocentric rearrangements are designated as Robertsonian translocations, whereas the homologous acrocentric rearrangements are referred to as isochromosomes. Robertsonian rearrangements have the highest mutation rates of structural chromosome rearrangements based on surveys of newborns and spontaneous abortions. It would be expected that Robertsonian recombinations would be more common than suggested by the literature. A survey of the cytogenetics database from a single institution found 17 patients with acquired Robertsonian rearrangement and hematologic malignancies. This is combined with data from the literature for a total of 237 patients. All of the possible types of Robertsonian rearrangements have been reported in hematologic malignancies, with the i(13q), i(14q), and i(21q) accounting for nearly 60%. Complex karyotypic changes are seen in the majority of cases, corresponding with disease evolution. These karyotypes consistently show loss of chromosomes 5 and/or 7 in the myelocytic disorders, nonacrocentric isochromosomes, and centromeric breakage and reunion. However, nearly 25% of the acquired rearrangements were found as the sole abnormality or in addition to an established cytogenetic aberration. Most of these were the i(14q) with the myelodysplasia subtypes refractory anemia and chronic myelomonocytic leukemia.

Baseline and treatment-induced chromosomal abnormalities in peripheral blood lymphocytes of Hodgkin's lymphoma patients

PURPOSE

To study chromosomal abnormalities in 49 patients with Hodgkin's lymphoma (HL), before and after treatment and at several times during a 2-year period.

METHODS AND MATERIALS

Simple chromosomal aberrations (CAs) and complex chromosomal rearrangements (CCRs) were counted in peripheral lymphocytes by painting of chromosomes 1, 3, and 4 (fluorescence in situ hybridization). A control population was composed of 20 healthy donors and 69 untreated cancer patients who had undergone various radiologic scans.

RESULTS

A greater frequency (p < 10(-4)) of spontaneous cytogenetic abnormalities was observed in untreated HL patients compared with the control populations. CCRs were observed exclusively in the HL population (p < 10(-4)). Chemotherapy was associated with a significant increase in the frequency of CAs (p < 10(-4)), according to the chemotherapy regimen (p = 0.002). Immediately after radiotherapy, a significant increase (p < 10(-4)) was observed in CAs according to the size of the irradiation field. Conversely, the significant increases in the frequency of CCRs observed after treatment did not correlate with the chemotherapy regimens, radiotherapy dose, or size of the irradiation field. The evolution of CAs vs. CCRs over time was also dissociated: during the follow-up of these patients, a significant decrease was observed in the frequency of CAs at 6 months and 1 and 2 years. In contrast, after an initial decrease for up to 6 months after treatment, the frequency of CCRs remained constant for up to 2 years.

CONCLUSION

Increased cytogenetic abnormalities were observed in untreated HL patients compared with the control populations. The greater frequency of cytogenetic abnormalities persisted in some patients. The presence of CCRs supports the concept of a unique genetic environment in HL patients that persists in response to potentially noxious treatments.

The Reed-Sternberg cell in classical Hodgkin's disease

There has been substantial advances in our understanding of the nature of the Hodgkin/Reed-Sternberg (H/RS) cell in recent years. There is now compelling evidence that the H/RS cells in the vast majority of cases of classical Hodgkin's disease (CHD) are derived from the B-cell lineage and a major clonal population is present. The immunoglobulin heavy chain variable region gene generally has a high load of somatic mutations suggesting that the H/RS cells are derived from germinal center (GC) (GC) or post-GC cells. The cellular milieu in the tumour is largely determined by the cytokines and chemokines secreted by the H/RS cells and the surrounding reactive elements. The pattern of secretion is partially determined by signals transduced through direct surface interactions between H/RS cells and infiltrating T-cells. Immunosuppressive cytokines and cytokines that preferentially induce a TH2 type of immune response may be partially responsible for the escape of the H/RS cells from immune surveillance. Multiple genes that have been shown to be involved in neoplastic transformation have been studied in HD. The significance of the data generated has been difficult to interpret. Efforts have been made to study the global gene expression pattern of the H/RS cells. There are many difficulties inherent in this approach, but new insight into the pathogenesis and evolution of HD would be expected from the studies.

Karyotypic dissection of Hodgkin's disease cell lines reveals ectopic subtelomeres and ribosomal DNA at sites of multiple jumping translocations and genomic amplification

Although the neoplastic significance of the chromosome changes widespread in Hodgkin's disease (HD) remains obscure, a distinct cytogenetic picture has emerged combining aneuploidy with structural rearrangements clustered at certain breakpoints. Notably absent are the recurrent chromosome translocations which distinguish other hematopoietic neoplasms and serve as clues to underlying oncogene alterations. The paucity of neoplastic cells in HD biopsies hinders detailed chromosome analysis. As an alternative, we investigated a panel of well characterized cell lines by classical and molecular cytogenetics, using single-gene and subtelomeric probes, including three autologous HD examples (HDLM-1/2/3) analyzed by 'spectral karyotyping' - the first complete HD karyotype to be documented. Although complex, most rearrangements in HDLM cells arose in vivo and included few rare but many typical HD breakpoints, notably at the r(ibosomal)DNA regions. Two types of genomic rearrangement involving DNA repeats were conspicuous: insertion and genomic amplification/coamplification of rDNA-the first genomic rDNA rearrangements to be reported in a tumor cell, and the first example of multiple 'jumping translocations' (JT). Of four subtelomeric microsatellite repeats tested in HDLM cells, three exhibited interstitial sites at JT, of which two (at 5qter and 9pter) were respectively associated with deletion of the 5q31-32 myeloid region, and coamplification of a recently described HD-recurrent amplicon at 9p2 together with transcriptionally silent rDNA. Altogether, three out of four HD cell lines carried interstitial 9p subtelomeres and rDNA rearrangements. Taken together, these data suggest tumorigenic rearrangements may be facilitated by 'hitchhiking' along with mobile DNA repeat sequences which may target gene rearrangement at 9p in HD. Southern analysis of parallel rearrangements within rDNA intergenic spacers in HDLM cells highlighted several at, or near, retroposons. As well as validating HD cell lines as cytogenetic models, and resources for identifying genes rearranged in HD, our findings warrant further investigation of the roles of DNA repeat sequences, notably subtelomeric microsatellites, rDNA spacer sequences and retroposons as facilitators and markers of tumor-gene rearrangement.

Mapping of a minimal deleted region in human hepatocellular carcinoma to 1p36.13-p36.23 and mutational analysis of the RIZ (PRDM2) gene localized to the region

Human chromosome band 1p36 commonly undergoes loss of heterozygosity (LOH) in hepatocellular carcinoma (HCC) but the minimal deleted region remains to be mapped. This chromosomal region contains a candidate HCC suppressor gene, RIZ (PRDM2), that is a member of the PR (PRDI-BF1-RIZ homology)-domain-containing zinc finger gene family. One characteristic of this family is the unusual yin-yang involvement in human cancers. The PR-domain-containing RIZ1 product of the RIZ locus, in contrast to the PR-domain-minus product RIZ2, is commonly lost or underexpressed in HCC. Furthermore, RIZ1 can induce cell cycle arrest, apoptosis, or both and suppress HCC tumorigenicity in nude mice. To help identify the putative HCC locus on 1p36 and to evaluate a genetic role of RIZ in HCC, we studied 97 HCC cases and mapped a minimal deleted region in HCC to 1p36.13-p36. 23 between markers D1S434 and D1S436. Notably, RIZ mapped within this region and was found to undergo LOH in 37% (25/67) of HCC cases. Single-strand conformation polymorphism (SSCP) analysis, however, did not show mutations in the PR-domain region of RIZ1 in 49 cases of HCC examined. Our data suggest that the RIZ locus is a target of frequent deletion in HCC, but that the more common way of RIZ inactivation in HCC may not involve mutations that alter peptide sequences. Genes Chromosomes Cancer 28:269-275, 2000.

Pathobiology of NPM-ALK and variant fusion genes in anaplastic large cell lymphoma and other lymphomas

Despite its clinical and histological heterogeneity, anaplastic large cell lymphoma (ALCL) is now a well-recognized clinicopathological entity accounting for 2% of all adult non-Hodgkin's lymphomas (NHL) and about 13% of pediatric NHL. Immunophenotypically, ALCL are of T cell (predominantly) or Null cell type; by definition, cases expressing B cell antigens are officially not included in this entity. The translocation (2;5)(p23;q35) is a recurring abnormality in ALCL; 46% of the ALCL patients bear this signature translocation. This translocation creates a fusion gene composed of nucleophosmin (NPM) and a novel receptor tyrosine kinase gene, named anaplastic lymphoma kinase (ALK). The NPM-ALK chimeric gene encodes a constitutively activated tyrosine kinase that has been shown to be a potent oncogene. The exact pathogenetic mechanisms leading to lymphomagenesis remain elusive; however, the synopsis of evidence obtained to date provides an outline of likely scenarios. Several t(2;5) variants have been described; in some instances, the breakpoints have been cloned and the genes forming a new fusion gene with ALK have been identified: ATIC-ALK, TFG-ALK and TPM3-ALK. Cloning the translocation breakpoint and identifying the ALK and NPM genes provided tools for screening material from patients with ALCL using various approaches at the chromosome, DNA, RNA, or protein level: positive signals in the reverse transcriptase-polymerase chain reaction (RT-PCR) and the immunostaining with anti-ALK monoclonal antibodies (McAb) serve as the most convenient tests for detection of the t(2;5) NPM-ALK since the fusion gene and ALK protein expression do not occur in normal or reactive lymphoid tissue. The wide range of NPM-ALK positivity reported in different series appears to be dependent on the inclusion and selection criteria of the ALCL cases studied. Overall, however, 43% of ALCL cases were NPM-ALK+ (83% of pediatric ALCL vs 31% of adult ALCL). Occasional non-ALCL B cell lymphomas (4%) with diffuse large cell and immunoblastic histology and Hodgkin's disease cases (3%) were NPM-ALK-, but these data are questionable. The aggregate results indicate that, in contrast to primary nodal (systemic) ALCL, the t(2;5) may be present in only 10-20% of primary cutaneous ALCL and rarely, if at all, in lymphomatoid papulosis, a potential precursor lesion; however, these 10-20% positive cases were not confirmed by anti-ALK McAb immunostaining and may represent an overestimate. Positivity for NPM-ALK is associated to various degrees with the following parameters: 44% and 45% of ALCL cases with T cell and Null cell immunophenotype, respectively, are positive, whereas only 8% of cases with a B cell immunoprofile are positive; the mean age of positive patients is significantly younger than that of negative patients; positive cases carry a better overall prognosis (but not in all studies). Recently, the homogenous category of ALK lymphoma ('ALKoma') has emerged as a distinct pathological entity within the heterogenous group of ALCL. The fact that patients with ALK lymphomas experience significantly better overall survival than ALK- ALCL demonstrates further that analysis of ALK expression has important prognostic implications. The term ALK lymphoma signifies a switch in the use of the diagnostic criteria: cases are selected on the basis of a genetic abnormality (the ALK rearrangement), instead of the review of morphological or immunophenotypical features which are clearly more prone to disagreement and controversy. Since its initial description in 1985 ALCL has become one of the best characterized lymphoma entities.

A case of chronic lymphocytic leukemia with a constitutional pericentric inversion of chromosome 1

Chronic lymphocytic leukemia (CLL) has been reported to be associated with various chromosomal aberrations, the most common being trisomy 12 and structural rearrangements involving 13q, 11q, and 17p. We present a case of CLL with a constitutional pericentric inversion of chromosome 1.

Integrated high-resolution BAC, P1, and transcript map of the CHH region in chromosome 9p13

A bacterial artificial chromosome (BAC) and P1 contig of the proximal part of chromosome 9p centromeric of markers D9S165 and D9S304 is described. This 1.1- to 1.7-Mb portion of chromosome 9p13 was previously not physically mapped. It contains 24 genes or expressed sequence tags, five polymorphic AC repeats, and three new polymorphic single-strand conformation polymorphism variants. Several of the genes thus mapped are excellent candidates for disease-causing genes whose loci have previously been assigned to proximal 9p. Our primary interest is in the cartilage-hair hypoplasia gene (CHH) that resides within the contig between markers D9S163 and D9S1791 based on linkage evidence.

Chromosome aberrations in adult Hodgkin disease in a Danish population-based study

During a 6-year period, 31 patients with Hodgkin disease (HD) were analyzed for chromosome aberrations on lymphoid tissue. We obtained metaphases in 87% (27/31). The number of cells analyzed per case ranged from 17 to 31 (median 25), and the number of abnormal mitoses was between 1 and 17 (median 6). Chromosome aberrations were found in 59% (16/27). Numerical aberrations involved all chromosomes. The most frequently gained chromosomes were numbers 2 and 9, and the most frequently lost were numbers 10, 16, 21, 22, and X. Chromosomes most frequently involved in structural aberrations were numbers 1 and 6. The most frequent subgroups were nodular sclerosis (NS) (n = 16) and mixed cellularity (MC) (n = 10). Six NS patients and 8 patients with MC showed an abnormal clone. For the NS patients with an abnormal karyotype, 4 of 6 had a gain of chromosome 2, and all had structural aberrations of chromosome 1. Of the 6 MC patients, where a partial analysis was possible, 4 had a gain of chromosome 9, 2 had structural aberrations involving chromosome 6 and 2 of chromosome 14. In 1 case a translocation normally associated with non-Hodgkin lymphoma (NHL) was found (t[11;14]), whereas other translocations characteristic of NHL, such as t(8;14), t(14;18), and t(2;5) were not observed. A review of the literature on cytogenetic investigations in HD performed on lymphoid tissue showed that the most frequently gained or lost chromosomes were 1, 2, 5, 9, and 12 for NS and 2, 5, and 9 for MC. The most frequently affected chromosomes in structural aberrations were 1 and 6 for NS, and 1, 7, and 14 for MC. Involvement of chromosome 1, 6, and 14 in structural aberrations is characteristic of lymphoid neoplasms, as are the most frequently involved bands (1p36, 6q21-q26, 14q11, and 14q32) further supporting a B- or T-cell origin of the neoplastic cell in HD. The high hyperploidy seen in HD is not a frequent observation in NHL. Although certain chromosome aberrations seem to be characteristic of HD as opposed to NHL, specific nonrandom aberrations have yet to be identified. The rather low number of abnormal mitoses found in most HD cases underlies the importance of analyzing a large number of metaphases.

Chromosomal abnormalities in Hodgkin's disease are not restricted to Hodgkin/Reed-Sternberg cells

Hodgkin and Reed-Sternberg cells are considered to represent the malignant fraction in Hodgkin's disease. Several studies have shown that the Hodgkin and Reed-Sternberg cells are chromosomally abnormal, but genetic data about the morphologically normal cell population in Hodgkin's disease are very limited. This latter cell population has therefore been examined for chromosomal aberrations, using the in situ hybridization (ISH) procedure, making use of DNA probes for chromosomes 1, 7, 8, 9, 11, 12, 15, 17, and 18. Nuclei were isolated from freshly frozen (10 cases) and paraffin-embedded (16 cases) biopsy samples and 1000 nuclei per case were evaluated. The cases of Hodgkin's disease were compared with reactive lymph nodes, which show aberrant chromosome copy numbers in less than 1 per cent of the cells. Using strict scoring criteria, nuclei in the tumour were found to show an abnormal genotype, in the range of 1-12 per cent, with trisomies occurring most frequently. No characteristic numerical chromosome abnormality was observed. ISH on 4 microns thick paraffin sections of six cases of Hodgkin's disease revealed numerical aberrations for chromosome 1 in cells which appeared to be morphologically normal. The genomically abnormal nuclei did not differ in morphology or size from the nuclei of morphologically normal cells, but differed considerably in size when compared with the nuclei of Hodgkin/Reed-Sternberg cells after the ISH procedure. Three of these six cases revealed a population of apparently normal cells with an aberrant copy number which differed notably from the fraction observed in reactive lymph nodes. It is concluded, therefore, that a subset of morphologically normal cells, next to the Hodgkin/Reed-Sternberg cells, are chromosomally aberrant and may participate in the malignant cell fraction of Hodgkin's disease.

Numerical chromosomal aberrations in Hodgkin's disease detected by in situ hybridisation on routine paraffin sections

AIMS

To visualise directly numerical chromosomal aberrations and polyploidy in both Hodgkin and Reed Sternberg (HRS) cells and background cells from cases of Hodgkin's disease using in situ hybridisation.

METHODS

Non-isotopic DNA in situ hybridisation was applied to interphase cell nuclei of Hodgkin's disease within routine paraffin embedded tissue sections. Two a satellite DNA probes, specific for chromosomes 3 and 12, were used to evaluate the feasibility of this approach. Double labelling with immunocytochemical detection of the CD30 antigen was used to identify HRS cells. Cytogenetic normal diploid and triploid placental tissue served as controls.

RESULTS

The eight cases of Hodgkin's disease investigated displayed frequent polysomy, while the majority of background cells showed disomy signals.

CONCLUSIONS

Numerical chromosomal aberrations were detected in HRS cells from eight cases of Hodgkin's disease by in situ hybridisation. These data show that in Hodgkin's disease HRS cells frequently display polyploidy compared with background cells and are, therefore, probably the only neoplastic component in this disease. Correlations between polysomy and tumour type or grade could not be made from these data owing to the limited number of cases examined and to problems with interpreting data from truncated nuclei.

Detection of numerical karyotype changes in the giant cells of Hodgkin's lymphomas by a combination of FISH and immunohistochemistry applied to paraffin sections

Conventional karyotyping of Hodgkin's disease (HD) has until now yielded only limited insight into karyotypic characteristics of this disease. For this reason, fluorescence in situ hybridization (FISH) using alpha-satellite chromosome-specific probes was applied to paraffin sections of HD tumors in order to verify numerical aberrations suggested to be specific for HD in the literature. The FISH technique was combined with immunohistochemical detection of the CD30 antigen to allow easier identification of the Reed-Sternberg and Hodgkin (RS&H) cells. The number of specific FISH signals per nucleus was determined both in CD30-positive RS&H cells as well as in non-malignant "bystander" cells in order to assess differences in the signal distribution. Contrasted with normal lymphoid cells, the tumor cells in HD were found to be polysomic for at least one of the chromosomes analyzed (1,2,4, and 8). The technique described is a reliable method for confirmation of results obtained from conventional cytogenetics, which is especially suited for archival material or samples not containing dividing cells.

A human SHC-related sequence maps to chromosome 17, the SHC gene maps to chromosome 1

The SHC gene encodes a protein that is thought to act as an adapter in many signal transduction pathways; the SHC protein probably facilitates the activation of RAS proteins in response to a variety of factors. We have mapped the human SHC gene and have identified a new SHC-related sequence. We have sequenced the region corresponding to the SHC 3' UTR from both loci and have mapped cosmids by fluorescence in situ hybridization. The human SHC gene maps to the proximal long arm of chromosome 1 and the SHC-related sequence maps to the proximal long arm of chromosome 17. A number of cancers have been positioned in the proximal long arm of chromosome 1; this is of interest given the oncogenic potential of the SHC protein.

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.

Giant cell formation in Hodgkin's disease

The identity of Reed-Sternberg cells in Hodgkin's disease has remained an unresolved issue, though many studies have addressed this question. Giant cells are usually formed either by endomitosis without cytoplasmic division or by cell fusion through cytokines or viruses. Growing evidence associates Epstein-Barr virus (EBV) with Hodgkin's disease, a major issue being whether EBV is a passenger virus or has an aetiological role. This communication describes experimental conditions enabling observation of giant cell cytogenesis from peripheral blood mononuclear cells in culture. Mononuclear cells were isolated from autologous peripheral blood and cocultured with a single-cell suspension obtained from Hodgkin's lymph nodes in a culture chamber where the two cell populations are isolated by a microporous membrane that allows only cytokines and viruses to pass through. Under these experimental conditions, giant cells are formed in the peripheral blood mononuclear cell fraction; some of them appear morphologically indistinguishable from Reed-Sternberg cells and their mononuclear variant, while others much resemble Langhans giant cells. Some of these giant cells are positive for EBV DNA by in situ hybridization. These results suggest that an EBV-dependent biological activity is responsible for giant cell cytogenesis originating from lymphocytes and monocytes, induced either by EBV and/or cytokines.

Phenotypic and genotypic characterization of Hodgkin's disease

Although a few studies have reported clonal cytogenetic changes in Hodgkin's disease (HD), their correlation with histologic groups is poorly defined. This is because of insufficient numbers of clonally abnormal cases ascertained in each of these studies, an inherent problem associated with the cytogenetic studies of HD. In this report we present results of pathologic, phenotypic, and genetic studies on 29 HD tumors consecutively ascertained by us and the results of a comprehensive analysis of the cytogenetic data available in the literature. In our series 75% of the tumors were positive for Epstein-Barr virus (EBV) by polymerase chain reaction (PCR) assay. A higher frequency of EBV-positive tumors showed clonal karyotypic abnormalities than the EBV-negative tumors. Unlike the case in the previous reports, none of the 24 tumors studied by PCR showed the presence of t(14;18) (q32;q21)-carrying cells. From the comprehensive analysis of the literature, we identified recurring nonrandom numerical changes, deletions, and chromosome breaks in HD. Some of these are associated either with nodular sclerosis or with mixed cellular histologies. A comparison of the pattern of these nonrandom cytogenetic changes in HD and those reported for non-Hodgkin's lymphomas (NHL) identified common deletions and breaks between them. These common genetic lesions probably play a role in disease evolution.

P53 protein expression in Hodgkin's disease

P53 is an oncosuppressor gene which is located on chromosome 17. Mutations of the p53 gene are closely associated with malignant transformation under in vitro conditions and are the most common genetic alteration in human malignancy. Unlike normal p53 protein which is unstable and usually cannot be detected by immunohistology, mutated p53 shows a decreased cell turnover rate and overexpression as compared with the wild-type protein. In this study a panel of four anti-p53 antibodies (PAb240, PAb421, PAb1801 and DO7) was applied to 52 cases of Hodgkin's disease: three cases of nodular lymphocytic predominance (LP), 33 cases of nodular sclerosis (NS), and 16 cases of mixed cellularity (MC). The results show that 53 protein is present in the Hodgkin's- and Reed-Sternberg cells in 82% of NS and 94% of MC, but not in nodular LP. It is suggested that mutations of the p53 gene and loss of normal p53 function are frequent in Hodgkin's disease and may be implicated in the pathogenesis of this disease.

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.