Immunohistochemical, molecular, and cytogenetic analysis of a consecutive series of 20 peripheral T-cell lymphomas and lymphomas of uncertain lineage, including 12 Ki-1 positive lymphomas

A novel t(6;7)(p24;q21) in a chronic myelocytic leukemia in complete cytogenetic remission after therapy with imatinib mesylate

Emergence of additional cytogenetic clones in chronic myelocytic leukemia (CML) patients who become Philadelphia chromosome-negative (Ph-) after alpha-interferon therapy (or more recently with imatinib mesylate) have been described. We report here a case of a novel t(6;7)(p21;q23) that developed in a CML patient in complete cytogenetic remission during imatinib therapy. In this case, fluorescence in situ hybridization and reverse transcriptase polymerase chain reaction showed a normal pattern for BCR and ABL genes, suggesting that a different and unrelated clone developed after the disappearance of the Ph chromosome.

Morphological and phenotypic features in pediatric large cell lymphoma and their correlation with ALK expression and the t(2;5)(p23;q35) translocation

Anaplastic large cell lymphoma (ALCL) was proposed as a clinicopathologic entity over 14 years ago, but has been somewhat controversial due to the variability of its defining features and variable occurrence in different age-groups. To evaluate this entity in a pediatric population, 36 cases of childhood large cell lymphoma were evaluated for abnormalities of the anaplastic lymphoma kinase (ALK) gene that has been associated with ALCL morphology and immunophenotype. ALK abnormalities were evaluated by assay for the t(2;5)(p23;q35) translocation by RT-PCR and/or expression of NPM-ALK fusion protein by immunohistochemistry. Results showed 17 patients to have evidence of ALK gene expression. All of these children (mean age, 9.3 years) had tumors that were of T-cell phenotype (with the exception of a single case of null phenotype) and that expressed CD30. In contrast, 19 children with no evidence of ALK expression were older (mean, 12.7 years), and the majority (12/19) had tumors of B-cell phenotype. CD30 was also diffusely expressed in 8 of these 19 tumors. The difference in mean age between the two groups was statistically significant (P = 0.015). In three cases tested for both ALK and the t(2;5), ALK protein was detected in the absence of the t(2;5) translocation but no cases showed the reverse pattern, consistent with ALK fusion to genes other than NPM or activation of the ALK gene by another mechanism. These findings provide further support that ALK-positive ALCL is a distinct pathologic entity among pediatric large cell lymphomas primarily characterized by expression of T-cell markers, CD30, and EMA, and by a younger mean age.

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.

ATIC-ALK: A novel variant ALK gene fusion in anaplastic large cell lymphoma resulting from the recurrent cryptic chromosomal inversion, inv(2)(p23q35)

The subset of CD30-positive anaplastic large cell lymphomas (ALCL) with the NPM-ALK gene fusion arising from the t(2;5)(p23;q35) forms a distinct clinical and prognostic entity. Recently, various cytogenetic, molecular, and protein studies have provided evidence for the existence of several types of variant ALK fusions in up to 20% of ALK+ ALCL, of which only one, a TPM3-ALK fusion resulting from a t(1;2)(q25;p23), has so far been cloned. A cryptic inv(2)(p23q35) has been described as another recurrent cytogenetic alteration involving ALK and an unidentified fusion partner in some ALCL. In a screen for variant ALK gene fusions, we identified two ALCL that were negative for NPM-ALK by reverse transcriptase-polymerase chain reaction, but were positive for cytoplasmic ALK with both polyclonal and monoclonal antibodies to the ALK tyrosine kinase domain, consistent with ALK deregulation by an alteration other than the t(2;5) Case 1 was a T-lineage nodal and cutaneous ALCL in a 52-year-old woman, and Case 2 was a T-lineage nodal ALCL in a 12-year-old girl. FISH analysis confirmed ALK rearrangement in both cases. An inverse polymerase chain reaction approach was then used to identify the ALK translocation partner in Case 1. We found an in-frame fusion of ALK to ATIC, a gene previously mapped to 2q34-q35. We then confirmed by DNA polymerase chain reaction the localization of ATIC to yeast artificial chromosome (YAC) 914E7 previously reported to span the 2q35 break in the inv(2)(p23q35). FISH analysis in Case 1 confirmed rearrangement of YAC 914E7 and fusion to ALK. The ATIC-ALK fusion was confirmed in Case 1 and also identified in Case 2 by conventional reverse transcriptase-polymerase chain reaction using ATIC forward and ALK reverse primers. ATIC encodes an enzyme involved in purine biosynthesis which, like other fusion partners of ALK, is constitutively expressed and appears to contain a dimerization domain. ATIC-ALK fusion resulting from the inv(2)(p23q35) thus provides a third mechanism of ALK activation in ALK+ ALCL.

Long survivors with Ki-1 lymphoma having t(2;5) (p23;q35). Does the presence or absence of t(2;5) influence the prognosis of patients with Ki-1 lymphoma?

We experienced three patients with CD30+ diffuse large cell lymphoma having chromosomal abnormalities. The first patient was an 8-year-old girl with bilateral cervical lymphadenopathy. A biopsy of a cervical lymph node revealed diffuse large cell lymphoma (stage III), positive for CD30 and a chromosomal abnormality, t(2;5). She attained a remission and is now in complete remission 108 months after diagnosis, despite frequent relapses. The second patient was a 13-year-old boy with right axillar and supraclavicular lymph-node adenopathy. A biopsy of a cervical lymph node revealed diffuse large cell lymphoma (stage III), positive for CD30 and a chromosomal abnormality, t(2;5). He attained remission and was in continuous first remission 112 months after diagnosis. The third patient was an 11-year-old boy with fever and bilateral cervical lymph node revealed diffuse large cell lymphoma (stage III), positive for CD30 and chromosomal abnormality without t(2;5). He showed a very aggressive clinical course. Only the patients with Ki-1 lymphoma having t(2;5) survived over 100 months from the diagnosis, despite the advanced stage of the disease. These findings and a review of the literature showed that the presence or absence of t(2;5) may influence the outcome of Ki-1 lymphoma.

Cytogenetic changes in the progression of lymphoma

The study of chromosomal changes related to tumor progression in NHL is complicated by the various histologic classification systems and the lack of large serial studies comparing abnormalities at different disease stages. The T-cell lymphomas frequently involve rearrangements of the T-cell receptors and tumor progression is marked by a change from single cell aberrations and polyclonality in low grade disease to monoclonal formation, complex clones, polyploidy, and abnormalities of 1p, 6q, 7, and 13 in high grade T-NHL. In B-cell NHL, specific translocations and oncogene rearrangements are associated with specific NHL subtypes de novo; many of these translocations involve immunoglobulin genes, such as t(14;18) in follicular lymphoma, t(11;14) in MCL, t(3;14) in DLLC, and t(8;14) in Burkitt's lymphoma. Tumor progression is associated with secondary abnormalities which are generally not confined to a particular NHL subtype. Some abnormalities, such as those involving chromosomes 1, 6, and 17, >4-6 clonal markers/cell, and rearrangements of c-MYC and TP53, have prognostic significance while others, such as trisomies 7, 12, 18, and X, are associated with tumor progression but their influence on overall survival is uncertain.

Chromosomal abnormalities in nodal and extranodal CD30+ anaplastic large cell lymphomas: infrequent detection of the t(2;5) in extranodal lymphomas

To determine the significance of the t(2;5)(p23;q35) translocation in nodal and extranodal anaplastic large cell lymphoma (ALCL), we performed cytogenetic, molecular genetic, and immunohistochemical analyses of tumor tissues from 11 patients with CD30+ ALCL. Three of five patients with nodal ALCL had additional infiltration of the skin. Six patients had extranodal ALCL, two had primary intestinal ALCL, three had a primary cutaneous ALCL, and one had osseous ALCL. Cytogenetic investigation detected the t(2;5) in all patients with nodal ALCL but not extranodal ALCL. Tumor cells in t(2;5)+ lesions also stained immunohistochemically for p80NPM/ALK, whereas no staining for p80NPM/ALK was detected in extranodal ALCL. Two extranodal lesions had NPM/ALK fusion transcripts detected by nested reverse transcriptase-polymerase chain reaction. Fluorescence in situ hybridization analysis of these two lymphomas showed in one case a significant number (4%) of cells with a split hybridization signal, indicative of disruption of the NPM gene. Additional recurrent breakpoints observed in extranodal ALCL were 1p36, 6p25, and 8q24. Loss of genetic material occurred at 6q in one extranodal ALCL. Our results suggest that the t(2;5) more frequently plays a pathogenetic role in primary nodal than in extranodal ALCL and that this translocation may not be the primary event in some CD30+ ALCL.

Malignant histiocytosis. Histologic, cytochemical, chromosomal, and molecular data with a nosologic discussion

Although myelomonoblastic leukemia is thought to originate from a malignant transformation of the stem cell of the mononuclear phagocyte system, malignant histiocytosis (MH) is classically assumed to represent a malignant change of the terminal and fixed elements of this system. Indeed, MH is characterized by the proliferation of large, clear, pleomorphic, "histiocytic-like" HLADR and CD30+ cells resulting in a nodal and extranodal disseminated neoplasm affecting preferentially and severely children and young adults. Although there is broad agreement on the clinicopathologic presentation of this condition, there is currently quite a controversy over the T-lymphoid or histiocytic origin of the proliferative cells that results in a nosologic discussion between the anaplastic large cell lymphoma (ALCL) advocates and the MH supporters. This article has dealt mainly with this nosologic discussion and with the contributions provided by the investigations performed on MH permanent cell lines. These in vitro studies have demonstrated that the proliferation is characterized by a unique chromosomal abnormality, the 5q35bp usually associated with a t(2;5) translocation generating a fusion gene NPM/ALK and the subsequent translation of p80 protein. Although it is known that no single chromosomal abnormality is strictly restricted to a cell lineage, this 5q35bp and associated translocations seem today to represent the hallmark for this condition. In view of these chromosomal aberrations, the CD30+ ALCLs represent a heterogeneous group because 15% to 50% express the NPM/ALK fusion gene. In addition, these in vitro investigations have shown that 5q35bp proliferative cells are glass-adherent, can develop an immunodependent phagocytosis, and are able to reduce NBT and produce TNF-alpha. More significantly, they express constitutively the c-fms (the receptor of the macrophage growth factor) and, under TPA stimulation, are able to modulate the expression of this receptor and its ligand, as well as TNF-alpha and IL-1. None of these cell lines express CD3, but several express CD68 and CD71. In contrast, genomic investigations have shown the underlying existence of monoallelic and even biallelic gene rearrangements for TCR beta and IgJH. In view of these discrepancies between the genomic and phenotypic features of these cells, the histogenetic debate should remain open but must take into account these new chromosomal and molecular data.

Anaplastic large cell lymphoma: a distinct molecular pathologic entity: a reappraisal with special reference to p80(NPM/ALK) expression

The p80(NPM/ALK) expression activated by the t(2;5) (p23;q35) translocation recently has been shown to play an important role in the pathogenesis of anaplastic large cell lymphoma (ALCL). However, the clinicopathologic significance of identification of p80 among ALCL cases has not been completely resolved. Difficulties also exist in the histologic and immunophenotypic identification of ALCL and Hodgkin's disease (HD) as separate processes, often complicating the clinicopathologic evaluation of and therapeutic approach to these entities. In order to clarify these issues, 67 specimens of ALCL and 63 specimens of HD (31 of the nodular-sclerosing type [NS-HD] and 32 of the mixed-cellularity type [MC-HD]) were immunostained using anti-p80 antibody and other relevant markers on paraffin sections. The clinicopathologic and immunophenotypic features were reviewed on the basis of p80 reactivity. The expression of p80 was detected in 43 of 67 cases of ALCL (64%), but none of HD. The p80+ ALCL cases constituted a very homogeneous group of tumors, characterized by the occurrence in a much younger group and relatively more favorable clinical course than the p80- ALCL, which were in keeping with the data previously reported. They showed virtually the identical immunophenotypic findings of p80+, CD30+, EMA+, CD15-, bcl-2-, and Epstein-Barr virus (EBV) with T- and null-cell phenotype, and showed the distinct morphologic features, including three cases of lymphohistiocytic/small-cell variant, as follows: the indented nuclei, often termed as reniform, embryolike, and horseshoelike; multiple, irregular, but indistinct nucleoli; and few reactive cells of eosinophils and epithelioid cells. Conversely, the 24 p80- ALCL cases, in which epithelial membrane antigen (EMA) and bcl-2 positivities were 33% and 55%, respectively, were heterogeneous and could be subdivided into five different categories, namely (a) 11 cases of HD-like ALCLs, (b) six cases of p80 common ALCL, (c) three cases of secondary ALCL, (d) two cases of primary cutaneous ALCL, and (e) two cases of primary classical ALCL that lacked p80 expression. This study clearly demonstrated that the immunohistochemical detection of p80 is of a crucial importance in delineating the biologically distinct entity of "primary classical ALCL" from various diseases that show morphologic and immunohistologic overlap, including HD and HD-like ALCL.

Detection of Anaplastic Lymphoma Kinase (ALK) and Nucleolar Protein Nucleophosmin (NPM)-ALK Proteins in Normal and Neoplastic Cells With the Monoclonal Antibody ALK1

The t(2; 5)(p23;q35) translocation, associated with anaplastic large-cell lymphoma (ALCL), results in the production of the nucleolar protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) protein. This report describes an immunocytochemical study of the distribution of ALK and NPM-ALK proteins using a new monoclonal antibody, ALK1, that recognizes a formalin resistant epitope in both the 80-kD NPM-ALK chimeric and the 200-kD normal human ALK proteins. Cytoplasmic and nuclear labeling was seen in the t(2; 5)+ SU-DHL-1 and Karpas 299 cell lines. Normal ALK protein expression was restricted to the central nervous system (in scattered neurons, glial cells, and endothelial cells). Two hundred and thirty-nine cases of lymphoma and 80 nonhematopoietic tumors were immunostained. Antibody ALK1 labeled 53.4% (39 of 73 cases) of CD30+ ALCL. A case of ALCL with a t(1; 2) translocation was ALK1+. Three cases of CD30− ALCL with prominent nucleoli showed a unique pattern of coarse granular cytoplasmic labeling. All other tumors, including Hodgkin's disease and lymphomatoid papulosis, were ALK1−. These results indicate that reliable immunostaining of routine biopsy material for NPM-ALK and ALK proteins is feasible. Such analysis is of diagnostic importance, especially because t(2; 5)+ ALCL cases have a good prognosis with appropriate treatment.

The clinicopathological features of anaplastic large cell lymphomas expressing p80NPM/ALK

The classification of malignant lymphoma has been based on morphological and immunophenotypical findings for a long time. Recently, as chromosomal and genomic abnormalities which closely relate to the specific subtypes of lymphoma are revealed, these factors becoming much more important in the evaluation of differences in clinicopathological features of the various lymphoma subtypes. Anaplastic large cell lymphoma (ALCL) is a subtype of non-Hodgkin's lymphoma (NHL) involving large CD30+ neoplastic cells, which occasionally carries the chromosomal translocation t(2;5)(p23;q35). We have recently found a novel hyperphosphorylated 80-kDa protein tyrosine kinase, p80 which is expressed specifically in human ALCLs with this translocation. Subsequent cDNA cloning showed p80 to be a fusion protein of two genes, the novel tyrosine kinase gene and the nucleophosmin gene, in accordance with the sequence of the NPM/ALK gene. In order to clarify the clinicopathologic features of p80-carrying ALCLs, we developed an anti-p80 polyclonal antibody, which immunoprecipitated, immunoblotted and immunostained p80 specifically. When paraffin sections of 105 cases of ALCL were stained using the anti-p80 antibody, 30 were shown to be p80 positive Clinicopathological comparison between p80-positive and p80-negative ALCLs revealed that the p80-positive cases occurred in a much younger patient age group and that the patients showed a far better 5-year survival rate. These data suggest that p80-positive ALCL is a distinct entity and should be differentiated from p80-negative ALCL.

Detection of the NPM-ALK genomic rearrangement of Ki-1 lymphoma and isolation of the involved NPM and ALK introns

The breakpoints of the translocation t(2;5)(p23;q35) associated with Ki-1-positive anaplastic large-cell lymphoma (Ki-1 ALCL) involve a novel tyrosine kinase gene, ALK, at 2p23 and the nucleophosmin gene, NPM, at 5q35. Reverse transcriptase-polymerase chain reaction (RT-PCR) using NPM and ALK primers detects a consistent fusion product in Ki-1 ALCL cases with the translocation, resulting from genomic breakpoints within the same respective introns of NPM and ALK. To examine the feasibility of long-range DNA PCR with the same exonic NPM and ALK primers for the detection of the genomic NPM-ALK rearrangement, we examined 20 cases of Ki-1 ALCL previously characterized by NPM-ALK RT-PCR. Ten cases were positive for the NPM-ALK fusion RNA and 10 were negative. We first confirmed that both the NPM and ALK normal introns are relatively short, approximately 1 and 2 kb, respectively, suggesting that the largest possible size for the chimeric NPM-ALK intron would be about 3 kb. All 10 cases positive by RT-PCR were also positive by long-range DNA PCR. The DNA PCR products ranged, as expected, from the sizes of the normal introns, between 0.5 and 2.5 kb. All 10 RT-PCR-negative cases were also negative by long-range DNA PCR, and control templates for RT-PCR and long-range DNA PCR were successfully amplified. Thus, we have shown that the introns involved by the NPM-ALK rearrangement seen in some Ki-1 lymphomas are relatively short, making the genomic rearrangement amenable to reliable detection by long-range DNA PCR. Furthermore, the variability observed in the sizes of chimeric introns in evidence against clustering of the genomic breakpoints within these introns.

Detection of the t(2;5)(p23;q35) chromosomal translocation in large B-cell lymphomas other than anaplastic large cell lymphoma

In general, the large cell lymphomas are a cytogenetically heterogeneous group of diseases, and the cytogenetic findings do not correlate with morphological findings in this group of malignant lymphomas. The CD30-positive anaplastic large cell lymphomas, however, are thought to be an exception, with the t(2;5) reported to correlate with the morphological changes of this disease entity. A subgroup of Hodgkin's disease cases have been reported by some investigators to have the t(2;5) translocation, leading to speculation that these two diseases are related. In the current study, the authors used a sensitive reverse transcriptase polymerase chain reaction (RT-PCR) methodology to evaluate the frequency of t(2;5) in 33 cases of large cell lymphoma, of B lineage, other than anaplastic large cell lymphoma. The authors detected evidence of t(2;5) in four of the cases (12%), a frequency similar to that of the authors' previous study of cases of CD30 positive anaplastic large cell lymphoma. Three of the positive large B-cell lymphoma cases were CD30 negative and were morphologically indistinguishable from the cases without evidence of t(2;5). The fourth case had a subpopulation of CD30 positive cells but also did not have morphological features of anaplastic large cell lymphoma. These results would suggest that t(2;5) is not restricted to cases of malignant lymphomas with anaplastic morphology or to CD30 expression.

Molecular variant of the NPM-ALK rearrangement of Ki-1 lymphoma involving a cryptic ALK splice site

The breakpoints of the translocation t(2;5)(p23;q35) associated with Ki-1-positive anaplastic large cell lymphoma (Ki-1 ALCL) have recently been cloned. They involve a novel tyrosine kinase gene, ALK, at 2p23 and the nucleophosmin gene, NPM, at 5q35. Reverse transcriptase-polymerase chain reaction (RT-PCR) with NPM and ALK primers detects a consistent fusion product in Ki-1 ALCL cases that have the translocation. In the course of a survey of 15 cases of Ki-1 ALCL, we identified a single case with a slightly smaller NPM-ALK RT-PCR product, among 12 cases positive for this fusion RNA. Sequencing of this novel NPM-ALK RT-PCR product showed an in-frame junction of NPM to ALK, 30 bases distal to the usual ALK junction site, but at the usual NPM Junction site. The predicted chimeric protein in this case is thus shorter by 10 amino acids, but the putative ALK catalytic domain remains intact. PCR with ALK primers bracketing the novel fusion point, performed on either cDNA or genomic DNA, yielded the same product, confirming that this novel ALK fusion point was located within an exon. Hybridization analysis of the genomic junction fragment isolated by long-range DNA PCR suggested that the ALK genomic breakpoint was also exonic. Cloning and sequencing of the genomic breakpoint confirmed that the break occurred within the 5' portion of the ALK exon participating in the fusion junction, 28 bases 3' to the normal ALK exon boundary, resulting in the use of a cryptic splice acceptor site two bases distal to the breakpoint. This case demonstrates that, in translocations resulting in chimeric transcripts, genomic breakpoints may rarely lie within an exon, provided that the reading frame is maintained and no domains presumed critical to tumorigenesis are deleted.

Cytology of extranodal Ki-1 anaplastic large cell lymphoma

Ki-1-positive anaplastic large-cell lymphoma (ALCL) is an uncommon neoplasm which may present with extranodal as well as nodal disease. By definition, the tumor cells are immunoreactive for Ki-1 or Ber-H2 antigen (CD30). There have been few published cytologic descriptions of this lymphoma, or of its detection in extranodal sites. We describe the cytologic findings in five cases of extranodal Ki-1 lymphoma. Cytologic findings in all five cases were similar and consisted of a heterogeneous population of lymphocytes and bizarre, pleomorphic tumor cells. These cells were characterized by generous amounts of vacuolated, basophilic cytoplasm, eccentric, multilobulated nuclei with some showing "wreath-like" configurations. Some nuclei contained huge nucleoli simulating Reed-Sternberg cells. All cases showed the characteristic surface membrane and cytoplasmic paranuclear dot-like staining for CD30. Our findings indicate that fine-needle aspiration and exfoliative cytology have a useful role in the diagnosis of Ki-1 ALCL in extranodal sites. Furthermore, effusions containing anaplastic cells suspicious for lymphoma, particularly in AIDS patients, should be immunostained with antibodies to CD30.

Molecular analysis of the NPM-ALK rearrangement in Hodgkin's disease

The fusion gene NPM-ALK occurs in a subset of anaplastic large cell lymphomas (ALCLs), as a result of a chromosomal translocation, t(2;5) (p23;q35). It has been suggested that Hodgkin's disease (HD) and ALCL share a common histogenesis because of pathological and phenotypical similarities. In order to check this hypothesis, reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to detect the hybrid NPM-ALK gene in 30 tumour samples, including 22 lymph node biopsies from HD and eight ALCL specimens. The threshold level of sensitivity was shown to reach at least 1/10(4) by dilution experiments using cell lines as positive and negative controls. The expected 177 bp product indicative of the NPM-ALK rearrangement was identified in Karpas 299 and SUDHL-1 cell lines and in two out of eight ALCLs. The 22 HD cases were negative, even after two successive tests. Thus, since the ALCL-specific genetic alteration was absent in our series of HD cases, the present study does not support the hypothesis that HD and ALCL are histogenetically related entities.

Unclassifiable high grade malignant T-cell lymphoma with clonal evolution

We report a case of leukemic malignant T-cell lymphoma with mixed small and large cells. The small cells displayed a mature CD8-positive phenotype, a diploid DNA distribution by cell cycle analysis, and structural karyotypic abnormalities. Large cells were near triploid, showed additional structural cytogenetic abnormalities and a more immature membrane phenotype without CD8 expression. Altogether, these data provide suggestive evidence for a clonal evolution from a mature small cell T-cell lymphoma to a more immature large cell proliferation.

Primary Ki-1-positive anaplastic large-cell lymphoma: a distinct clinicopathologic entity

The morphology of anaplastic large-cell lymphoma (ALCL) is associated with a clinical syndrome of peripheral lymphadenopathy (> 80%) and frequent extranodal disease (> 40%) in children and young adults (median age < 40 yrs.). Skin lesions occur in more than 20% of patients; other extranodal sites are bone, soft tissue, gastro-intestinal tract, lung, and pleura. Marrow involvement is infrequent (< 10%). Features that distinguish ALCL from Hodgkin's disease (HD) are noncontiguous nodal disease (> 50%), infrequent mediastinal mass (< 20%), and frequent inguinal lymphadenopathy (> 40%). Most patients present with stage III/IV disease. Stage is highly predictive of achieving complete remission, disease-free survival, and overall survival. Localized skin lesions have an excellent prognosis and occasional spontaneous regressions are noted. Distinctive histopathologic features of ALCL are partial lymph node involvement with sinus infiltration, sparing of B-cell regions, and tumor cell pleomorphism. Other features are high mitotic rate, necrosis, fibrosis, and plasma cell infiltrates. Morphologic variants of ALCL resemble carcinoma, syncytial variant of nodular sclerosing HD, true histiocytic lymphoma or interdigitating cell sarcoma, and mycosis fungoides. ALCL can be distinguished from these morphologically similar disorders by immunophenotype (CD30+, CD45+, CD15-, EMA+, BNH9+, keratin-, lysozyme-). A recurrent cytogenetic translocation, t(2;5) (p23; q35), has been observed among morphologic variants, including a small-cell-predominant variant and tumor cell line which contains a spectrum of small cerebriform and large anaplastic CD30+ cells. 70% of ALCL cases are of T-cell lineage, 15% B, 5% T/B, and 10% undefined.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaplastic large cell lymphoma of true histiocytic origin in an infant: unusual clinical, hematological, and cytogenetic features

We report here the case of a 7-month-old boy who developed anaplastic large cell lymphoma of true histiocytic origin or malignant histiocytosis, with fever, bone and bone marrow infiltration. Usual clinical features were absent. The neoplastic nature of the disease was supported by the presence of clonal chromosomal abnormalities [t(6;8)(p23;p21),der(8)del(8)(q11aq13), der(22) t(11;22) (q13;13)]. Neither B nor T lineage could be demonstrated here. Morphology, ultrastructural analysis, surface antigens expression, and cytogenetics were more specific for the monocyte-macrophage lineage.

T-cell receptor gene rearrangement studies as a diagnostic tool in lymphoproliferative skin diseases

The growth of our knowledge in T-cell biology, in particular the molecular biology of the T-cell receptor (TCR), has provided a means to molecularly characterize lymphoproliferative diseases of the skin based on the presence or absence of a clonal population of T lymphocytes. TCR gene rearrangement studies, by Southern blot analysis, have aided the investigative dermatologist in gaining insights into the pathogenesis and clonal evolution of lymphoproliferative skin diseases. In addition, the application of TCR gene rearrangement studies as a diagnostic aid in the evaluation of lymphoproliferative skin diseases has been introduced into clinical dermatology. Despite its enormous research value, TCR gene rearrangement studies presently have limited applications as an independent diagnostic tool. However, as our knowledge and experience grows and as the application of new techniques provides us with greater detection sensitivity and specificity, the diagnostic utility of TCR gene rearrangement studies will be enhanced.

Chromosome analysis in the management of patients with non-Hodgkin's lymphoma

Analysis of chromosome abnormalities in non-Hodgkin's lymphoma has stimulated a basic inquiry into the mechanisms of gene deregulation in human tumors. A growing literature has also correlated cytogenetic and molecular genetic features of lymphoma with patient prognosis and other clinical features of the disease. The goal of this report is to review those genetic abnormalities which are currently useful in the clinical management of patients with lymphoma, and to provide a conceptual framework for this growing literature.

Distinct patterns of chromosome abnormalities characterize childhood non-Hodgkin's lymphoma

We report here cytogenetic studies of a series of 23 childhood non-Hodgkin's lymphomas (NHL), a group that has previously not been subjected to detailed cytogenetic analysis. Combining our results with data from 25 tumours in the published literature, we have performed the first cytogenetic analysis of a large series of childhood NHL. Our results show that the cytogenetic changes encountered in NHL of children are distinct and may be different from those seen in NHL of adults reflecting the previously recognized differences in histological presentation and clinical behaviour of the two entities. Thus, the most frequently occurring translocation in B-cell lesions in children was t(8;14)(q24;1q32). Other translocations frequently seen in adults such as t(14;18)(q32;q21),t(11;14)(q13;q32) and t(3;22)(q27;q11) were either rare or so far not seen in children, although reciprocal translocations appeared to be generally prevalent in childhood NHL. Combining our data with those in the published literature, we have identified two new recurring translocations [t(1;17)(p36;q21) and t(1;14)(p36;q22)], and a recurring duplication [dup(11)(q13;q23)] in this group of lymphomas. In addition, our literature survey identified a third recurring translocation [t(5;14)(q23;q32)] which was previously reported in two cases of childhood NHL. Our analysis also showed differences in the types of nonrandom translocations between childhood NHL and acute lymphoblastic leukaemia (ALL) in children suggesting that biologically these entities are different from one another. This study thus uncovers patterns of chromosome change associated with childhood lymphoma thus providing new opportunities for investigation of their clinical significance by correlation analysis and biological significance by molecular analysis.

Clonal cytogenetic abnormalities in Hodgkin's disease

Cytogenetic studies of Hodgkin's disease (HD), in contrast to those of non-Hodgkin's lymphoma (NHL), have been limited to small numbers of cases with infrequently recurring aberrations, underscoring the need for additional studies in establishing a coherent cytogenetic picture of HD. Over a 6 1/2-year period, we received 95 specimens of HD for cytogenetic analysis. Analyzable chromosome preparations were obtained in 70 cases, of which 57 (81%) showed only normal metaphases. In the remaining 13 cases (19%), karyotypic abnormalities were observed that were nonclonal in 3 and clonal in 10. The latter 10 cases included 6 of the nodular sclerosis subtype, 3 mixed cellularity, and 1 lymphocyte-depleted; 8 of the specimens were obtained pretreatment and 2 posttreatment. Two of the cases had a clonal numerical aberration, monosomy 17 in one and trisomy 13 in the other, as their sole abnormality. The remaining 8 cases showed complex karyotypes with multiple structural rearrangements; in 3 of these, the abnormal clone was near-tetraploid. Bands involved more than once included 1p36, 1q21, and 4q35, each in 2 cases. Arms involved more than once included 6q (6q13,6q23), 9p (9p13,9p21), and 5q (5q15,5q35). Three patients had loss of part or all of 6q (del(6)(q13),del(6)(q23),i(6p). Bands 14q32 and 18q21 were not involved in any case, contrary to some previous reports. Our results confirm the frequent occurrence of 1p, 1q, and 6q abnormalities in HD. In addition, we have identified a 5q35 breakpoint, which has recently been shown to be highly specific for Ki-1-positive NHL in a case of typical nodular sclerosis HD. Its presence in HD may represent a cytogenetic link between the two entities, which are immunophenotypically related but clinically and histologically distinct.

Cytogenetic analysis of 434 consecutively ascertained specimens of non-Hodgkin's lymphoma: correlations between recurrent aberrations, histology, and exposure to cytotoxic treatment

Cytogenetic abnormalities in non-Hodgkin's Lymphoma (NHL) provide a model system for the analysis of the role of multiple genomic aberrations in human malignancy. In order to define correlations with histology, tumor evolution, and the effects of genotoxic exposure, cytogenetic analysis was performed on 434 specimens of NHL derived from 423 patients consecutively ascertained over a 5-year period (1984-1989). Six recurring translocations (RT) were observed: t(14;18)(q32;q21), t(8;14)(q24;q32), t(11;14)(q13;q32), t(3;22)(q27;11), t(2;5)(p23;q35), and t(1;6)(q21;q25). No translocation was specific to a single histologic subtype. Other structural chromosome abnormalities were analyzed according to break site; groups of related breaks were considered together for statistical analysis. Recurring other structural and numerical aberrations (ROA) encountered in greater than 10% of specimens included rearrangements with breaks at bands 1p32-36, 1q21-23, 6q21-25, and trisomies of chromosomes 7 and 12. ROA with one of these breaks or numerical abnormalities were the sole abnormalities in at least two cases. Correlations were observed among ROA and between ROA and histologic subtypes. Trisomy 7, breaks at 1q21-23, 1p32-36, 6q21-25, and 7q32 were associated with t(14;18); trisomy 18 was associated with trisomy 3; and structural abnormalities of chromosome 17 were associated with breaks at 1p32-36 and 6q21-25. Trisomy 7 and trisomy 12 were more frequent in t(14;18)-bearing intermediate to high grade tumors compared to low grade tumors. Trisomy 12 and breaks at band 1p22 were associated with large cell diffuse lymphomas. Incidence rates of reciprocal translocations, ROA, and measures of karyotypic complexity, including number of breakpoints and marker chromosomes were compared in pretreatment and posttreatment samples. Karyotypic complexity was greater in the posttreatment samples, reflecting an increased frequency of nonrecurring and low incidence aberrations. These results better define the association of genomic aberrations and tumorigenesis, histologic transformation, and tumor progression.

Structural alterations in the 5' region of the BCL2 gene in follicular lymphomas with BCL2-MBR or BCL2-MCR rearrangements

We report a new class of molecular lesions in the 5' region of the BCL2 protooncogene when it undergoes a t(14;18) translocation-associated rearrangement in the major break cluster (MBR) or minor break cluster (MCR) regions. Among 52 tumors assayed for BCL2 rearrangements using the MBR, MCR, and 5' probes, seven (six with MBR and one with MCR translocation breaks) showed aberrant bands in unique enzyme digests of DNA hybridized with the 5' probe. The aberrant bands in four tumors were in HindIII digests, in two they were in EcoRI digests, while the aberrant band in one was in a BamHI digest. The two EcoRI bands and two of the four HindIII bands were of identical sizes. Germline polymorphisms as the source of these bands was ruled out by appropriate control experiments. These results suggest that the bands were derived from point mutations or small deletions in the 5' region of BCL2. The significance of this alteration to BCL2 function in translocation-carrying tumors remains to be determined.