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The International Peripheral T-Cell Lymphoma Project is a collaborative effort designed to gain better understanding of peripheral T-cell and natural killer (NK)/T-cell lymphomas (PTCLs). A total of 22 institutions in North America, Europe, and Asia submitted clinical and pathologic information on PTCLs diagnosed and treated at their respective centers. Of the 1314 eligible patients, 181 had anaplastic large-cell lymphoma (ALCL; 13.8%) on consensus review: One hundred fifty-nine had systemic ALCL (12.1%) and 22 had primary cutaneous ALCL (1.7%). Patients with anaplastic lymphoma kinase–positive (ALK+) ALCL had a superior outcome compared with those with ALK−ALCL (5-year failure-free survival [FFS], 60% vs 36%; P= .015; 5-year overall survival [OS], 70% vs 49%; P= .016). However, contrary to prior reports, the 5-year FFS (36% vs 20%; P= .012) and OS (49% vs 32%; P= .032) were superior for ALK−ALCL compared with PTCL, not otherwise specified (PTCL-NOS). Patients with primary cutaneous ALCL had a very favorable 5-year OS (90%), but with a propensity to relapse (5-year FFS, 55%). In summary, ALK−ALCL should continue to be separated from both ALK+ALCL and PTCL-NOS. Although the prognosis of ALK−ALCL appears to be better than that for PTCL-NOS, it is still unsatisfactory and better therapies are needed. Primary cutaneous ALCL is associated with an indolent course.

The International Peripheral T-Cell Lymphoma Project is a collaborative effort designed to gain better understanding of peripheral T-cell and natural killer (NK)/T-cell lymphomas (PTCLs). A total of 22 institutions in North America, Europe, and Asia submitted clinical and pathologic information on PTCLs diagnosed and treated at their respective centers. Of the 1314 eligible patients, 181 had anaplastic large-cell lymphoma (ALCL; 13.8%) on consensus review: One hundred fifty-nine had systemic ALCL (12.1%) and 22 had primary cutaneous ALCL (1.7%). Patients with anaplastic lymphoma kinase–positive (ALK+) ALCL had a superior outcome compared with those with ALK− ALCL (5-year failure-free survival [FFS], 60% vs 36%; P = .015; 5-year overall survival [OS], 70% vs 49%; P = .016). However, contrary to prior reports, the 5-year FFS (36% vs 20%; P = .012) and OS (49% vs 32%; P = .032) were superior for ALK− ALCL compared with PTCL, not otherwise specified (PTCL-NOS). Patients with primary cutaneous ALCL had a very favorable 5-year OS (90%), but with a propensity to relapse (5-year FFS, 55%). In summary, ALK− ALCL should continue to be separated from both ALK+ ALCL and PTCL-NOS. Although the prognosis of ALK− ALCL appears to be better than that for PTCL-NOS, it is still unsatisfactory and better therapies are needed. Primary cutaneous ALCL is associated with an indolent course.

Primary cutaneous lymphomas are currently classified by the European Organization for Research and Treatment of Cancer (EORTC) classification or the World Health Organization (WHO) classification, but both systems have shortcomings. In particular, differences in the classification of cutaneous T-cell lymphomas other than mycosis fungoides, Sézary syndrome, and the group of primary cutaneous CD30+ lymphoproliferative disorders and the classification and terminology of different types of cutaneous B-cell lymphomas have resulted in considerable debate and confusion. During recent consensus meetings representatives of both systems reached agreement on a new classification, which is now called the WHO-EORTC classification. In this paper we describe the characteristic features of the different primary cutaneous lymphomas and other hematologic neoplasms frequently presenting in the skin, and discuss differences with the previous classification schemes. In addition, the relative frequency and survival data of 1905 patients with primary cutaneous lymphomas derived from Dutch and Austrian registries for primary cutaneous lymphomas are presented to illustrate the clinical significance of this new classification.

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with recognized variability in clinical outcome, genetic features, and cells of origin. To date, transcriptional profiling has been used to highlight similarities between DLBCL tumor cells and normal B-cell subtypes and associate genes and pathways with unfavorable outcome. To identify robust and highly reproducible DL-BCL subtypes with comprehensive transcriptional signatures, we used a large series of newly diagnosed DLBCLs, whole genome arrays, and multiple clustering methods. Tumors were also analyzed for known common genetic abnormalities in DLBCL. There were 3 discrete subsets of DLBCL—“oxidative phosphorylation,” “B-cell receptor/proliferation,” and “host response” (HR)—identified characterized using gene set enrichment analysis and confirmed in an independent series. HR tumors had increased expression of T/natural killer cell receptor and activation pathway components, complement cascade members, macrophage/dendritic cell markers, and inflammatory mediators. HR DLB-CLs also contained significantly higher numbers of morphologically distinct CD2+/CD3+tumor-infiltrating lymphocytes and interdigitating S100+/gamma interferon-induced lysosomal transferase–positive (GILT+) CD1a–/CD123–dendritic cells. The HR cluster shared features of histologically defined T-cell/histiocyte-rich B-cell lymphoma, including fewer genetic abnormalities, younger age at presentation, and frequent splenic and bone marrow involvement. These studies identify tumor microenvironment and host inflammatory response as defining features in DLBCL and suggest rational treatment targets in specific DLBCL subsets.

Mediastinal large B-cell lymphoma (MLBCL) is a recently identified subtype of diffuse large B-cell lymphoma (DLBCL) that characteristically presents as localized tumors in young female patients. Although MLBCL has distinctive pathologic features, it clinically resembles the nodular sclerosis subtype of classical Hodgkin lymphoma (cHL). To elucidate the molecular features of MLBCL, we compared the gene expression profiles of newly diagnosed MLBCL and DLBCL and developed a classifier of these diseases. MLBCLs had low levels of expression of multiple components of the B-cell receptor signaling cascade, a profile resembling that of Reed-Sternberg cells of cHL. Like cHLs, MLBCLs also had high levels of expression of the interleukin-13 (IL-13) receptor and downstream effectors of IL-13 signaling (Janus kinase-2 [JAK2] and signal transducer and activator of transcription-1 [STAT1]), tumor necrosis factor (TNF) family members, and TNF receptor-associated factor-1 (TRAF1). Increased expression of STAT1 and TRAF1 in MLBCL was confirmed by immunohisto-chemistry. Given the TRAF1 expression and known link to nuclear factor–κB (NF- κB), MLBCLs were also evaluated for nuclear translocation of c-REL protein. In almost all cases, c-REL was localized to the nucleus, consistent with activation of the NF-κB pathway. These studies identify a molecular link between MLBCL and cHL and a shared survival pathway.

Expression of ALK protein by lymphoid cells and the description of variant anaplastic lymphoma kinase (ALK) translocations have typically been restricted to cases of T-cell and null anaplastic large-cell lymphoma (ALCL). All such cases result from a novel fusion created by the ALKgene on chromosome 2p23 and NPMon 5q35 or other variant translocation partners. A rare variant of diffuse large B-cell lymphoma (DLBCL), originally described in 1997, was thought to overexpress full-length ALK in contrast to a chimeric protein characteristic of ALCL. However, full-length ALK protein lacks tyrosine kinase activity and thus the mechanism of oncogenesis has remained elusive. We describe 6 cases of ALK+DLBCL characterized by a simple or complex t(2;17)(p23;q23) involving the clathrin gene (CLTC) at chromosome band 17q23 and the ALKgene at chromosome band 2p23. All cases were studied using fluorescence in situ hybridization (FISH), complemented in one case with standard cytogenetic analysis, multicolor karyotyping (M-FISH), and reverse transcriptase-polymerase chain reaction. These results clearly demonstrate that most cases of ALK+DLBCL share the same mechanism of deregulated ALK expression. Moreover, these results demonstrate the presence of CLTC-ALKfusions in these tumors and extend the list of diseases associated with this genetic abnormality to include classical T-cell or null ALCL, ALK+DLBCL, and inflammatory myofibroblastic tumors. (Blood. 2003;102:2568-2573)

Introduction:Burkitt lymphoma (BL) accounts for approximately 50% of all pediatric non-Hodgkin lymphomas compared to 1-2% in adults. Adult BL (aBL) remains a poorly understood entity and its relationship to pediatric BL (pBL) and to DLBCL has not been fully elucidated. The variable treatment outcomes between these entities necessitate a more thorough understanding of the genetic and molecular features underlying their biology to enable better prognostication and more effective treatments. We sought to comprehensively determine genetic features shared with DLBCL and those that are unique to BL, to further delineate genetic subgroupings within each entity.

The WHO (World Health) Organization Classification recognizes two distinct subtypes of anaplastic large cell lymphoma: Primary systemic and Primary cutaneous types, which have differences in immunophenotype, genetics, and clinical behavior. It is now known that approximately 60% of systemic ALCLs express the anaplastic lymphoma kinase (ALK) protein (ALK-pos) and have a significantly superior survival to ALK-neg cases. Since ALK-neg ALCL appear to have a prognosis similar to peripheral T-cell lymphoma unspecified (PTCL-U), it has been suggested that they should be classified as PTCL-U. Herein, we report the clinical features of newly diagnosed systemic and cutaneous ALCL from the International T-cell Lymphoma Study Group. Materials and Methods: 186 cases of ALCL were identified by the WHO disease definitions: systemic ALCL 163 (88%) (ALK-pos 91 (56%), 72(44%) ALK-neg), and 23 (17%) cutaneous ALCL (cut ALCL). The median age of ALK-pos, ALK-neg and cut ALCL was 32, 57.5 and 54, respectively. There was a male predominance for all subtypes. Most cases of systemic ALCL presented with stage III or IV disease (64% ALK-pos, 58% ALK-neg) and in contrast, 87% of cut ALCL had localized disease. The majority of patients with systemic ALCL were treated with CHOP-type chemotherapy. Most patients with cut ALCL (91%) received additional therapy: 13 (62%) CHOP-type chemotherapy, 11(52%) chemoradiation, 4 (19%) radiation alone. Results: The 5y failure free survival (FFS) and overall survival (OS) was superior for ALK-pos ALCL (70.5% and 58%) compared to ALK-neg ALCL (49% and 36%) (p=.022 and p=.014 for FFS and OS, respectively). Comparison of ALK-pos (n=16) and ALK-neg ALCL (n=23) patients with limited stage disease (defined as stage I or II, no B symptoms and non-bulky) failed to demonstrate a significant difference in FFS (p=.54) or OS (p=.21). Both ALK-pos and ALK-neg ALCL had a superior FFS (ALK-pos p< .001; ALK-neg p=.012) and OS (ALK-pos p<.001; ALK-neg p=.032) than PTCL-U. In contrast to PTCL-U, an apparent plateau was observed on the FFS curve for ALK-neg ALCL. For cut ALCL, the 5y FFS and OS was 90% and 57%, superior to systemic ALCL. The administration of chemotherapy did not appear to impact outcome in patients with cut ALCL (p=.64). Among the prognostic factors analyzed, the international prognostic index (IPI) was the most effective for defining risk categories in ALK-neg ALCL. For ALK-pos ALCL both the IPI and anemia (Hb < 11.0 g/L) were effective in risk-group stratification in multivariate analysis. Conclusions: Similar to prior reports, ALK-pos ALCL has a superior outcome to ALK-neg ALCL. For limited stage patients, this survival difference is not apparent, suggesting that a small subgroup of patients with ALK-neg ALCL may have a more favorable prognosis, similar to ALK-pos ALCL. The IPI is effective in both ALK-neg and ALK-pos ALCL at risk stratification. Finally, contrary to prior reports, ALK-neg ALCL patients appear to have a superior outcome to PTCL-U and an apparent plateau in the FFS curve. These results suggest that ALK-neg ALCL should still be distinguished from both ALK-pos ALCL and PTCL-U.