Laurence Lamant

Recurrent TET2 mutations in peripheral T-cell lymphomas correlate with TFH-like features and adverse clinical parameters.

Inactivating mutations of the Ten-Eleven Translocation 2 (TET2) gene were first identified in myeloid malignancies and more recently in peripheral T-cell lymphomas (PTCLs). In the present study, we investigated the presence of TET2 coding sequence mutations and their clinical relevance in a large cohort of 190 PTCL patients. TET2 mutations were identified in 40 of 86 (47%) cases of angioimmunoblastic T-cell lymphoma (AITL) and in 22 of 58 (38%) cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), but were absent in all other PTCL entities, with the exception of 2 of 10 cases of enteropathy-associated T-cell lymphoma. Among PTCL-NOS, a heterogeneous group of lymphoma-comprising cases likely to derive from Th follicular (T(FH)) cells similarly to AITL, TET2 mutations were more frequent when PTCL-NOS expressed T(FH) markers and/or had features reminiscent of AITL (58% vs 24%, P = .01). In the AITL and PTCL-NOS subgroups, TET2 mutations were associated with advanced-stage disease, thrombocytopenia, high International Prognostic Index scores, and a shorter progression-free survival.

Expression of the ALK Tyrosine Kinase Gene in Neuroblastoma

ALK (anaplastic lymphoma kinase) is a tyrosine kinase receptor, expressed as part of the chimeric NPM-ALK protein, in anaplastic large cell lymphomas (ALCLs) exhibiting the t(2;5)(p23;q35) translocation. As a result of this translocation, the NPM (nucleophosmin) gene is fused to the portion of the ALK gene encoding its intracytoplasmic segment. In normal mouse tissues, mRNA encoding the Alk receptor has been found only in neural cells, suggesting involvement of this receptor in the development of the nervous system. The purpose of the present study was to examine the presence of ALK transcripts and protein in normal human tissues and a variety of cell lines and human tumors. Emphasis was placed on neuroblastomas because other tyrosine kinase receptors are expressed in human neuroblastomas. Fifty-six cell lines, including 29 lines of neural origin, and lymphoid and nonlymphoid tissue specimens, including 24 neuroblastomas, were investigated for ALK expression, using reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry. The results confirmed that mRNA encoding ALK protein was not detectable in any normal or neoplastic hematopoietic tissue tested, except for t(2;5)-positive ALCL. The salient finding was that 13 of the 29 cell lines of neural origin and 22 of 24 neuroblastomas were found to express ALK transcripts and ALK protein. However, no correlation was evident between any known prognostic factors and the level of ALK expression.

Genomic profiling reveals different genetic aberrations in systemic ALK-positive and ALK-negative anaplastic large cell lymphomas.

Anaplastic large cell lymphoma (ALCL) is a T/null‐cell neoplasm characterized by chromosomal translocations involving the anaplastic lymphoma kinase (ALK) gene (ALK). Tumours with similar morphology and phenotype but negative for ALK have been also recognized. The secondary chromosomal imbalances of these lymphomas are not well known. We have examined 74 ALCL, 43 ALK‐positive and 31 ALK‐negative, cases by comparative genomic hybridization (CGH), and locus‐specific alterations for TP53 and ATM were examined by fluorescence in situ hybridization and real‐time quantitative polymerase chain reaction. Chromosomal imbalances were detected in 25 (58%) ALK‐positive and 20 (65%) ALK‐negative ALCL. ALK‐positive ALCL with NPM‐ALK or other ALK variant translocations showed a similar profile of secondary genetic alterations. Gains of 17p and 17q24‐qter and losses of 4q13‐q21, and 11q14 were associated with ALK‐positive cases (P = 0·05), whereas gains of 1q and 6p21 were more frequent in ALK‐negative tumours (P = 0·03). Gains of chromosome 7 and 6q and 13q losses were seen in both types of tumours. ALCL‐negative tumours had a significantly worse prognosis than ALK‐positive. However no specific chromosomal alterations were associated with survival. In conclusion, ALK‐positive and negative ALCL have different secondary genomic aberrations, suggesting they correspond to different genetic entities.

PCR analysis of immunoglobulin heavy chain (IgH) and TcR-gamma chain gene rearrangements in the diagnosis of lymphoproliferative disorders : results of a study of 525 cases

This report summarizes a cumulative 4-year experience in polymerase chain reaction (PCR) analysis of immunoglobin heavy chain (IgH) and TcR-γ chain gene rearrangements in 525 cases of lymphoproliferative disorders. Because the sensitivity of the PCR methodology was found to be tissue dependent, in the study of the presence of clonal cell population in tissues containing a small number of polyclonal lymphocytes, such as skin and gastrointestinal biopsy specimens, we used the multiple–PCR run approach. In this latter methodology, we repeat the PCR reaction from the same sample at least three times to confirm the reproducibility of the results. In the study of 273 cases of B- or T-cell lymphomas with characteristic immunomorphological and clinical features, a clonal IgH or TcR-γ chain gene rearrangement was detected in approximately 80% of cases. A clonal rearrangement involving both IgH and TcR-γ chain genes was found in 10% of cases of both B-cell and T-cell lymphomas. The study of 167 cases of nonneoplastic lymphoid tissue samples showed the presence of clonally rearranged cell populations for IgH or TcR-γ genes in 3 and 9% of cases, respectively. We also applied PCR for the study of 85 cases of lymphoproliferations with no definite diagnosis (i.e., benign versus malignant) after immunomorphological analysis. In 65 cases (76%), the correlation of immunomorphological features with the presence (48 cases) or the absence (17 cases) of clonal lymphoid cell populations led to a definite diagnosis. In almost all these cases, the final diagnosis was found to be in agreement with the clinical course. In the 20 remaining cases (24%), no definite diagnosis could be made. We also assessed the value of PCR in detecting bcl-2/JH gene rearrangement as an additional clonal marker in the diagnosis of follicular lymphoma. Bcl-2/JH rearrangement and/or IgH gene rearrangement was found in approximately 85% (71/85) of follicular lymphoma cases studied.

Impact of the Methotrexate Administration Dose on the Need for Intrathecal Treatment in Children and Adolescents With Anaplastic Large-Cell Lymphoma: Results of a Randomized Trial of the EICNHL Group

PURPOSE To compare the efficacy and safety of two methotrexate doses and administration schedules in children with anaplastic large-cell lymphoma (ALCL). PATIENTS AND METHODS This randomized trial for children with ALCL was based on the Non-Hodgkins Lymphoma-Berlin-Frankfurt-Muenster 90 (NHL-BFM90) study protocol and compared six courses of methotrexate 1 g/m2 over 24 hours and an intrathecal injection (IT) followed by folinic acid rescue at 42 hours (MTX1 arm) with six courses of methotrexate 3 g/m2 over 3 hours followed by folinic acid rescue at 24 hours without IT (MTX3 arm). This trial involved most European pediatric/lymphoma study groups and a Japanese group. RESULTS Overall, 352 patients (96% ALK positive) were recruited between 1999 and 2005; 175 were randomly assigned to the MTX1 arm, and 177 were assigned to the MTX3 arm. Ninety-two percent of patients received protocol treatment. Median follow-up time is 3.7 years. Event-free survival (EFS) curves were superimposed with 2-year EFS rates (73.6% and 74.5% in the MTX1 and MTX3 arms, respectively; hazard ratio = 0.98; 91.76% CI, 0.69 to 1.38). Two-year overall survival rates were 90.1% and 94.9% in MTX1 and MTX3, respectively. Only two CNS relapses occurred (both in the MTX1 arm). Toxicity was assessed after 2,050 courses and included grade 4 hematologic toxicity after 79% and 64% of MTX1 and MTX3 courses, respectively (P < .0001); infection after 50% and 32% of courses, respectively (P < .0001); and grade 3 to 4 stomatitis after 21% and 6% of courses, respectively (P < .0001). CONCLUSION The results of the NHL-BFM90 study were reproduced in this large international trial. The methotrexate schedule of the NHL-BFM90 protocol including IT therapy can be safely replaced by a less toxic schedule of methotrexate 3 g/m2 in a 3-hour infusion without IT therapy.

Anaplastic Lymphoma Kinase–Positive Diffuse Large B-Cell Lymphoma: A Rare Clinicopathologic Entity With Poor Prognosis

PURPOSE Anaplastic lymphoma kinase (ALK) -positive diffuse large B-cell lymphoma (DLBCL) is a rare variant of DLBCL that has been described only in small case reports. To shed more light on the clinical and pathologic features and outcome of these tumors, we reviewed data from 38 patients. PATIENTS AND METHODS We retrospectively analyzed 38 patients with ALK-positive DLBCL treated with cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) or CHOP-like regimens from different institutions to better define the presenting features, clinical course, and response to treatment. RESULTS The histologic findings in all patients were similar. All patients expressed ALK fusion proteins, but virtually all were CD30 and CD20 negative. The median age was 43 years with a 5:1 ratio of males to females. Most patients (60%) followed an aggressive clinical course with advanced stage at diagnosis, frequent marrow infiltration, and poor outcome. Overall survival was 20.3 months (95% CI, 12.2 to 42.6 months). Of note, the median survival was only 12.2 months (95% CI, 9.1 to 32.5 months) in patients with advanced-stage disease. CONCLUSION ALK-positive DLBCLs display clinicopathologic features that distinguish them from common DLBCL. Conventional therapy, as used for typical DLBCL, is of limited efficacy. Recognition of this new entity and the characteristic lack of CD20 expression are paramount. Novel front-line intensive chemotherapy regimens should be evaluated in this group of patients.

Non-muscle myosin heavy chain (MYH9): a new partner fused to ALK in anaplastic large cell lymphoma.

In anaplastic large cell lymphoma, the ALK gene at 2p23 is known to be fused to NPM, TPM3, TPM4, TFG, ATIC, CLTC, MSN, and ALO17. All of these translocations result in the expression of chimeric ALK transcripts that are translated into fusion proteins with tyrosine kinase activity and oncogenic properties. We report a case showing a restricted cytoplasmic staining pattern of ALK and a novel chromosomal abnormality, t(2;22)(p23;q11.2), demonstrated by fluorescence in situ hybridization analysis. The result of 5′ RACE analysis showed that the ALK gene was fused in‐frame to a portion of the non‐muscle myosin heavy chain gene, MYH9. Nucleotide sequence of the MYH9‐ALK chimeric cDNA revealed that the ALK breakpoint was different from all those previously reported. It is localized in the same exonic sequence as MSN‐ALK, but 6 bp downstream, resulting in an in‐frame fusion of the two partner proteins. In contrast to the previously reported ALK fusion proteins, MYH9‐ALK may lack a functional oligomerization domain. However, biochemical analysis showed that the new fusion protein is tyrosine phosphorylated in vivo but seems to lack tyrosine kinase activity in vitro. If further investigations confirm this latter result, the in vivo tyrosine phosphorylation of MYH9‐ALK protein could involve mechanisms different from those described in the other ALK hybrid proteins.

Differential effects of X-ALK fusion proteins on proliferation, transformation, and invasion properties of NIH3T3 cells.

Majority of anaplastic large-cell lymphomas (ALCLs) are associated with the t(2;5)(p23;q35) translocation, fusing the NPM (nucleophosmin) and ALK (anaplastic lymphoma kinase) genes (NPM-ALK). Recent studies demonstrated that ALK may also be involved in variant translocations, namely, t(1;2)(q25;p23), t(2;3)(p23;q21), t(2;17)(p23;q23) and inv(2)(p23q35), which create the TPM3-ALK, TFG-ALK5, CLTC-ALK, and ATIC-ALK fusion genes, respectively. Although overexpression of NPM-ALK has previously been shown to transform fibroblasts, the transforming potential of variant X-ALK proteins has not been precisely investigated. We stably transfected the cDNAs coding for NPM-ALK, TPM3-ALK, TFG-ALK, CLTC-ALK or ATIC-ALK into nonmalignant NIH3T3 cells. All X-ALK variants are tyrosine phosphorylated and their subcellular distribution was in agreement with that observed in tumors. Moreover, our results show that the in vitro transforming capacity of NIH3T3-transfected cells are in relation to the level of X-ALK fusion proteins excepted for TPM3-ALK for which there is an inverse correlation. The differences between the five X-ALK variants with regard to proliferation rate, colony formation in soft agar, invasion, migration through the endothelial barrier and tumorigenicity seem to be due to differential activation of various signaling pathways such as PI3-kinase/AKT. These findings may have clinical implications in the pathogenesis and prognosis of ALK-positive ALCLs.

Single-Drug Vinblastine As Salvage Treatment for Refractory or Relapsed Anaplastic Large-Cell Lymphoma: A Report From the French Society of Pediatric Oncology

PURPOSE To evaluate the efficacy of vinblastine for relapsed/refractory anaplastic large-cell lymphoma (ALCL). PATIENTS AND METHODS Data were reviewed on all 36 patients included prospectively in the French database for pediatric ALCL who were treated with vinblastine (6 mg/m(2)/wk) for resistant primary disease (one), a first relapse (15), or subsequent relapses (20). Fifteen patients had undergone hematopoietic stem-cell transplantation (HSCT) for a previous relapse. RESULTS Six patients were not evaluable for response, 25 (83%) of 30 evaluable patients achieved a complete remission (CR), and five experienced progressive disease. Among the 31 patients who achieved a CR with vinblastine or before its initiation, six patients were treated with HSCT and 25 with vinblastine alone (median duration, 14 months). Overall, nine of 25 patients treated with vinblastine alone have remained in CR (median, 7 years since the end of treatment), and 16 patients have relapsed. Vinblastine was still efficient for subsequent relapses. With a median follow-up of 9.2 years, 12 patients have died (four as a result of toxicity after HSCT and eight as a result of disease), and 24 patients are alive (15 following treatment with single-agent vinblastine for the last event). Five-year overall survival is 65% (95% CI, 48% to 79%), and 5-year event-free survival is 30% (95% CI, 17% to 47%). CONCLUSION Vinblastine is highly efficient in relapsed ALCL and may produce durable remissions. The optimal treatment duration still has to be assessed. These results should be borne in mind when designing future phase II studies with the targeted therapies directed against anaplastic lymphoma kinase.

Oncogenic protein tyrosine kinases

Abstract.Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase, the normal role of which remains to be completely elucidated. Although work carried out in mammals suggests a function in neural development, results from studies in Drosophila indicate an additional role in visceral muscle differentiation. The aberrant expression of full-length ALK receptor proteins has been reported in neuroblastomas and glioblastomas, while the occurrence of ALK fusion proteins in anaplastic large cell lymphoma (ALCL) has resulted in the identification of the new tumor entity, ALK-positive ALCL. ALK represents one of few examples of a receptor tyrosine kinase implicated in oncogenesis in both haematopoietic and non-haematopoietic tumors, given that ALK fusions also occur in the mesenchymal tumor known as inflammatory myofibroblastic tumor (IMT). The study of ALK fusion proteins, besides demonstrating their importance in tumor development, has also raised the possibility of new therapeutic treatments for patients with ALK-positive malignancies.