Jacky Ferrer

Expression of neurotrophins and their receptors in human bone marrow.

The expression of neurotrophins and their receptors, the low-affinity nerve growth factor receptor (p75LNGFR) and the Trk receptors (TrkA, TrkB, and TrkC), was investigated in human bone marrow from 16 weeks fetal age to adulthood. Using reverse transcription-polymerase chain reaction, all transcripts encoding for catalytic and truncated human TrkB or TrkC receptors were detected together with trkAI transcripts, whereas trkAII transcripts were found only in control nerve tissues. Transcripts for the homologue of the rat truncated TrkC(ic113) receptor were identified for the first time in human tissue. Stromal adventitial reticular cells were found immunoreactive for all neutrophin receptors. In contrast, hematopoietic cell types were not immunoreactive for p75LNGFR but showed immunoreactivity for one or several Trk receptors. TrkA immunoreactivity was found in immature erythroblasts. Catalytic TrkB immunoreactivity was observed in eosinophilic metamyelocytes and polymorphonuclear cells. Truncated TrkB immunoreactivity was found in erythroblasts and megacaryocytes. Immunoreactivity for both catalytic and truncated TrkC receptor was observed in promyelocytes, myelocytes, some polymorphonuclear cells and megacaryocytes. Neutrophin transcript levels appeared higher at fetal than at adult stages, no variation in Trk family transcript levels was observed. The local expression of neurotrophin genes suggests a wide range of paracrine and/or autocrine mode of action through their corresponding receptors within the bone marrow.

Inactivation of p16INK4a/CDKN2A gene may be a diagnostic feature of large B cell lymphoma leg type among cutaneous B cell lymphomas

The World Health Organization–European Organization for Research and Treatment of Cancer has individualized three main categories among the primary cutaneous B cell lymphoma (PCBCL): leg-type primary cutaneous large B cell lymphoma (PCLBCL leg type), primary cutaneous follicle center lymphoma (PCFCL), and primary cutaneous marginal zone lymphoma (PCMZL). The genetic features of 21 PCBCL cases (six PCLBCL leg type four PCFCL large cells, seven PCFCL small cells, and four PCMZL) were investigated by comparative genomic hybridization (CGH array). Fluorescent in situ hybridization (FISH) analysis was performed to confirm CGH array data and to detect lymphoma-associated gene rearrangements. p14ARF/p16INK4aCDKN2A gene quantification, methylation analysis, and immunohistochemical detection were also performed. CGH array showed a higher number of recurrent genetic imbalances in PCLBCL leg type (mean 62) than in PCFCL large cells (mean 34). PCFCL small cells and PCMZL exhibited fewer chromosomal alterations (mean 24 and 9). FISH analysis provided concordant results with CGH array data in 97% (98 of 101) assays and demonstrated a t(8;14)(q24;q32) in two of six PCLBCL leg type. Recurrent deletions in 9p21 (p14ARF/p16INK4aCDKN2A) were a constant finding in PCLBCL leg type (six of six). Conversely, PCFCL large cells exhibited recurrent 1p36 deletions (four of four) without deletion in 9p21 (zero of four). The diagnostic and prognostic impact of the p16INK4aCDKN2A gene status in PCBCL should therefore be confirmed on a larger series.

The detection of Tel–TrkC chimeric transcripts is more specific than TrkC immunoreactivity for the diagnosis of congenital fibrosarcoma

The t(12;15)(p13;q25) translocation, a recurrent chromosomal abnormality of congenital fibrosarcoma, leads to the expression of a Tel–TrkC fusion transcript. To determine whether detection of the chimeric protein may be helpful for the diagnosis of congenital fibrosarcoma, immunohistochemistry was performed with an anti‐TrkC antibody on 26 spindle cell tumours of newborn or young children (n=19) or adults (n=7). Four out of five congenital fibrosarcomas showed TrkC immunoreactivity with cytoplasmic paranuclear staining. However, TrkC immunoreactivity was not restricted to congenital fibrosarcoma and was observed in infantile myofibromatosis, congenital haemangiopericytoma, desmoid tumour, nodular fasciitis, fibrous hamartoma, inflammatory myofibroblastic tumour, and adult fibrosarcoma. RT‐PCR analysis was performed on nine cases, including four congenital fibrosarcomas, for which frozen material was available. Tel–TrkC transcripts were detected by RT‐PCR in the four congenital fibrosarcomas analysed, but not in the five other spindle cell tumours. Furthermore, several Tel–TrkC transcripts encoding for kinase isoforms of the Tel–TrkC protein were detected in congenital fibrosarcoma and may be involved in oncogenesis. The reciprocal TrkC–Tel transcript was detected in only one congenital fibrosarcoma. While the detection of a Tel–TrkC fusion transcript is a recurrent feature of congenital fibrosarcoma, TrkC immunoreactivity does not appear specific for the diagnosis of fibromatous paediatric tumours. Copyright

Bone Marrow Histopathologic and Molecular Staging in Epidermotropic T-Cell Lymphomas

This study was undertaken to determine the prognostic value of bone marrow histopathologic and molecular analyses in 53 patients with mycosis fungoides and 7 with Sézary syndrome. Bone marrow was involved in only 1 patient with Sézary syndrome, clinical stage IVA, before bone marrow biopsy. An ambiguous T-cell infiltrate was observed in 8 patients but was not associated with disease progression. The bone marrow specimen was normal in 51 patients. Monoclonality was detected in the skin specimen in 44 cases; an identical T-cell clone in the blood specimen was found in 21 of them and, in 16 of the 21 patients, in bone marrow specimens without histologic correlation. Multivariate analysis confirmed that clinical stage and detection by polymerase chain reaction of an identical T-cell clone in skin and blood specimens had an independent prognostic value. No further prognostic value was observed for the presence of a T-cell clone in bone marrow specimens. Our data do not support the need for bone marrow examination in patients with mycosis fungoides/Sézary syndrome.

Combined analysis of T cell receptor γ and immunoglobulin heavy chain gene rearrangements at the single-cell level in lymphomas with dual genotype

By prospectively studying immunoglobulin heavy chain gene (IgH) and T cell receptor gamma (TCRγ) gene rearrangements in 398 lymphoma cases, a dual genotype was observed in 13% of B cell and 11% of T cell lymphomas. According to histological subtype, the highest incidence was observed for mantle cell lymphomas (32%) and lymphoplasmacytic lymphoma (21%) among B cell lymphomas, and for angioimmunoblastic lymphoma (AILT) (46%) and Sézary syndrome (SS) (50%) among T cell lymphomas. To determine whether the dual genotype corresponds to the presence of two distinct monoclonal populations or to the presence of both rearrangements within the same lymphoma cells, single‐cell microdissection was used after immunohistochemistry and a single‐cell combined IgH and TCRγ gene analysis was designed after a whole‐genome amplification step. This protocol was applied to the study of two nodal B cell lymphomas (one diffuse large B cell lymphoma and one mantle cell lymphoma) and two cutaneous T cell lymphomas (one AILT and one SS). Two cases (SS and mantle cell lymphoma) were true bigenotypic lymphomas, as both IgH and TCRγ monoclonal rearrangements were detected in the same cells. Conversely, in the diffuse large B cell lymphoma and AILT cases, large CD22+ single cells exhibited only the monoclonal IgH rearrangement but not the TCRγ gene that was detected in CD3+ single cells. Such an approach allows the identification of true bigenotypic lymphoma among dual genotypic lymphoma. Specific genetic alterations may be further amplified from microdissected cryopreserved material, such as the t(11;14) breakpoint detected in bigenotypic B cells of the mantle cell lymphoma case. Copyright

Chromosomal imbalances: a hallmark of tumour relapse in primary cutaneous CD30+ T-cell lymphoma

Primary cutaneous CD30+ large T‐cell lymphoma (CD30+ CTCL) is a subset of non‐epidermotropic primary cutaneous T‐cell lymphoma. Although frequent spontaneous regression may be observed, skin relapses occur frequently. Cytogenetic abnormalities that could play a role in CD30+ CTCL tumour pathogenesis and relapses remain unknown. The identification of recurrent cytogenetic abnormalities is hampered by difficulty in culturing tumours and the lack of CD30+ CTCL serial studies comparing genetic changes both at diagnosis and at relapse. The purpose of this study was to investigate the cytogenetic abnormalities present in a series of 13 CD30+ CTCL samples obtained from nine patients fulfilling both EORTC and WHO diagnostic criteria, by the use of comparative genomic hybridization (CGH). CGH analysis revealed a non‐random distribution of genetic imbalances between relapsing and non‐relapsing disease. In relapsing disease, chromosomal abnormalities were detected both in the primary tumour and in relapses. The mean number of changes in non‐relapsing disease was 0.33 (range 0–1), compared with 6.29 (range 1–16) in relapsing disease. The recurrent chromosomes involved in relapsing disease were chromosomes 6 (86%), 9 (86%), and 18 (43%). While chromosome 9 was mostly affected by gain, chromosomes 6 and 18 mainly contained regions of loss, exclusively on 6q and 18p. The common regions of deletion were 6q21 and 18p11.3. In one patient, we successfully cultured tumour cells from a skin biopsy from a second relapse. The G‐banded karyotype was concordant with both CGH and fluorescence in situ hybridization (FISH) results. Although further studies are required to strengthen these data, this CGH analysis demonstrates chromosomal imbalances that may be involved in the pathogenesis of relapsing CD30+ CTCL. Copyright

Benign lymphocytic angiitis and granulomatosis: A T-cell lymphoma?

Benign lymphocytic angiitis and granulomatosis is a T-cell lymphoproliferative disorder confined to the lung and corresponding to a low-grade angiocentric immunoproliferative lesion. Controversy remains as to whether these lesions are lymphomas. We report such a case in an 8-year-old patient with Burkitts lymphoma in remission who presented with persistent bronchopneumopathy and bilateral pulmonary infiltrates on tomodensitometry. Surgical resection revealed the histologic changes of benign lymphocytic angiitis and granulomatosis. Immunohistochemistry showed no aberrant pan T-cell marker loss. Genetic analysis of frozen tissue by Southern blot DNA hybridization with probes to T-cell receptor beta- and gamma-chain genes and to the immunoglobulin heavy chain joining region gene (JH) identified no clonal rearrangement. Search for Epstein-Barr virus-DNA sequences by in situ hybridization and Southern blot analysis provided negative results. Our data imply that lowgrade angiocentric immunoproliferative lesions are not exclusively lymphomas but might represent a borderline lymphoproliferative disease (seen in the course of many diseases), perhaps corresponding to host immune response.