ID: 1023 All-trans retinoic acid targets gastric cancer stem cells and inhibits patient-derived gastric carcinoma tumor growth

Gastric carcinoma is the third leading cause of cancer-related death worldwide. This cancer, most of the time metastatic, is essentially treated by surgery associated with conventional chemotherapy, and has a poor prognosis. The existence of cancer stem cells (CSC) expressing CD44 and a high aldehyde dehydrogenase (ALDH) activity has recently been demonstrated in gastric carcinoma and has opened new perspectives to develop targeted therapy. In this study, we evaluated the effects of all-transretinoic acid (ATRA) on CSCs in human gastric carcinoma. ATRA effects were evaluated on the proliferation and tumorigenic properties of gastric carcinoma cells from patient-derived tumors and cell lines in conventional 2D cultures, in 3D culture systems (tumorsphere assay) and in mouse xenograft models. ATRA inhibited both tumorspheres initiation and growth in vitro, which was associated with a cell-cycle arrest through the upregulation of cyclin-dependent kinase (CDK) inhibitors and the downregulation of cell-cycle progression activators. More importantly, ATRA downregulated the expression of the CSC markers CD44 and ALDH as well as stemness genes such as Klf4 and Sox2 and induced differentiation of tumorspheres. Finally, 2 weeks of daily ATRA treatment were sufficient to inhibit gastric tumor progression in vivo, which was associated with a decrease in CD44, ALDH1, Ki67 and PCNA expression in the remaining tumor cells. Administration of ATRA appears to be a potent strategy to efficiently inhibit tumor growth and more importantly to target gastric CSCs in both intestinal and diffuse types of gastric carcinoma.

An essential role for Ink4 and Cip/Kip cell-cycle inhibitors in preventing replicative stress

Cell-cycle inhibitors of the Ink4 and Cip/Kip families are involved in cellular senescence and tumor suppression. These inhibitors are individually dispensable for the cell cycle and inactivation of specific family members results in increased proliferation and enhanced susceptibility to tumor development. We have now analyzed the consequences of eliminating a substantial part of the cell-cycle inhibitory activity in the cell by generating a mouse model, which combines the absence of both p21(Cip1) and p27(Kip1) proteins with the endogenous expression of a Cdk4 R24C mutant insensitive to Ink4 inhibitors. Pairwise combination of Cdk4 R24C, p21-null and p27-null alleles results in frequent hyperplasias and tumors, mainly in cells of endocrine origin such as pituitary cells and in mesenchymal tissues. Interestingly, complete abrogation of p21(Cip1) and p27(Kip1) in Cdk4 R24C mutant mice results in a different phenotype characterized by perinatal death accompanied by general hypoplasia in most tissues. This phenotype correlates with increased replicative stress in developing tissues such as the nervous system and subsequent apoptotic cell death. Partial inhibition of Cdk4/6 rescues replicative stress signaling as well as p53 induction in the absence of cell-cycle inhibitors. We conclude that one of the major physiological activities of cell-cycle inhibitors is to prevent replicative stress during development.

Lack of beta-catenin in early life induces abnormal glucose homeostasis in mice

AIMS/HYPOTHESIS

Wingless and iNT-1 (WNT) pathway members are critical for pancreatic development and exocrine tissue formation. Recently, much attention has focused on delineating the roles of beta-catenin in pancreatic organogenesis. However, little is known about the involvement of beta-catenin in the endocrine or exocrine function of the mature pancreas. We report for the first time the impact of beta-catenin deletion in the pancreatic beta cells.

METHODS

We targeted the deletion of the beta-catenin gene in pancreatic beta cells by crossing a floxed beta-catenin mouse strain with a RIP-Cre mouse strain.

RESULTS

Surprisingly, the majority of the mutant mice died shortly after birth and had deregulated glucose and insulin levels. The newborn mutant pancreases demonstrated increased insulin content, reflecting a defect in insulin release confirmed in vitro. Moreover, there was a reduction in total endocrine tissue at birth, while cellularity in islets was greater, suggesting that lack of beta-catenin affects beta cell size. Some newborns survived beta-catenin deletion and showed a milder phenotype during adulthood.

CONCLUSIONS/INTERPRETATION

The deletion of beta-catenin in the maturing beta cells negatively impacts on islet morphology and function. This work reveals that lack of beta-catenin in early life is related to severe deregulation of glucose homeostasis.

Progress in updating the European Radiobiology Archives

PURPOSE

The European Radiobiology Archives (ERA), together with corresponding Japanese and American databases, hold data from nearly all experimental animal radiation biology studies carried out between 1960 and 1998, involving more than 300,000 animals. The Federal Office for Radiation Protection, together with the University of Cambridge have undertaken to transfer the existing ERA archive to a web-based database to maximize its usefulness to the scientific community and bring data coding and structure of this legacy database into congruence with currently accepted semantic standards for anatomy and pathology.

METHODS

The accuracy of the primary data input was assessed and improved. The original rodent pathology nomenclature was recoded to replace the local 'DIS-ROD' (Disease Rodent) formalism with Mouse Pathology (MPATH) and Mouse Anatomy (MA) ontology terms. A pathology panel sampled histopathological slide material and compared the original diagnoses with currently accepted diagnostic criteria.

RESULTS

The overall non-systematic error rate varied among the studies between 0.26% and 4.41%, the mean error being 1.71%. The errors found have been corrected and the studies thus controlled have been annotated. The majority of the original pathology terms have been successfully translated into a combination of MPATH and MA ontology terms.

CONCLUSIONS

ERA has the potential of becoming a world-wide radiobiological research tool for numerous applications, such as the re-analysis of existing data with new approaches in the light of new hypotheses and techniques, and using the database as an information resource for planning future animal studies. When the database is opened for new data it may be possible to offer long-term storage of data from recent and future animal studies.

Genetic cooperation between p21Cip1 and INK4 inhibitors in cellular senescence and tumor suppression

Cell-cycle inhibitors of the Cip/Kip and INK4 families are involved in cellular senescence and tumor suppression. Some of these proteins, p21(Cip1), p16(INK4a) and p15(INK4b), are coexpressed in response to antiproliferative signals such as cellular senescence resulting in cell-cycle arrest. To understand the roles of these inhibitors and their synergistic effect, we have characterized the growth properties and senescent behavior of primary cells deficient in p21(Cip1) and expressing an endogenous Cdk4(R24C) (cyclin-dependent kinase) mutant (Cdk4(R24C) knock-in cells) insensitive to INK4 proteins. Inactivation of both p21(Cip1) and INK4 pathways strongly cooperate in suppressing cellular senescence in vitro. These double mutant cells behavior as immortal cultures and display high sensitivity to cellular transformation by oncogenes. Moreover, mice double mutant in the INK4 and p21(Cip1) pathways (Cdk4(R24C); p21(Cip1)-null mice) display an increased incidence of specific sarcomas, suggesting a significant cooperation between these two families of cell-cycle inhibitors in senescence responses and tumor suppression in vivo.

Splitting bone marrow trephines into frozen and fixed fragments allows parallel histological and molecular detection of B cell malignant infiltrates

Clonality analysis of the immunoglobulin heavy chain (IgH) gene is helpful in identifying malignant B cell infiltrates in the bone marrow and is usually carried out on separate aspirates or on the same formalin-fixed decalcified bone marrow specimen. To determine whether the removal of the decalcification step would improve the molecular analysis, we first studied 12 bone marrow specimens with lymphoma infiltration split into a fixed and a small frozen fragment. Both the detection rate of IgH gene monoclonality and DNA quality were found to be superior in the frozen part than in the fixed part. Conversely, to evaluate whether the split would compromise histological analysis, we selected a series of 134 bone marrow specimens obtained from patients with small B cell lymphoma and showing IgH monoclonality on the frozen part. The histological detection rate of infiltrated or suspicious infiltrates (95%) on the fixed part was not altered by saving a frozen part.

Cell cycle and cancer: genetic analysis of the role of cyclin-dependent kinases

Most human tumors harbor mutations that misregulate the early phases of the cell cycle. Here, we summarize genetic evidence, mostly obtained in our laboratory using strains of gene-targeted mice, that provides direct experimental support for a role of Cdk4 in tumor development. Moreover, these genetic studies challenge some well-established concepts regarding the role of Cdks during the early phases of the cell cycle. For instance, they have illustrated that Cdk4 and Cdk6 are not essential for cell division during embryonic development except in the hematopoietic system. More surprisingly, mice lacking Cdk2 survive for over 2 years without detectable abnormalities except in their germ cells, indicating that Cdk2 is essential for meiosis but dispensable for the normal mitotic cell cycle. Cdk2 is also dispensable for cell cycle inhibition and tumor suppression by the Cip/Kip inhibitors, p21(Cip1) and p27(Kip1). These observations have important implications not only to understand cell cycle regulation, but also to validate Cdks as potential targets for the development of therapeutic strategies to block proliferation of tumor cells.

Blastoid and common variants of mantle cell lymphoma exhibit distinct immunophenotypic and interphase FISH features

AIMS

The recognition of blastoid variant (BV) of mantle cell lymphoma (MCL) is based on morphological criteria. Our aim was to analyse 18 MCL cases including four BV-MCL for their clinicopathological features, proliferation index, cyclin D1 and CDK4 expression and interphase fluorescence in-situ hybridization (FISH) pattern.

METHODS AND RESULTS

BV-MCL versus common MCL was characterized by a shorter overall duration of response after first-line therapy (11 months versus 28 months) and shorter overall survival (20 months versus 42 months). Interphase FISH showed a t(11;14) fusion pattern in all MCL tested cases. However, the four blastoid cases were characterized by extra copies of CCND1 signals. Using additional probes of chromosomes 11, 18, 21, these signals were shown to be the result of hypotetraploidy and not of a specific amplification of the normal or the translocated CCND1 allele. Moreover, the BV-MCL cases were characterized by a combined high percentage of cells expressing cyclin D1 and/or CDK4 with a proliferation (MIB-1-Ki67) index above 50%. Such features allowed the recognition of areas of large cell transformation in the case of secondary BV-MCL.

CONCLUSIONS

Since distinction between BV and common MCL is of clinical relevance, our data underline the need to add phenotypic and cytogenetic criteria to cytomorphology for a better recognition of BV-MCL.

A knock-in mouse model of congenital erythropoietic porphyria

Congenital erythropoietic porphyria (CEP) is a recessive autosomal disorder characterized by a deficiency in uroporphyrinogen III synthase (UROS), the fourth enzyme of the heme biosynthetic pathway. The severity of the disease, the lack of specific treatment except for allogeneic bone marrow transplantation, and the knowledge of the molecular lesions are strong arguments for gene therapy. An animal model of CEP has been designed to evaluate the feasibility of retroviral gene transfer in hematopoietic stem cells. We have previously demonstrated that the knockout of the Uros gene is lethal in mice (Uros(del) model). This work describes the achievement of a knock-in model, which reproduces a mutation of the UROS gene responsible for a severe UROS deficiency in humans (P248Q missense mutant). Homozygous mice display erythrodontia, moderate photosensitivity, hepatosplenomegaly, and hemolytic anemia. Uroporphyrin (99% type I isomer) accumulates in urine. Total porphyrins are increased in erythrocytes and feces, while Uros enzymatic activity is below 1% of the normal level in the different tissues analyzed. These pathological findings closely mimic the CEP disease in humans and demonstrate that the Uros(mut248) mouse represents a suitable model of the human disease for pathophysiological, pharmaceutical, and therapeutic purposes.

Leukemic dissemination within a glioblastoma in a patient with chronic lymphoid leukemia

Metastasis from an extracranial tumor to a primary central nervous system tumor is a rare event, and most reported cases concern metastases to meningiomas. The authors describe the first case of leukemic cell dissemination within a glioblastoma. The patient likely presented a genetic predisposition to multiple neoplasms, and the unusual localization of leukemic cells might be partly related to the characteristic microvascular proliferation in glioblastoma.

Combined analysis of T cell receptor gamma 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 (TCRgamma) 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 TCRgamma 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 TCRgamma 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 TCRgamma 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.

Invasive melanoma in Cdk4-targeted mice

Many human tumors harbor mutations that result in deregulation of Cdk4 activity. Most of these mutations involve overexpression of D-type cyclins and inactivation of INK4 inhibitors. In addition, a mutation in the Cdk4 protein has been described in patients with familial melanoma (Wolfel, T., Hauer, M., Schneider, J., Serrano, M., Wolfel, C., et al. (1995) Science 269, 1281-1284; Zuo, L., Weger, J., Yang, Q., Goldstein, A. M., Tucker, M. A., et al. (1996) Nat. Genet. 12, 97-99). This mutation, R24C, renders the Cdk4 protein insensitive to inhibition by INK4 proteins including p16(INK4a), a major candidate for the melanoma susceptibility locus. Here we show that knock-in mice expressing a Cdk4 R24C allele are highly susceptible to melanoma development after specific carcinogenic treatments. These tumors do not have mutations in the p19(ARF)/p53 pathway, suggesting a specific involvement of the p16(INK4a)/Cdk4/Rb pathway in melanoma development. Moreover, by using targeted mice deficient for other INK4 inhibitors, we show that deletion of p18(INK4c) but not of p15(INK4b) confers proliferative advantage to melanocytic tumor growth. These results provide an experimental scenario to study the role of Cdk4 regulation in melanoma and to develop novel therapeutic approaches to control melanoma progression.

Evidence that an identical T cell clone in skin and peripheral blood lymphocytes is an independent prognostic factor in primary cutaneous T cell lymphomas

The monoclonality of the T cell receptor gamma-chain gene was analyzed by polymerase chain reaction in skin and blood specimens of 85 patients with cutaneous T cell lymphomas including 67 mycosis fungoides, seven Sézary syndromes, and 11 CD30- nonepidermotropic cutaneous T cell lymphomas. A cutaneous T cell clone was detected in 69% of mycosis fungoides and 100% of Sézary syndromes. This frequency varied according to the clinical stage: 57% in early stages (Ia-IIa) to 96% in advanced stages (IIb-IV, Sézary syndrome). A peripheral blood T cell clone was detected in 42% of early stages and in 74% of late stages but was identical to the cutaneous one in 15% and in 63%, respectively. A significant association between initial clinical stage and T cell monoclonality was observed. In nonepidermotropic cutaneous T cell lymphomas, T cell monoclonality was detected in 55% of skin and 36% of blood samples. Univariate and multivariate analyses showed that, besides the initial clinical stage, an identical cutaneous and blood T cell clone was an independent prognostic factor for disease progression of mycosis fungoides/Sézary syndrome (hazard ratio 3.4, 95% confidence interval 1.4-9.9). Parallel polymerase chain reaction study of skin and blood specimens may therefore provide an initial prognostic marker that could help to monitor therapeutic strategies. A fully prospective study, with simultaneous therapeutic trials, needs to be done to confirm our findings and to include treatment variables in the statistical analysis.

[Infantile fibrosarcoma: a clinicopathological and molecular study of five cases]

We report 5 cases of infantile fibrosarcoma (4 boys and 1 girl) whose average age was 5, 7 months (range 0 days to 14 months). The tumor was congenital in 4 cases. All tumors presented in the extremities (forearm, hand, thigh: 1 case, lower leg: 2 cases). Treatment was based on surgery (3 cases: amputation, 2 cases: local excision) with a favorable course in all cases, even those with marginal excision (follow-up ranging from 5 to 21 years). The lesions were characterized by dense monotonous cells growing in a fascicular pattern, with small necrotic areas and scattered lymphocytes. The mitotic index was high (average 8/10 high-power fields). ETV6-NK3 chimeric RNA was detected by reverse transcriptase polymerase chain reaction in two cases out four cases from paraffin-embedded tissue blocks. The infantile fibrosarcoma is a good prognosis tumor characterized by particular histological features and ETV6-NK3 gene fusion.

[Interphase FISH analysis of frozen or fixed tissues for the detection of t(11;14) (q13;q32) in mantle cell lymphoma]

Cytogenetic analyses have revealed that mantle cell lymphomas (MCL) are closely associated with the t(11;14)(q13;q32). This translocation juxtaposes the immunoglobulin heavy chain gene (IGH) sequences with the BCL-1 locus, leading to up-regulation of the CCND1 gene and consequently to an overexpression of cyclin D1 protein. We studied 27 MCL with characteristic morphological and immunological (CD5+, CD10-, CD20+, CD23-) features and 2 controls (reactionnal lymphadenitis) to evaluate the feasibility and the interest of FISH analysis on interphase cells from frozen or paraffin-embedded tissues. Sections (CC) and touch preparations (EC) of frozen tissues and sections of paraffin-embedded tissues (CF) were successfully hybridized with the Vysis LSI IgH/CCND1 dual color dual fusion translocation probe. The touch preparations presented a lower cellularity than sections, therefore allowing an easier analysis. Hybridization spots intensities were found stronger in CC and EC than in CF. The percentages of t(11;14) positive cells were similar in CC, EC and CF from a same patient. The percentage of non hybridized cells, analogous in CC and EC, was higher in CF. However, the CF were directly analysed on microscope without the need of any numerical picture treatment. The t(11;14) was detected in all the cases (27/27) and positive cells percentages were always higher than the probe cut-off (5%). The FISH analysis on interphase cells appears a performing and rapid technique to detect t(11;14) in MCL on both frozen and paraffin-embedded tissue, thus extending its practical and diagnostic use.

True histiocytic lymphoma following B-acute lymphoblastic leukaemia: case report with evidence for a common clonal origin in both neoplasms

True histiocytic lymphoma (THL) is a very rare type of non-Hodgkin's lymphoma (NHL) in which neoplastic cells exhibit markers of histiocytic differentiation. Some cases of THL have been reported in patients with previous acute lymphoblastic leukaemia (ALL), especially in children and young adults, in whom the acute leukaemia was of T-cell origin. The relationship between the initial lymphoid tumour and the secondary THL remains unclear, as a common monoclonal origin shared by both neoplasms has never been definitively demonstrated. We report a patient with B-ALL who developed a nodal and extranodal tumour with histological and immunohistochemical features of THL 4 years after the initial diagnosis. Genotypic study showed that both neoplasms contained the same immunoglobulin heavy gene rearrangement, which has not been reported previously.

Sodium valproate-induced cutaneous pseudolymphoma followed by recurrence with carbamazepine

We report a patient with a sodium valproate-induced cutaneous pseudolymphoma, presenting with an erythematous papule, histologically mimicking a non-epidermotropic T-cell lymphoma. Polymerase chain reaction study of the skin biopsy revealed monoclonal rearrangement of the T-cell receptor gamma gene. Withdrawal of sodium valproate was followed by regression of the lesion, but 5 months after substitution by carbamazepine, two further papules appeared, with similar histological features and a T-cell clone identical to the initial one. Carbamazepine was stopped and the lesions disappeared without relapse over a 4-year follow-up. Sodium valproate is very rarely responsible for a hypersensitivity syndrome, and our case is the first report of sodium valproate-induced cutaneous pseudolymphoma. The recurrence with carbamazepine may be due to a common effect on T-cell lymphocyte function. The return of the same monoclonal population shows that the recurrence of monoclonal T cells may be observed in benign conditions and is not an exclusive hallmark of cutaneous lymphoma.

Primary Digestive Richter's Syndrome

The clinical and morphologic transformation of 3 to 5% of chronic lymphocytic leukemia (CLL) to diffuse large-cell lymphoma (DLCL) is commonly referred to as Richter's syndrome. Richter's syndrome occurs mostly in lymph nodes and may represent a second neoplasm or a transformation from the same clonal population. Clinical features in six patients with digestive Richter's syndrome were recorded. Paired samples of CLL and DLCL were investigated by immunohistological analysis (n = 6) and by polymerase chain reaction (PCR) for immunoglobulin heavy-chain gene rearrangement (n = 4). Histological examination revealed the involvement of the gastrointestinal tract by DLCL of B-cell phenotype (n = 6). The same monoclonal rearrangement between CLL and DLCL was demonstrated by PCR and sequencing analyses in two patients. The monoclonal rearrangement was different between CLL and DLCL in only one case. Median survival was 22 months for five patients receiving chemotherapy, suggesting that digestive Richter's syndrome has a better prognosis than nodal Richter's syndrome. Indeed, appropriate surgical resection combined with chemotherapy led to partial or complete remission in four patients.

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.

Lineage switch from acute myeloid leukemia to acute lymphoblastic leukemia: report of an adult case and review of the literature

Lineage switch from AML to ALL is an extremely rare phenomenon, and we report the case of an adult diagnosed with AML at 46 years of age who relapsed with ALL. At initial diagnosis, blast cell morphology and immunophenotyping were consistent with the diagnosis of M4-AML. Complete remission was achieved, and the patient underwent autologous BMT. At relapse, six months after ABMT, blast cells were different from those seen at initial diagnosis, for morphology (L2-ALL), cytochemistry, and immunophenotyping. The karyotype was normal at both diagnosis and relapse. No evidence of bcr-abl fusion genes was found by RT-PCR. Monoclonal IgH and TCR gamma gene rearrangement were evidenced by PCR analysis at relapse but not on blast cells at AML diagnosis.

Expression of Trk isoforms in brain regions and in the striatum of patients with Alzheimer's disease

The TrkAII tyrosine kinase receptor differs from the TrkAI isoform by an insertion of six amino acids in the extracellular domain. We used RT-PCR to determine their respective distribution in rat and human brain. Only trkAII transcripts were detected in 12 rat brain regions, while both trkAI and trkAII transcripts were detected in the cerebellum and pituitary gland. In human, both trkAI and trkAII transcripts were detected in the frontal, temporal, and occipital cortex and thalamus, while only trkAI transcripts were detected in the hippocampus and cerebellum. In the caudate and putamen, trkAII transcripts were exclusively detected. Thereafter, we studied the expression of TrkA isoforms in the striatum of five patients with Alzheimer's disease (AD), four patients with non-AD dementia, seven patients with Parkinson's disease, and six paired nondemented elderly control individuals. In controls and non-AD patients, a constant expression of trkAII transcripts was detected within all striatum parts. In AD patients, a heterogeneous decrease in trkAII expression was observed in the caudate, putamen, and ventral striatum, resulting either in a drop of trkAII transcript levels or in a weak coamplification of trkAII and trkAI transcripts. The alteration of TrkAII gene expression paralleled those of choline acetyltransferase. Together with previous data, this suggests that the alteration of trk gene expression could contribute to a decrease in NGF binding sites and its protective effects on cholinergic neurons of AD patients.

Identification of novel trkA variants with deletions in leucine-rich motifs of the extracellular domain

The peripheral expression of trkA encoding for NGF receptor was investigated by RNase protection assay. A thymus-specific protected fragment was identified. Using 5' rapid amplification of cDNA ends, three different trkA fragments were characterized. The longer fragment corresponded to the classical trkA L3 transcripts while the two shorter fragments lacked sequences encoding for leucine-rich motifs of the extracellular domain of TrkA, similarly to the trkB L1 and L0 variants. RT-PCR analysis of adult rat tissues showed the expression of trkA L1 transcripts in the thymus, testis, lung and kidney but not in the central nervous system. Their combined expression with trkA L3 transcripts suggests that specific peripheral TrkA oligomers may modulate NGF binding and function in non-neuronal cells.

Variation in the histological pattern of nodal involvement by gamma/delta T-cell lymphoma

AIMS

Gamma-delta (gammadelta) T-cell non-Hodgkin's lymphomas (NHLs) usually present with liver, spleen and marrow infiltration. Lymph node involvement by gammadelta T-cell NHL has been rarely documented so far; its histological pattern needs to be further defined.

METHODS AND RESULTS

Two cases of nodal gammadelta T-cell NHL are reported: case 1, a 44-year-old man, presented with cytomegalovirus retinitis and superficial lymphadenopathies. Histological analysis of an inguinal lymph node showed complete destruction by a diffuse pleomorphic lymphoid proliferation, which was positive for CD2, CD3, CD43, CD45, TIA-1 and granzyme B, and displayed a gammadelta phenotype (deltaTCR1+, Vdelta1+, Vdelta2-, Vdelta3-, betaF1-). Bone marrow was normal. Case 2, a male 24-year-old patient with a history of renal transplantation, presented with hepatosplenomegaly and supraclavicular lymph node enlargement. Lymph node architecture was globally preserved. Peripheral sinuses contained scattered nests of medium-sized irregular lymphoid cells. Bone-marrow was infiltrated. Phenotype showed positivity for CD2, CD3, CD45 and TIA1 and expression of gammadelta TCR (deltaTCR1+, deltaV1+, deltaV2-, deltaV3-, betaF1-). Both patients died a short time after diagnosis.

CONCLUSIONS

These observations suggest that at least two forms of nodal gammadelta T-cell NHL may be encountered: one mimicking classical alphabeta T-cell NHL, with diffuse pleomorphic cell proliferation, and one displaying sinusoidal neoplastic infiltration suggesting a close relationship with hepatosplenic gammadelta T-cell NHL.

[Hepatic MALT lymphoma disclosing a nodal extension]

We report a case of a 50-year-old man with chronic viral hepatitis B presenting with a primary hepatic lymphoma of mucosa-associated lymphoid tissue, revealed clinically by a pedicular nodal mass. The liver biopsy showed an active chronic hepatitis and a dense portal lymphoid infiltrate with centrocyte-like cells inducing typical biliary lympho-epithelial lesions. The lymph-node biopsy revealed a marginal zone lymphoma pattern. A monoclonal rearrangement of the immunoglobulin heavy chain gene was detected in the lymph node by polymerase chain reaction. This case of primary hepatic mucosa-associated lymphoid tissue lymphoma confirms that the liver also contains mucosa-associated lymphoid tissue, in which low grade lymphoma can arise.

Intrasinusoidal bone marrow infiltration revealing intravascular lymphomatosis

Intravascular lymphoma is a rare, often fatal disease characterized by a widespread intravascular proliferation of neoplastic lymphoid cells. Dermatological and bizarre neurological manifestations usually predominate. We report a case of intravascular lymphomatosis with an exceptional clinical presentation showing splenomegaly combined with early bone marrow involvement. The diagnosis was made on bone marrow biopsy examination using both immunohistochemistry and molecular biology analysis. We stress the histopathological features of bone marrow involvement by intravascular lymphoma which allow the prompt recognition of this disease. Early systemic chemotherapy, which represents the only chance of remission in such an aggressive disease, can then be initiated.

Meningeal involvement by a transformed mycosis fungoides following Hodgkin's disease

A 58-year-old man had long-standing lesions of presumed large plaque parapsoriasis. Following treatment for nodal Hodgkin's disease (HD), these became more infiltrated, with a diagnosis of mycosis fungoides (MF). A few months later, nodules appeared on the right leg, which was lymphoedematous after inguinal irradiation for HD. Histopathological examination showed CD3+, CD30-, CD15- large pleomorphic lymphocytes, leading to the diagnosis of transformed MF. The cutaneous lesions were successfully treated with topical nitrogen mustard and interferon alfa-2b then methotrexate, but his general health worsened with depression and malaise, without specific neurological symptoms or extracutaneous spreading of the lymphoma. Cerebral computed tomographic scan revealed a cerebellar subdural collection, arachnoid cyst and quadriventricular hydrocephaly, initially considered to be non-specific. After a few weeks, clinical symptoms of intracranial hypertension appeared, and a cerebrospinal fluid (CSF) examination revealed meningeal involvement by the lymphoma. These cells were CD3-negative and the diagnosis was confirmed by polymerase chain reaction (PCR) study, which revealed an identical clonal rearrangement of the T-cell receptor gamma gene between cutaneous biopsies and the CSF. Repeated intrathecal injections of methotrexate and cranial irradiation were performed and the patient was still alive after 13 months. This case illustrates the possible meningeal involvement of MF that may be preceded by atypical and mild neurological or psychiatric symptoms, which may be dissociated from the evolution of the cutaneous lesions. Moreover, PCR study may be useful for both diagnosis and monitoring.

Differential expression of NGF receptors in human thymic epithelial tumors

NGF receptor (TrkA and p75NGFR) expression was investigated in human thymuses, including normal thymuses, thymic hyperplasias, thymomas and thymic carcinomas. TrkAI but not TrkAII transcripts were demonstrated by RT-PCR. In normal thymuses, immunohistochemistry revealed a restricted TrkA-immunoreactivity to epithelial and interdigitated reticular cells, while only interdigitaded reticular cells were immunoreactive for p75NGFR. Thymocytes were negative for both receptors. A switch from the normal TrkA positive-p75NGFR negative phenotype to a TrkA negative-p75NGFR positive phenotype was found in histologically aggressive epithelial cell tumors, suggesting that NGF and its receptors are potentially involved in thymus stroma organogenesis and proliferation.

Loss of Cdk4 expression causes insulin-deficient diabetes and Cdk4 activation results in beta-islet cell hyperplasia

To ascertain the role of cyclin-dependent kinase 4 (Cdk4) in vivo, we have targeted the mouse Cdk4 locus by homologous recombination to generate two strains of mice, one that lacks Cdk4 expression and one that expresses a Cdk4 molecule with an activating mutation. Embryonic fibroblasts proliferate normally in the absence of Cdk4 but have a delayed S phase on re-entry into the cell cycle. Moreover, mice devoid of Cdk4 are viable, but small in size and infertile. These mice also develop insulin-deficient diabetes due to a reduction in beta-islet pancreatic cells. In contrast, mice expressing a mutant Cdk4 that cannot bind the cell-cycle inhibitor P16INK4a display pancreatic hyperplasia due to abnormal proliferation of beta-islet cells. These results establish Cdk4 as an essential regulator of specific cell types.

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.

[Littoral cell angioma: a rare vascular splenic tumor]

Littoral cell angioma is a rare primitive vascular tumor of the spleen considered as benign. Its clinical presentation is non specific. The diagnostic is based on histological and immunohistological analysis. The lesion is composed of anastomosing vascular channels often featuring papillary projections. They are lined by tumoral cells which exhibit an immunoreactivity for vascular and histiomonocytic markers. We report one case of littoral cell angioma and we discuss the diagnosis and the histogenesis of this tumor.

Primary cardiac lymphoma in an immunocompetent woman

We report a fatal primary cardiac non-Hodgkin's lymphoma in a 62 years old immunocompetent woman presenting with tamponade and complete atrioventricular block. CT-scan, echocardiography and autopsy examination showed a tumor largely infiltrating the heart without extracardiac involvement. A surgical biopsy revealed high grade B-cell non-Hodgkin's lymphoma with a misleading myelomonocytic CD68 (KPI) expression. Polymerase Chain Reaction analysis revealed a clonal rearrangement of the immunoglobulin heavy chain gene and confirmed the B-cell origin of the lymphoma. Our report also emphasizes the role of immunohistochemical and molecular techniques in the diagnosis.

Low prevalence of monoclonal B cells in Helicobacter pylori gastritis patients with duodenal ulcer

We have studied the prevalence of B-cell clonality among a large group of 320 patients with Helicobacter pylori gastritis and duodenal ulcer. These patients underwent endoscopic examination with multiple gastric biopsies at diagnosis and were followed 2 and 12 months after therapy. Histopathologic examination of 809 sets of biopsy specimens showed lymphoid gastritis with lymphoid aggregates or follicles, but without lymphoepithelial lesion, in 302 samples corresponding to initial biopsy specimens (n=130) or to posttreatment biopsy specimens (n=172). DNA extracted from fresh antral specimens allowed the amplification of Helicobacter pylori DNA in all cases before therapy. The arrangement of the immunoglobulin heavy chain gene was studied by polymerase chain reaction (PCR) in the 302 selected lymphoid gastritis samples. Single or dominant bands were seen only in four specimens from three patients (1.3%), whereas a polyclonal pattern was seen in the other 298 samples. The detection threshold of our PCR technique was approximately 3% of clonal B cells diluted in a polyclonal population. This threshold appeared to be a reliable cutoff between polyclonal gastritis and clonal MALT lymphoma. In our experience, Helicobacter pylori lymphoid gastritis appeared mainly as a benign polyclonal condition.

Expression of NGF receptors in normal and pathological human thymus

The expression of NGF receptors was investigated in normal human thymus and in thymic hyperplasias, thymomas and thymic carcinomas. By RT-PCR, we detected TrkAI transcripts encoding for the high-affinity NGF receptor. Western blot analysis showed the presence of both TrkA and p75NGFR proteins. In normal thymuses, epithelial subcapsular and medullar cells were TrkA immunoreactive. Interdigitated medullar cells were stained for both TrkA and p75NGFR. While epithelial cells of normal thymuses or benign thymomas exhibited a TrkA positive-p75NGFR negative phenotype, a switch to a TrkA negative-p75NGFR positive phenotype was observed in malignant epithelial cell tumours and was associated with cell proliferation-associated MIB1 expression. Our results argue for a local role of NGF and its receptors on thymic stromal cells both in normal and neoplastic conditions.

Contribution of histopathologic and molecular analyses to the diagnosis of cutaneous B-cell infiltrates

To evaluate the value of morphologic, immunohistochemical and molecular analyses, we studied 21 skin biopsy specimens from 19 patients with primary cutaneous B-cell infiltrates. Morphologic review by two independent dermatopathologists confirmed the consensus diagnoses of lymphoma (n = 6) or benign lymphoid hyperplasia (n = 6). A discordant diagnosis was made for the other samples (n = 9), which were thereafter considered as unclassified lymphoid infiltrates. Immunohistochemical analysis showed either a monotypic expression of immunoglobulin light chain or a positive staining with anti-bcl-2 antibodies in three and four samples, respectively, of lymphoma. Polymerase chain reaction was used to analyze immunoglobulin heavy chain and T-cell receptor gamma chain gene rearrangement and to amplify t(14;18) and t(11;14) break points. A clonal molecular marker was detected in 12 of 19 patients. Among these 12 patients, a final diagnosis of lymphoma was confirmed in 8 patients, including the 6 with a morphologic diagnosis of lymphoma. Two patients with clonal benign lymphoid hyperplasia and two with clonal unclassified lymphoid infiltrate presented a benign clinical outcome; one patient was lost to follow-up. Alternatively, no clonal molecular marker was found in two of the patients with lymphoma. The morphologic and molecular criteria, therefore, provided complementary and partially overlapping information for the diagnosis of cutaneous B-cell infiltrates. We proposed a practical use for these data.

[Splenic lymphoma with villous lymphocytes: morphologic, immunologic and molecular study. Report of three cases]

Splenic lymphoma with villous lymphocytes (SLVL) is a low grade lymphoproliferation characterized by a massive splenomegaly, an absence of lymphadenopathy and the presence in the peripheral blood of atypical B-lymphocytes with hairy-cell appearance. We have studied the morphological, immunological and molecular characteristics of 3 cases of SLVL. SLVL presented on blood smears characteristic irregularities of the plasma membrane consisting in thin and short villi unevenly distributed. The main phenotype was CD5-, CD11c+, and CD25-, but individual SLVL cases can not be identified by using immunohistochemical criteria alone. Clonal rearrangements of the immunoglobulin heavy chain gene were found in all 3 cases and in one case presented a bcl2-JH rearrangement. SLVL are clonal B-cell lymphoproliferations and can be associated with t(14; 18) translocation.

Detection of t(2;5)(p23;q35) translocation by reverse transcriptase polymerase chain reaction and in situ hybridization in CD30-positive primary cutaneous lymphoma and lymphomatoid papulosis

The t(2;5) generates a chimeric NPM-ALK transcript encoded by the nucleophosmin NPM gene fused to the anaplastic lymphoma kinase gene ALK. Using a reverse transcriptase nested polymerase chain reaction assay we have detected NPM-ALK transcripts within CD30+ primary cutaneous lymphoma and lymphomatoid papulosis (LP). The t(2;5) was identified in 4 out of 9 CD30+ anaplastic lymphomas and in 1 out of 4 CD30+ pleomorphic lymphomas. Moreover, the t(2;5) was detected in 3 out of 10 LPs. All NPM-ALK-positive lymphomas and 1 NPM-ALK-positive LP exhibited a clonal rearrangement of the T cell receptor gamma-chain gene. The t(2;5) was detected in 2 cases of LP without other evidence for a clonal lymphoid population. To identify cells carrying the t(2;5) translocation, we used immunohistochemistry to detect the ALK-encoded p80 protein and in situ hybridization for the specific detection of NPM-ALK transcripts. Both p80 protein and NPM-ALK transcripts were expressed by anaplastic or large CD30+ lymphoma cells with positive NPM-ALK amplification. The presence of t(2;5) in a subset of CD30+ cutaneous lymphoma and LP may indicate a common pathogenesis with a subset of anaplastic nodal lymphoma.

Histiocytic sarcoma that mimics benign histiocytosis

A 28-year-old man presented with a histiocytic sarcoma of a very uncommon origin, as it had developed for several years like a benign cutaneous histiocytosis resembling generalized eruptive histiocytoma before becoming acute, with nodal and massive pulmonary involvement. Despite various chemotherapies, the patient died within 8 months. Skin biopsies showed histiocytic proliferation in the dermis and node biopsies showed histiocytic proliferation with a sinusoidal pattern. Immunohistochemical analysis, performed on paraffin-embedded sections, demonstrated strong labeling of tumoral cells for CD68 and moderate labeling for CD3 and CD4. CD30 labeling was negative. S-100 protein was positive on a Langerhans' cell reactive subpopulation. Electron microscopy confirmed the histiocytic nature of malignant cells and showed cytoplasmic inclusions such as regularly laminated bodies, dense bodies and pleomorphic inclusions. No Birbeck granules were seen. A gene rearrangement study of T-cell receptor gamma and immunoglobulin heavy chain genes showed a germline configuration. Histiocytic sarcoma is an extremely rare true histiocytic malignancy, the existence of which has been recently debated since it has often been mistaken in the past for large cell lymphomas. Such a deceptive onset as benign cutaneous histiocytosis has not been described in the literature to our knowledge.

CD30-positive cutaneous large cell lymphomas. A comparative study of clinicopathologic and molecular features of 16 cases

The authors have analyzed and compared the clinicopathologic and molecular features of 16 cases of large cell cutaneous lymphomas expressing CD30 antigen. Three main clinical groups were defined: (1) a group of localized skin disease (7 cases); (2) a group of multicentric skin disease (5 cases); and (3) a group of concomitant skin and extracutaneous disease. Good prognosis was associated with localized skin disease and no history of lymphoma. Interestingly, a majority of Reed Sternberg-like cells was only observed in this group (5 of 6 cases). The two other groups did not show distinctive evolutive nor morphologic features. Southern blot and/or polymerase chain reaction (PCR) technique showed clonality and a T-cell genotype in respectively 13 of 14 and 12 of 12 analyzed cases. Viral infection of tumoral cells was investigated by PCR, in situ hybridization (ISH) or electron microscopy. Epstein-Barr virus (EBV) sequences were detected by PCR and ISH in tumoral cells of cutaneous lesions in one case of skin lymphoma with extracutaneous spreading. No EBV sequence was detected by ISH in the localized lymphomas, whereas HIV particles were visible in tumoral cells in one of these cases. No human T-cell lymphotropic virus (HTLV) tax sequence was amplified by PCR in any case of our series. Our results confirm that CD30-positive cutaneous large cell lymphomas are different clinical and molecular entities. However, a combined clinical and morphologic analysis may help to identify a subset of CD30 cutaneous lymphomas with favorable prognosis.

Simultaneous development of two different B-cell lymphomas in a patient with acquired immune deficiency syndrome evidenced by molecular analysis

We report a case of a man positive for the human immunodeficiency virus who rapidly died of lymphoma with cerebral, lung, and pericardic involvement. After autopsy, histopathological study of the different tumor sites showed the same morphological feature of immunoblastic lymphoma, with large areas of necrosis. In situ hybridization showed monotypic kappa light chain mRNA within lung lymphoma cells and monotypic lambda light chain mRNA within cerebral lymphoma cells. Polymerase chain reaction analysis showed two different immunoglobulin heavy chain gene rearrangements for lung and cerebral lymphoma. Here the simultaneous association of two malignant lymphomas derived from different B-cell clones indicates that molecular analysis of different tumor sites can distinguish between dissemination of the same lymphoma and simultaneous proliferation of different malignant B-cell clones.

Peripheral T-cell lymphoma in a chronically immunosuppressed renal transplant patient

Non-Hodgkin large cell lymphomas occurs more commonly in organ-transplanted patients than in the general population. They are usually of B-cell origin whereas T-cell lymphomas are rare. We report a new case of peripheral T-cell lymphoma in an immunosuppressed renal transplanted patient. The patient presented a hepatosplenic mass with a widespread extension causing serious pancytopenia. It was classified as a pleomorphic medium and large cell type and corresponded to the "common" alpha beta-TCR type lymphoma. Lymphomatous cells exhibited an incomplete mature T-cell phenotype. T-cell receptor gene clonal rearrangement associated with a germline configuration of the immunoglobulin heavy chain gene confirmed a clonal T-cell genotype. By using both Southern blot analysis and polymerase chain reaction, we failed to demonstrate any association with Epstein-Barr virus or human T-cell lymphotropic virus type I or type II.

Infrequent sites of extramedullary relapse after allogeneic bone marrow transplantation

In the present report, we describe two cases of rare extramedullary relapse (skin, muscle) after allogeneic bone marrow transplantation (BMT). As both patients were male and had received sex mismatched (non T-depleted) BMT, marrow samples were analysed with a Y-chromosome specific probe allowing the sensitive detection of host DNA. The proportion of host DNA remained low in all post BMT samples from these patients, even at the time of extramedullary relapse.