Increased expression of MNK1b, the spliced isoform of MNK1, predicts poor prognosis and is associated with triple-negative breast cancer.

MAP kinase interacting kinases (MNKs) modulate the function of oncogene eukaryotic initiation factor 4E (eIF4E) through phosphorylation, which is necessary for oncogenic transformation. MNK1 gives rise to two mRNAs and thus two MNK1 isoforms, named MNK1a and MNK1b. MNK1b, the splice variant of human MNK1a, is constitutively active and independent of upstream MAP kinases. In this study, we have analyzed the expression of both MNK1 isoforms in 69 breast tumor samples and its association with clinicopathologic/prognostic characteristics of breast cancer. MNK1a and MNK1b expression was significantly increased in tumors relative to the corresponding adjacent normal tissue (p < 0.001). In addition, MNK1b overexpression was found in most of the triple-negative tumors and was associated with a shorter overall and disease-free survival time. Overexpression of MNK1b in MDA-MB-231 cells induced an increase in the expression of the MCL1 antiapoptotic protein and promoted proliferation, invasion and colony formation. In conclusion, a high expression level of MNK1b protein could be used as a marker of poor prognosis in breast cancer patients and it could be a therapeutic target in triple-negative tumors.

Apoptosis-related proteins are potential markers of neonatal hypoxic-ischemic encephalopathy (HIE) injury.

Neonatal hypoxic-ischemic encephalopathy (HIE) causes high mortality and long-term morbidity rates. The magnitude of the neuronal damage depends on the duration and severity of the initial insult combined with the deleterious effects of reperfusion and apoptosis. Currently, a diagnosis of HIE is based largely on the neurological and histological findings. Therefore, the aim of this study was to identify apoptosis-related proteins that might serve as potential markers of HIE injury. As an initial step toward reaching this objective, we analyzed changes in protein levels in an in vitro model of hypoxia using antibody arrays, and we have identified changes in the expression level of two proteins involved in apoptosis, Smac-DIABLO and cathepsin D. We obtained brain sections from eight neonatal HIE patients and performed histological staining, TUNEL assays and Smac-DIABLO and cathepsin D immunolocalization. Our results revealed a high number of TUNEL-positive cells, including neurons, astrocytes and ependymal cells, in the various regions that were analyzed. Interestingly, many of the areas that were positive for TUNEL staining did not appear to be damaged in the histological evaluation. In addition, using immunostaining, we found that Smac-DIABLO and cathepsin D had the same regional distribution pattern. Taken together, these findings indicate that these two proteins could serve as markers to identify injured regions that might not to be detectable using histological observations alone.

Infartos cerebrales multifocales asociados a un linfoma B de células grandes intravascular: presentación de un caso / Progressive multifocal cerebral infarction associated with intravascular large B-cell lymphoma: a case report

El linfoma B de células grandes intravascular es una variante poco frecuente de linfoma B de célula grande incluido en la actual clasificación de la Organización Mundial de la Salud. Este linfoma se caracteriza por la ausencia de marcada linfadenopatía, clínica inespecífica y comportamiento agresivo. El diagnóstico de esta neoplasia es difícil y muchos de los casos publicados han sido diagnosticados en autopsias. Presentamos el caso de una mujer de 82 años cuyos primeros síntomas fueron una clínica de infartos cerebrales multifocales progresivos. La paciente desarrolló un deterioro neurológico progresivo. La resonancia magnética mostró la presencia de múltiples infartos y hemorragias en los hemisferios cerebrales. La tríada diagnóstica en estos linfomas está formada por una encefalopatía subaguda, infartos múltiples y elevación sérica de la lactato deshidrogenasa (LDH). Los principales diagnósticos diferenciales en la clínica incluyen vasculitis cerebrales, encefalopatías sépticas o infecciones del sistema nervioso central. Los diagnósticos diferenciales en anatomía patológica incluyen otros tumores con angiotropismo como linfomas T/NK, granulomatosis linfomatoide, carcinomas indiferenciados o melanomas(AU)

Intravascular large B-cell lymphoma is a rare variant of large B-cell lymphoma, according to the current WHO classification. It has a non-specific clinical presentation and is characterised by absence of marked lymphoadenopathy and aggressive behaviour. Its diagnosis is extremely difficult and many of the reported cases were diagnosed post-mortem. We report the case of an 82-year-old woman who presented with the clinical features of progressive multifocal cerebral infarction. Her neurological condition subsequently deteriorated. A brain MRI showed multistage intraparenchymal infarction and haemorrhage in the cerebral hemispheres. The hallmark in this lymphoma is the triad of a subacute encephalopathy, multiple strokes and elevated serum lactate dehydrogenase (LDH) levels. Clinical differential diagnoses should include cerebral vasculitis, septic encephalopathy or infections of the central nervous system. Differential pathological diagnoses include other angiotropic tumours such as T/NK lymphomas, lymphomatoid granulomatosis, undifferentiated carcinoma or malignant melanoma(AU)

Consideraciones quirúrgicas del bocio amiloide / Surgical considerations about amyloid goiter

La amiloidosis es un síndrome poco frecuente, constituido por un conjunto de trastornos que tienen en común el depósito extracelular de proteínas fibrilares. De ello resultan alteraciones funcionales y estructurales de los órganos afectados, dependientes de la localización e intensidad del depósito.La infiltración amiloide del tiroides puede verse en el 50% de la amiloidosis primaria y hasta en el 80% de la forma secundaria. El bocio amiloide (BA) es una verdadera rareza, habitualmente asociado a la forma secundaria. El BA puede tener indicación quirúrgica, generalmente justificada por problemas compresivosComunicamos el caso de un paciente con un gran BA en el curso de una amiloidosis secundaria asociada a una artritis idiopática juvenil de inicio poliarticular, al que se le practicó una tiroidectomía total. Revisamos la literatura, intentando aportar pautas de actuación y algunas consideraciones quirúrgicas sobre esta rara afección (AU)

Amyloidosis is an uncommon syndrome consisting of a number of disorders having in common an extracellular deposit of fibrillary proteins. This results in functional and structural changes in the affected organs, depending on deposit location and severity.Amyloid infiltration of the thyroid gland may occur in 50% and up to 80% of patients with primary and secondary amyloidosis respectively. Amyloid goiter (AG) is a true rarity, usually found associated to secondary amyloidosis. AG may require surgical excision, usually because of compressive symptoms.We report the case of a patient with a big AG occurring in the course of a secondary amyloidosis associated to polyarticular onset juvenile idiopathic arthritis who underwent total thyroidectomy. Current literature is reviewed, an attempt is made to provide action guidelines, and some surgical considerations on this rare condition are given (AU)

Surgical considerations about amyloid goiter.

Amyloidosis is an uncommon syndrome consisting of a number of disorders having in common an extracellular deposit of fibrillary proteins. This results in functional and structural changes in the affected organs, depending on deposit location and severity. Amyloid infiltration of the thyroid gland may occur in 50% and up to 80% of patients with primary and secondary amyloidosis respectively. Amyloid goiter (AG) is a true rarity, usually found associated to secondary amyloidosis. AG may require surgical excision, usually because of compressive symptoms. We report the case of a patient with a big AG occurring in the course of a secondary amyloidosis associated to polyarticular onset juvenile idiopathic arthritis who underwent total thyroidectomy. Current literature is reviewed, an attempt is made to provide action guidelines, and some surgical considerations on this rare condition are given.

Axonal and oligodendrocyte-localized IgM and IgG deposits in MS lesions.

BACKGROUND: Recent findings support the important role of antibodies in multiple sclerosis (MS) physiopathology. Thus, local IgG synthesis is a hallmark of the disease, and intrathecal IgM synthesis associates with a poor disease outcome. METHODOLOGY: The aim of this study was to investigate the presence of IgM and IgG in demyelinating lesions using high sensitivity immunohistochemistry techniques in necropsies from fourteen MS patients, four controls without neurological disease and four cases with non MS CNS inflammatory disease. RESULTS: IgG and IgM were absent in controls. Conversely, we found IgM in about 50% and IgG in 75% of MS patients. The presence of IgM and IgG antibodies was independent of disease duration, clinical disease type or lesion stage. IgM and IgG were present in acute, chronic active and chronic inactive lesions. Double immunofluorescence showed that IgM and IgG were detected on axons and oligodendrocytes in demyelinated areas. Moreover, we observed immunoglobulin deposits on oligodendrocytes in NAWM in some cases. IgG and IgM colocalized with complement C3b on demyelinated axons and oligodendrocytes and antibody-antigen immunocomplexes were detected in foamy macrophages in active lesion areas. These findings were absent from cases of non-neurological disease and cases with non-MS CNS inflammatory disease. SIGNIFICANCE OF THE STUDY: These observations provide further evidence on the role of antibodies, complement and macrophages in plaque development, and strongly suggest they can induce axonal injury, an important cause of disability in MS. They may provide novel therapeutic strategies to limit tissue degeneration in the disease.

Autosomal recessive Emery-Dreifuss muscular dystrophy caused by a novel mutation (R225Q) in the lamin A/C gene identified by exome sequencing.

INTRODUCTION: The aim of this study is to describe a new mutation in the LMNA gene diagnosed by whole exome sequencing. METHODS: A two-generation kindred with recessive limb-girdle muscular dystrophy was evaluated by exome sequencing of the proband's DNA. RESULTS: Exome sequencing disclosed 194,618 variants (170,196 SNPs, 8482 MNPs, 7466 insertions, 8307 deletions, and 167 mixed combinations); 71,328 were homozygotic and 123,290 were heterozygotic, with 11,753 non-synonymous, stop-gain, stop-loss, or frameshift mutations occurring in the coding region or nearby intronic region. The cross-referencing of these mutations in candidate genes for muscular dystrophy showed a homozygote mutation c.G674A in exon 4 of LMNA causing a protein change R225Q in an arginine conserved from human to Xenopus tropicalis and in lamin B1. CONCLUSIONS: This technique will be preferred for studying patients with muscular dystrophy in the coming years.

An off-target nucleostemin RNAi inhibits growth in human glioblastoma-derived cancer stem cells.

Glioblastomas (GBM) may contain a variable proportion of active cancer stem cells (CSCs) capable of self-renewal, of aggregating into CD133(+) neurospheres, and to develop intracranial tumors that phenocopy the original ones. We hypothesized that nucleostemin may contribute to cancer stem cell biology as these cells share characteristics with normal stem cells. Here we report that nucleostemin is expressed in GBM-CSCs isolated from patient samples, and that its expression, conversely to what it has been described for ordinary stem cells, does not disappear when cells are differentiated. The significance of nucleostemin expression in CSCs was addressed by targeting the corresponding mRNA using lentivirally transduced short hairpin RNA (shRNA). In doing so, we found an off-target nucleostemin RNAi (shRNA22) that abolishes proliferation and induces apoptosis in GBM-CSCs. Furthermore, in the presence of shRNA22, GBM-CSCs failed to form neurospheres in vitro or grow on soft agar. When these cells are xenotransplanted into the brains of nude rats, tumor development is significantly delayed. Attempts were made to identify the primary target/s of shRNA22, suggesting a transcription factor involved in one of the MAP-kinases signaling-pathways or multiple targets. The use of this shRNA may contribute to develop new therapeutic approaches for this incurable type of brain tumor.

Eukaryotic initiation factors (eIF) 2alpha and 4E expression, localization, and phosphorylation in brain tumors.

Increased protein synthesis is regulated, in part, by two eukaryotic translation initiation factors (eIFs): eIF4E and eIF2alpha. One or both of these factors are often overexpressed in several types of cancer cells; however, no data are available at present regarding eIF4E and eIF2alpha levels in brain tumors. In this study, we analyzed the expression, subcellular localization and phosphorylation states of eIF4E and eIF2alpha in 64 brain tumors (26 meningiomas, 16 oligodendroglial tumors, and 22 astrocytomas) and investigated the correlation with the expression of MIB-1, p53, and cyclin D1 proteins as well. There are significant differences in the phosphorylated eIF4E levels between the tumors studied, being the highest in meningiomas and the lowest in the oligodendroglial tumors. Relative to subcellular localization, eIF4E is frequently found in the nucleus of the oligodendroglial tumors and rarely in the same compartment of the meningiomas, whereas eIF2alpha showed an inverse pattern. Finally, cyclin D1 levels directly correlate with the phosphorylation status of both factors. The different expression, phosphorylation, or/and subcellular distribution of eIF2alpha and eIF4E within the brain types of tumors studied could indicate that different pathways are activated for promoting cell cycle proliferation, for instance, leading to increased cyclin D1 expression.

A new antigen retrieval technique for human brain tissue.

Immunohistochemical staining of tissues is a powerful tool used to delineate the presence or absence of an antigen. During the last 30 years, antigen visualization in human brain tissue has been significantly limited by the masking effect of fixatives. In the present study, we have used a new method for antigen retrieval in formalin-fixed human brain tissue and examined the effectiveness of this protocol to reveal masked antigens in tissues with both short and long formalin fixation times. This new method, which is based on the use of citraconic acid, has not been previously utilized in brain tissue although it has been employed in various other tissues such as tonsil, ovary, skin, lymph node, stomach, breast, colon, lung and thymus. Thus, we reported here a novel method to carry out immunohistochemical studies in free-floating human brain sections. Since fixation of brain tissue specimens in formaldehyde is a commonly method used in brain banks, this new antigen retrieval method could facilitate immunohistochemical studies of brains with prolonged formalin fixation times.

Psammomatoid ossifying fibromas: immunohistochemical analysis and differential diagnosis with psammomatous meningiomas of craniofacial bones.

OBJECTIVE: To clarify the role of immunohistochemistry in the diagnosis of psammomatoid ossifying fibroma (PSOF), conventional cemento-ossifying fibroma (COF), and psammomatous meningioma (PM) of the craniofacial skeleton. STUDY DESIGN: The histology and immunohistochemistry of 4 PSOFs, 6 COFs, and 7 PMs was studied. Antibodies included EMA, cytokeratins, smooth muscle actin (SMA), desmin, vimentin, CD34, CD10, S-100 protein, and glial fibrillary acidic protein (GFAP). RESULTS: All PSOFs showed multiple round ossicles homogeneously distributed within a fibroblastic stroma. Psammomatous meningiomas had meningothelial features. All tumors, except 1 COF, were positive for EMA. All of them expressed vimentin, and none showed cytokeratins. Staining for SMA and S-100 protein was variable. CD10 was positive in all cases except 2 meningiomas. CD34 and GFAP stained only 1 case of meningioma each. CONCLUSIONS: The diagnosis of PSOF should rest on histologic features. An incorrect diagnosis of meningioma based on the expression of EMA should be avoided.

Type 2 diabetes mellitus, its treatment and risk for lymphoma.

In this study, we have investigated a potential association between Type 2 diabetes mellitus and its treatment with the risk of lymphoma. Here, we report on 565 incident lymphoma (non-Hodgkin and Hodgkin), multiple myeloma, and chronic lymphocytic leukemia cases and 601 hospital controls in a Spanish multicentric case-control study. Information on diabetes mellitus diagnosis and treatment was obtained through personal interview together with information on other known or putative risk factors for lymphoma. The average age of the study population was 59 years. A medical diagnosis of diabetes was reported by 11% of the controls and 16.3% of cases. Patients with diabetes mellitus not treated with drugs were at an increased risk for lymphoma (OR=1.73, 95%CI=1.11, 2.68), and particularly for multiple myeloma (OR=2.80, 95%CI=1.40, 5.59). Patients treated with insulin had a non-significantly reduced risk for lymphoma (OR=0.70, 95%CI=0.29, 1.67). If replicated, this effect could be explained by a disappearance of hyperinsulinaemia in patients requiring insulin or to the continuous stimulation of the immune system by insulin.

Occupational exposure to immunologically active agents and risk for lymphoma.

OBJECTIVES: We evaluated whether occupational exposure to high molecular weight agents that are associated with asthma and that act predominantly through an immunoglobulin E (IgE)-dependent hypersensitivity mechanism is also associated with risk for specific lymphoma types. METHODS: The Spanish lymphoma case-control study includes 519 newly diagnosed cases of lymphoid neoplasms and 554 hospital controls ages 20 to 80 years. Lymphomas were histologically or cytologically confirmed and classified according to the WHO classification. Lifetime occupational exposure to seven high molecular weight agents such as latex was evaluated through an asthma-specific job-exposure matrix and validated by an industrial hygienist. Odds ratios (OR) and 95% confidence intervals (95% CI) were adjusted for age, sex, hospital, and occupational exposures. RESULTS: Subjects exposed to high molecular weight agents had an increased risk for Hodgkin's lymphoma (OR, 2.27; 95% CI, 0.93-5.50), particularly nodular sclerosis (OR, 3.22; 95% CI, 1.14-9.09). ORs did not increase with duration of exposure to these agents. Exposure to high molecular weight agents was not associated with risk of other B-cell lymphomas; for most specific subcategories of B-cell lymphoma, ORs were below unity. A slightly increased OR (95% CI) was seen for mycosis fungoides [1.60 (0.53-4.84)], although overall there was no increased risk for T-cell lymphomas. CONCLUSIONS: Exposure to immunologically active agents among clinically immunocompetent subjects was associated with risk for Hodgkin's lymphoma.

CpG island hypermethylation of the DNA repair enzyme methyltransferase predicts response to temozolomide in primary gliomas.

PURPOSE: The DNA repair enzyme O(6)-methylguanine DNA methyltransferase (MGMT) inhibits the killing of tumor cells by alkylating agents, and its loss in cancer cells is associated with hypermethylation of the MGMT CpG island. Thus, methylation of MGMT has been correlated with the clinical response to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in primary gliomas. Here, we investigate whether the presence of MGMT methylation in gliomas is also a good predictor of response to another emergent alkylating agent, temozolomide. EXPERIMENTAL DESIGN: Using a methylation-specific PCR approach, we assessed the methylation status of the CpG island of MGMT in 92 glioma patients who received temozolomide as first-line chemotherapy or as treatment for relapses. RESULTS: Methylation of the MGMT promoter positively correlated with the clinical response in the glioma patients receiving temozolomide as first-line chemotherapy (n = 40). Eight of 12 patients with MGMT-methylated tumors (66.7%) had a partial or complete response, compared with 7 of 28 patients with unmethylated tumors (25.0%; P = 0.030). We also found a positive association between MGMT methylation and clinical response in those patients receiving BCNU (n = 35, P = 0.041) or procarbazine/1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (n = 17, P = 0.043) as first-line chemotherapy. Overall, if we analyze the clinical response of all of the first-line chemotherapy treatments with temozolomide, BCNU, and procarbazine/1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea as a group in relation to the MGMT methylation status, MGMT hypermethylation was strongly associated with the presence of partial or complete clinical response (P < 0.001). Finally, the MGMT methylation status determined in the initial glioma tumor did not correlate with the clinical response to temozolomide when this drug was administered as treatment for relapses (P = 0.729). CONCLUSIONS: MGMT methylation predicts the clinical response of primary gliomas to first-line chemotherapy with the alkylating agent temozolomide. These results may open up possibilities for more customized treatments of human brain tumors.

Focal monophasic demyelinating leukoencephalopathy in advanced HIV infection.

A multiple sclerosis (MS)-like illness has been reported in human immunodeficiency virus (HIV)-infected patients, usually in the early stages of HIV infection. We report 3 patients with advanced HIV infection (CD4 lymphocyte count under 200/mm(3)) presenting with monophasic focal leukoencephalopathy, in whom biopsy demonstrated demyelinating lesions compatible with acute MS lesions. In 1 patient, recently started on highly active antiretroviral therapy, MS-like disease could represent an immune reconstitution syndrome. The lesions were reversible in 2 patients, but rapidly fatal in the third patient. These cases show that an MS-like disease may present in advanced HIV infection as focal monophasic leukoencephalopathy with either a reversible or fulminating course, mimicking progressive multifocal leukoencephalopathy.

Helicobacter pylori and malignant lymphoma in Spain.

UNLABELLED: Helicobacter pylori has been associated with gastric adenocarcinoma and gastric lymphoma. We report on the systematic evaluation of serologic detection of H. pylori in a lymphoma case-control study. METHODS: Cases (N = 536) were consecutive patients newly diagnosed with a lymphoid malignancy between 1998 and 2002 in four centers in Spain. Lymphomas were diagnosed and classified using the WHO Classification. Controls (N = 603) were hospitalized patients frequency-matched to the cases by 5-year age group, sex, and study center. Severe immunocompromised patients were excluded as controls. Patients underwent a personal interview and blood sampling. H. pylori infection was evaluated by the presence of IgG antibodies using the Premier enzyme immunoassay kit (Meridian Diagnostics Inc., Cincinnati, OH). Logistic regression analysis was used to estimate the odds ratios and 95% confidence intervals (OR, 95% CI) for lymphoma categories. RESULTS: Anti-H. pylori antibodies were detected in 68.5% of the cases and 71.3% of the controls (P = 0.29) H. pylori was associated with a 3-fold excess risk of splenic marginal B-cell lymphoma (OR = 3.97, 95% CI = 0.92-17.16). H. pylori was not associated with an overall increased risk of extranodal lymphomas (OR = 0.73, 95% CI = 0.44-1.22) but when specific sites were explored, the four mucosa-associated lymphoid tissue and the six diffuse large B-cell lymphomas primary localized in the stomach were all H. pylori seropositive. CONCLUSION: Persistent infection with H. pylori may be implicated in the development of lymphomas of the gastric mucosa and of the spleen. These results could have clinical implications in the management of splenic marginal zone lymphomas.

Lack of serological evidence for an association between simian virus 40 and lymphoma.

Recent studies have implicated simian virus 40 (SV40) in non-Hodgkin's lymphomas based on detection of SV40 DNA sequences. We employed a virus-like-particle (VLP)-based enzyme immunoassay for antibodies to SV40 to test sera from 520 lymphoma cases and 587 controls in Spain. The SV40 seroprevalence was 9.5% in controls and 5.9% in cases. Antibody levels of the positive sera were low. There was no association of SV40 seropositivity with any subtype of lymphoma. VLPs of the human BK virus substantially inhibited the SV40 reactivity of human sera. There was no serological evidence of widespread SV40 infection and no association of SV40 seropositivity with human lymphomas in Spain.

Análisis de clonalidad en el linfoma cerebral primario mediante PCR / No disponible

Introducción: Establecer la diferencia entre poblaciones linfocitarias monoclonales y reactivas puede ser de gran ayuda en el diagnóstico del linfoma cerebral primario (LCP), especialmente en pequeñas muestras obtenidas por biopsia estereotáxica. El objetivo de este estudio ha sido evaluar la frecuencia de reordenamientos clonales del gen de la cadena pesada de las inmunoglobulinas (IgH) en el LCP. Métodos: Se han estudiado 24 LCP, 16 en pacientes inmunocompetentes y 8 asociados a SIDA. Mediante el método de reacción en cadena de la polimerasa (PCR) se analizó el gen IgH utilizando ADN extraído de tejido fijado en formol e incluido en parafina. Para ello se amplificaron las regiones CDR II y CDR III de dicho gen mediante cebadores consenso para las regiones VH (Fr2 y Fr3, respectivamente) y JH (LJH y VLJH). Resultados: El análisis molecular confirmó la existencia de clones de células B en un importante numero de casos de LCP. Al usar ambas combinaciones de cebadores (Fr2 y Fr3) se detectaron reordenamientos clonales del gen IgH en 19 de los 24 casos (79%), observándose en 5 de éstos un patrón biclonal debido a la presencia de dos bandas discretas con Fr3. La frecuencia de detección de clonalidad fue similar en los dos grupos de pacientes. Conclusiones: Nuestras observaciones apoyan que el estudio de la clonalidad del gen IgH mediante PCR en biopsias incluidas en parafina es de utilidad en el diagnóstico del LCP (AU)

Introduction: To determine differences between monoclonal and reactive lymphoid populations may be a great help in the diagnosis of primary brain lymphoma (PBL). The aim of this study was to evaluate the frequency of clonal immunoglobulin heavy chain (IgH) gene rearrangements in PBL. Methods: Twenty-four PBL were studied, 16 of them from immunocompetent patients and another 8 from AIDS patients. DNA was extracted from formalin-fixed, paraffin- embedded tissue. IgH gene rearrangements were analyzed using the polymerase chain reaction method (PCR) by amplifying CDRII and CDRIII regions using consensus primers directed to framework regions VH (Fr2 and Fr3 respectively) and JH (LJH and VLJH). Results: Molecular analysis confirmed the existence of B-cell clones in an important number of cases of PBL. Using both primer combinations (Fr2 and Fr3) we detected clonal IgH gene rearrangements in 19 of the 24 cases (79%), and 5 of these cases showed a biclonal pattern due to the presence of two discrete bands with Fr3. The frequency of detection of clonality was similar in both groups of patients. Conclusions: Our data confirm that PCR analysis of IgH rearrangements in paraffin-embedded biopsies is useful in the diagnosis of PBL (AU)