Profiling of Copy Number Alterations Using Low-Coverage Whole-Genome Sequencing Informs Differential Diagnosis and Prognosis in Primary Cutaneous Follicle Center Lymphoma.

Primary cutaneous follicle center lymphoma (PCFCL) has an excellent prognosis using local treatment, whereas nodal follicular lymphoma (nFL), occasionally presenting with cutaneous spread, often requires systemic therapy. Distinction of the 2 diseases based on histopathology alone might be challenging. Copy number alterations (CNAs) have scarcely been explored on a genome-wide scale in PCFCL; however, they might serve as potential biomarkers during differential diagnosis and risk stratification. Low-coverage whole-genome sequencing is a robust, high-throughput method for genome-wide copy number profiling. In this study, we analyzed 28 PCFCL samples from 20 patients and compared the copy number profiles with a cohort of diagnostic samples of 64 nFL patients. Although the copy number profile of PCFCL was similar to that of nFL, PCFCL lacked amplifications of 18q, with the frequency peaking at 18q21.33 in nFL cases involving the BCL2 locus (PCFCL: 5.0% vs nFL: 31.3%, P = .018, Fisher exact test). Development of distant cutaneous spread was significantly associated with higher genomic instability including the proportion of genome altered (0.02 vs 0.13, P = .033) and number of CNAs (2 vs 9 P = .017), as well as the enrichment of 2p22.2-p15 amplification involving REL and XPO1 (6.3% vs 60.0%, P = .005), 3q23-q24 amplification (0.0% vs 50.0%, P = .004), 6q16.1-q23.3 deletion (6.3% vs 50.0%, P = .018), and 9p21.3 deletion covering CDKN2A and CDKN2B loci (0.0% vs 40.0%, P = .014, all Fisher exact test) in PCFCL. Analysis of sequential tumor samples in 2 cases harboring an unfavorable clinical course pointed to the acquisition of 2p amplification in the earliest common progenitor underlining its pivotal role in malignant transformation. By performing genome-wide copy number profiling on the largest patient cohort to date, we identified distinctive CNA alterations conceivably facilitating the differential diagnosis of PCFCL and secondary cutaneous involvement of nFL and potentially aiding the risk stratification of patients with PCFCL in the future.

Histopathological aspects and differential diagnosis of CD8 positive lymphomatoid papulosis.

Lymphomatoid papulosis (LyP) belongs to CD30+ lymphoproliferative disorders with indolent clinical course. Classic histological subtypes, A, B and C are characterized by the CD4+ phenotype, while CD8+ variants, most commonly classified as type D, were reported in recent years. We present 14 cases of CD8+ LyP. In all patients, self-resolving or treatment-sensitive papules were observed. Of 14 cases 7 produced results with typical microscopic features of LyP type D mimicking primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma. The infiltration pattern in 4 of 14 cases were consistent with classic LyP type B, without CD30 expression in two cases, resembling mycosis fungoides (MF). The morphology of 2 of 14 cases shared a certain consistency with classic type A and C, lacking eosinophils and neutrophils. Extensive folliculotropism characteristic to type F was observed in 1 of 14 case. Significant MUM1 and PD1 expression were detected in 2 of 14 and 3 of 14 cases, respectively. We concluded that CD8+ LyP may present with different histopathological features compared with type D, similar to CD4+ LyP variants. Differential diagnoses include CD8+ papular MF, folliculotropic MF and anaplastic large cell lymphoma in addition to primary cutaneous aggressive epidermotropic T-cell lymphoma. We emphasise that rare CD8+ LyP cases may exist with CD30-negativity.

[Molecular and histological features of diffuse large B-cell lymphoma]. / A diffúz nagy B-sejtes limfóma genetikai és patológiai sajátosságai.

Diffuse large B-cell lymphoma (DLBCL) is a high-grade lymphoproliferative disease of mature B cells, representing the most common lymphoid malignancy of adulthood. There are multiple distinct subgroups of DLBCL in the 2008 WHO classification, organ specific forms, DLBCL associated with immunodeficiency and viral infections and rare CD20 negative and intermediate forms. However, most of the cases are still classified under the DLBCL not otherwise specified (NOS) category. This group of disease shows remarkable heterogeneity with respect to clinical presentation, biology and response to treatment, reflecting several molecular subgroups: the origin of B cells at various developmental stages, the oncogenic pathways that drive tumor development and also epigenetic changes and mutations involving the escape of immune surveillance. Contemporary chemo-immunotherapy does not result in durable remissions in as many as 30% of the cases. To achieve longer survival, the definition of new biomarkers are needed for targeted therapy based on better subgrouping of tumors according to the molecular pathways involved in lymphomagenesis. This paper summarizes the most important features influencing the outcome of this broad disease at the level of morphology, phenotype and genotype and gives a guideline for the routine pathological practice at present for the diagnostics of DLBCL treated by chemo-immunotherapy.

[Characteristics of the course of lupus erythematosus panniculitis in a retrospective analysis of 17 patients]. / A lupus erythematosus panniculitis lefolyásának jellegzetességei 17 betegünk retrospektív vizsgálata alapján.

INTRODUCTION: Lupus erythematous panniculitis (LEP) is a rare type of chronic cutaneous lupus erythematous. Clinical characteristics are tender, subcutaneous nodules, erythematous plaques. Disfigurement of face and body might develop which affects the patient's quality of life. LEP can be the first sign of systemic lupus erythematous (SLE). OBJECTIVE: Our aim was to review the clinicopathological characteristics and the course of LEP through our own patients. METHODS: We retrospectively analyzed the clinical records of 17 LEP patients at Semmelweis University's Department of Dermatology, Venerology and Dermatooncology between 2000 and 2022. RESULTS: The male : female ratio was 1 : 16, average age was 37.8 years. Lesion localisations were proximal lower (8/17) and upper extremities (7/17), face (4/17), breast (3/17), chest (2/17), buttocks (2/17), back (1/17) and distal lower extremity (1/17). Lesion morphologies were nodules (11/17), plaques (7/17), lipoatrophy (4/17), ulceration (3/17), calcification (1/17). Discoid changes covered in 6 cases. In 10 cases, systemic symptoms were observed (arthritis (4/17), haematological (5/17), renal (2/17), anti-phospholipid syndrome (2/17). 7 patients fulfilled the EULAR/ACR criteria for SLE. Histology showed mixed type panniculitis in 8, lobular in 3 cases. Average time until diagnosis was 24.3 months. Among all our SLE patients, skin symptoms regressed following systemic immunosuppressive treatment. LEP patients with only skin manifestation were often resistant for the therapy of cutaneous lupus erythematous. CONCLUSION: The diagnosis of LEP often takes months or years. Wider knowledge of LEP would shorten the time to diagnosis, preventing disfigurement and possible damage of internal organs. Based on our observations, LEP without SLE might be treated with early immunosuppression. Orv Hetil. 2023; 164(5): 172-178.

Scrofuloderma and granuloma annulare-like lesions: Challenges of diagnosing cutaneous tuberculosis in developed countries.

Tuberculosis remains a global health concern, as the increasing levels of urban poverty, higher number of immunodeficient patients and the development of drug resistance threaten the overall efforts made to induce a downward trend for the disease. Scrofuloderma, also known as tuberculosis cutis colliquativa is a subtype of cutaneous tuberculosis. Here we detail a case of a 70-year-old female patient presented with unilateral, left-sided, multiple palpable, painful, ulcerated and purulent cervical nodules, accompanied by persistent generalized erythematous popular granuloma annulare-like skin lesions on the upper extremities. Based on the result of the PCR assay, culture, imaging and histopathological findings, the diagnosis of scrofuloderma was established. To achieve prompt diagnosis and early treatment, it is crucial to include scrofuloderma in the differential diagnosis of ulcerated lesions in developed countries as well, and also be aware of the additional clinical symptoms, such as granuloma annulare-like lesions, possibly accompanying cutaneous tuberculosis.

Potential role of MAP2K1 mutation in the trans-differentiation of interdigitating dendritic cell sarcoma: Case report and literature review.

A 5-year-old male child was diagnosed with interdigitating dendritic cell sarcoma (IDCS) during his maintenance therapy for B-cell precursor acute lymphoblastic leukemia (B-ALL). Multiplex lymph node involvements of the neck were found by positron emission tomography CT (PET-CT). Treatments, including surgical and chemotherapy, resulted in complete remission. Four years later, systemic bone infiltration was discovered. Surgical resection of the IV rib and intensive chemotherapy led to a complete morphological remission, and allogeneic bone marrow transplantation was performed. Comprehensive genomic profiling of the formalin fixed the tumor tissue, and the cryopreserved leukemic cells revealed several common alterations and divergent clonal evolution with a novel MAP2K1 mutation of the IDCS, which is responsible for the trans-differentiation of the common lymphoid-committed tumor progenitor.

Immunohistochemical Study of the PD-1/PD-L1 Pathway in Cutaneous Lupus Erythematosus.

The pathomechanism of various autoimmune diseases is known to be associated with the altered function of programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) axis. We aimed to investigate the role of this pathway and inflammatory cell markers in subtypes of cutaneous lupus erythematosus (CLE): discoid lupus erythematosus (DLE), subacute CLE (SCLE) and toxic epidermal necrolysis (TEN)-like lupus, a hyperacute form of acute CLE (ACLE). Ten skin biopsy samples from 9 patients were analyzed with immunohistochemistry regarding the following markers: CD3, CD4, CD8, Granzyme B, CD123, CD163, PD-1, PD-L1. Our group consisted of 4 SCLE (2 idiopathic (I-SCLE) and 2 PD-1 inhibitor-induced (DI-SCLE)), 4 DLE and 1 TEN-like lupus cases. From the latter patient two consecutive biopsies were obtained 1 week apart. Marker expression patterns were compared through descriptive analysis. Higher median keratinocyte (KC) PD-L1 expression was observed in the SCLE group compared to the DLE group (65% and 5%, respectively). Medians of dermal CD4, Granzyme B (GB), PD-1 positive cell numbers and GB+/CD8+ ratio were higher in the DLE group than in the SCLE group. The I-SCLE and DI-SCLE cases showed many similarities, however KC PD-L1 expression and dermal GB positive cell number was higher in the former. The consecutive samples of the TEN-like lupus patient showed an increase by time within the number of infiltrating GB+ cytotoxic T-cells and KC PD-L1 expression (from 22 to 43 and 30%-70%, respectively). Alterations of the PD-1/PD-L1 axis seems to play a role in the pathogenesis of CLE.

Central nervous system involvement in CD4+/CD56+ hematodermic neoplasm: a report of two cases.

CD4+/CD56+ hematodermic neoplasm, formerly known as blastic NK-cell lymphoma, is an uncommon, aggressive non-Hodgkin's lymphoma with cutaneous, lymph node, and bone marrow involvement at presentation. The disease is characterized by early leukemic phase; however, central nervous system involvement is rarely reported. Herein we describe two cases of CD4+/CD56+ hematodermic neoplasm with meningeal manifestation. Microscopic analysis and flow cytometry of cerebrospinal fluid proved to be diagnostic; however, imaging studies were not informative. These observations call attention to the possibility of central nervous system involvement, which could be more common than expected previously. Authors recommend routine cerebrospinal fluid analysis and prophylactic intrathecal chemotherapy in patients with this highly aggressive disease.

The Effect of CD86 Expression on the Proliferation and the Survival of CLL Cells.

Micro-environment plays important role in the pathogenesis of CLL by providing protective niche for CLL cells. Several molecules play important role in communication between CLL cells and immune cells like CD86.Some of the data suggest that CLL patients with high CD86 level need earlier treatments and cells with higher CD86 expression has higher proliferation rate but the role of CD86 in the survival and proliferation of CLL cells is unclear. We investigated the effect of CD86 expression to CLL cells in 50 peripheral blood and 15 lymph node biopsy samples from CLL patients. Our results showed that the expressions of CD86 increased significantly after 7 day culturing in medium, or in the presence of bone marrow stromal cells (BMSCs). We found positive correlation between CD86 and CD23 expression (p < 0.05), but no correlation with other markers. Furthermore, no correlation were found between the CD86 expression and the proliferation of CLL cells. Analysis of clinical data showed that cases with high CD86 expression had lower level of serum lymphocyte count (p < 0.04) at the time of the diagnosis. CD86 shows multiple appearances in the lymph nodes containing pseudofollicules, but no correlation was found between CD86 positivity, and Ki67 positivity. Our results suggest that the use of CD86 molecule as a proliferation marker for CLL is highly questionable. However, the CD86 molecule may interfere with the immune system of patients with CLL by activating and depleting immune functions. That can be the reason why CD86 positivity may mean worse prognosis.

Somatic hypermutation of IGVH genes and aberrant somatic hypermutation in follicular lymphoma without BCL-2 gene rearrangement and expression.

BACKGROUND: Follicular lymphoma is characterized by the t(14;18) translocation resulting in constitutive expression of BCL-2 protein; however approximately 10-15% of follicular lymphomas do not express BCL-2 protein, and a small fraction of these cases does not exhibit translocation of the BCL-2 gene either. It is highly debated whether cases of follicular lymphoma without BCL-2 gene rearrangement and expression represent a separate lymphoma entity with distinct biological characteristics, different from the BCL-2-positive cases. DESIGN AND METHODS: To further characterize follicular lymphomas without BCL-2 gene rearrangement and expression, we analyzed and compared the mutational status of IGVH genes as well as other genes (C-MYC, PAX-5 and RHOH) frequently involved in the specific type of genomic instability called aberrant somatic hypermutation in 11 cases of BCL-2-negative and 7 cases of BCL-2-positive follicular lymphomas. We also determined the levels of expression of activation-induced cytidine deaminase in these cases. RESULTS: The analyzed cases were grade 2 and grade 3A follicular lymphomas. Our findings demonstrate that follicular lymphomas without BCL-2 gene rearrangement and expression are associated with ongoing somatic hypermutation of the IGVH genes, low activity of aberrant somatic hypermutation and elevated activation-induced cytidine deaminase expression. These results were in concordance with the results found in the cases of BCL-2-positive follicular lymphoma. CONCLUSIONS: Although, BCL-2 protein overexpression is considered to be a critical pathogenic event in the development of follicular lymphoma, our findings suggest that follicular lymphomas with the same morphology, immunophenotype, mutational pattern and activation-induced cytidine deaminase expression may develop without the involvement of BCL-2 gene. The present data support the hypothesis that BCL-2-positive and BCL-2-negative follicular lymphomas (grades 1-3A) represent a homogenous group with different initial but several common additional molecular pathways.

Concomitant 1p36 deletion and TNFRSF14 mutations in primary cutaneous follicle center lymphoma frequently expressing high levels of EZH2 protein.

Primary cutaneous follicle center lymphoma (PCFCL) is an indolent variant of follicular lymphoma (FL) with limited information available on the genetic background of the disease. The genetic hallmark of nodal FL, the t(14;18) translocation, affecting the BCL2 gene, is rare in PCFCL. Loss of 1p36, the most common secondary chromosomal abnormality in nodal FL, has been recently reported in 16.7% of PCFCL cases. In order to further characterize PCFCL, 21 cases were analyzed using interphase fluorescence in situ hybridization with BCL2 break apart and 1p36/1q25 dual color probes. Sanger sequencing was used to investigate TNFRSF14 and EZH2 mutations and immunohistochemistry to assess BCL2, EZH2 protein expressions.1p36 deletion occurred in 22% (5/21), BCL2 gene break in 10% (2/20) of the PCFCL cases. Mutations of the candidate tumor suppressor gene of the 1p36 region, TNFRSF14 mutations were detected in 4/17 (23.5%) cases with 2 cases presenting with concurrent 1p36 deletion. EZH2 hotspot mutations at Y641, A682, and A692 were not found. High EZH2 protein expression associated with a BCL2 negative phenotype was observed in 43% (9/21) of the cases. BCL2 gene break or 1p36 deletion did not impact the prognosis; however, they showed association with advanced stages at diagnosis (p = 0.016) and a tendency with shorter event free survival (p = 0.052).In conclusion, 1p36 deletion co-occurs with acquired TNFRSF14 mutations, suggesting a role of this tumor suppressor gene in the development of a subgroup of PCFCL. High EZH2 protein expression associated with BCL2 negative phenotype is common and might represent an ideal therapeutic target.

[Novel method in diagnosis of chronic myeloproliferative disorders--detection of JAK2 mutation]. / Uj lehetoség a krónikus myeloproliferativ betegségek diagnosztikájában--a JAK2 mutaci6ókimutatása.

Chronic myeloproliferative disorders are clonal hematopoietic stem cell disorders characterized by proliferation of one or more myeloid cell lineages in the bone marrow. The WHO classification describes six major groups of chronic myeloproliferative disorders, as follows: chronic myeloid leukemia, chronic neutrophilic leukemia, chronic eosinophilic leukemia, polycythemia vera, essential thrombocythemia and chronic idiopathic myelofibrosis. The diagnosis of chronic myeloid leukemia and certain types of chronic eosinophilic leukemia are based on the detection of fusion genes (in chronic myeloid leukemia the BCR/ABL fusion gene, and in chronic eosinophilic leukemia the FIP1L1-PDGFRalpha gene). On the other hand molecular markers for polycythemia vera, essential thrombocythemia and chronic idiopathic myelofibrosis were lacking, making it difficult to identify these disorders clearly. The authors investigated the incidence of the newly identified somatic point mutation V617F of the Janus-2 tyrosine kinase in patients with polycythemia vera, essential thrombocythemia and myelofibrosis. Janus-2 kinase is a cytoplasmic, non-receptor protein-tyrosine kinase with a key role in signal transduction from multiple hematopoietic growth factor receptors. The mutant protein is constitutively phosphorylated and is able to activate its downstream signaling pathways in the absence of any cytokine, thereby contributing to the pathogenesis of chronic myeloproliferative disorders. The authors investigated DNA samples from 132 patients with chronic myeloproliferative disorders. The V617F mutation was detected by allele-specific polymerase chain reaction, and the patients were genotyped by a DNA tetra-primer amplification refractory mutation system assay. Approximately 73% of polycythemia vera, 60% of essential thrombocythemia and 67% of myelofibrosis showed the JAK2 V617F mutation. Using the amplification refractory mutation system assay, the frequency of homozygotes was 17.5% in polycythemia vera, 5.4% in essential thrombocythemia and 0% in myelofibrosis. The authors established an effective polymerase chain reaction based method for the identification of JAK2 mutation in the routine oncohematologic diagnostics.

[Molecular biology of CLL]. / A CLL molekuláris patológiája.

Recently, major advances have occurred in our understanding of the biology of chronic lymphocytic leukemia (CLL). CD5-positive CLL cells were once assumed to originate from immature, immunologically incompetent B lymphocytes, and to passively accumulate due to increased life time. In 1999, two research groups demonstrated that CLL, which is a morphologically uniform but clinically heterogenous disease, can be classified into two major subgroups on the basis of the mutational status of the immunoglobulin heavy chain (IgH) genes. It was also suggested that these two groups both originate from mature cells that have passed the antigen selection process. This hypothesis was confirmed by gene expression studies indicating a uniform pattern characteristic to memory cells, as well as specific B-cell receptor (BCR) structures supporting the existence of a functional antigen selection. The differences in the BCR signal transduction mechanisms may underlie the different clinical behavior in which zeta-associated tyrosine kinase (ZAP-70) may play a pivotal role, since elevated ZAP-70 expression is likely to be an unfavorable prognostic factor in CLL. The diagnostic testing for ZAP-70 expression plays an important role in the therapeutic decisions.

Mutational analysis of IgVH and BCL-6 genes suggests thymic B-cells origin of mediastinal (thymic) B-cell lymphoma.

Mediastinal (thymic) large B-cell lymphoma (MBL) has been defined as a subtype of diffuse large B-cell lymphoma (DLBL) arising in the mediastinum with characteristic clinicopathological features. It has been postulated that MBL arise from non-circulating thymic B-cells and represent a distinct lymphoma entity, however, the histogenesis of the disease is not yet fully understood. In order to clarify the histogenetic derivation of MBL and to determine the relationship of MBL to thymic B-cells we have analyzed the nucleic acid sequences of immunoglobulin (Ig) heavy chain variable region (VH) and 5' noncoding region of BCL-6 genes in normal thymic B-cells and six cases of MBL. Thymic B-cells and tumor cells of MBLs displayed hypermutated VH and/or BCL-6 genes but intraclonal divergence did not associate with these mutations. Since somatic mutations of the IgVH and BCL-6 genes are histogenetic markers of B-cell transit through the germinal centre (GC), these results suggest that both thymic B-cells and MBLs derived from GC or an equivalent environment where B-cells underwent somatic hypermutation. The similar pattern of mutations of IgVH and BCL-6 genes found in thymic B-cells and MBLs further supports the theory that MBLs originate from thymic B-cells.

Thioacetamide-induced hepatic fibrosis in transforming growth factor beta-1 transgenic mice.

OBJECTIVE: Transforming growth factor beta-1 (TGF-beta 1) is thought to be one of the most important factors affecting the development of fibrotic processes in the liver. AIM: To discover whether endogenously higher TGF-beta 1 production influences the progression and reversibility of liver fibrosis in mice. METHOD: We compared thioacetamide-induced liver fibrosis between wild-type and transgenic mice overexpressing active TGF-beta 1 in the liver. Hepatic fibrosis was detected on histological sections, and fibrotic areas were measured by means of morphometric analysis. We also performed Northern blot hybridisation and gelatine zymography to improve our understanding of the process. RESULTS: The fibrotic process was faster in the transgenic animals, and regression after the withdrawal of the fibrogenic agent was slower. Fibrosis did not disappear completely from the TGF-beta 1 overexpressing mice, even at the endpoint of the experiment. CONCLUSION: Since the increased TGF-beta 1 production in the liver slowed down the regression of the liver fibrosis, the behaviour of these transgenic mice is more similar to the human situation, where cirrhosis is irreversible. We propose that this transgenic model is more suitable for investigating fibrotic liver diseases than the experiments done previously on wild-type rodents.

Unicentric mixed variant Castleman disease associated with intrabronchial plasmacytoma.

Castleman disease (CD), described as a heterogeneous lymphoproliferative disorder, can be divided into different subtypes according to clinical appearance (unicentric and multicentric form) and histopathological features (hyaline vascular, plasma cell, mixed type, human herpesvirus 8-associated and multicentric not otherwise specified). Unicentric CD is known to be usually of the hyaline vascular variant, plasma cell and mixed type of this form are quite uncommon. Malignancies are mainly associated with the multicentric form. We report a rare case of unicentric mixed variant CD evolving into intrabronchial, extramedullary plasmacytoma.Intrabronchial mass with consequential obstruction of the left main bronchus, left lung atelectasis and mediastinal lymphadenomegaly was detected by chest CT in our patient suffering from cough and hemoptysis. Pulmonectomy was performed, histopathological and immunhistochemical analysis of lymph nodes revealed mixed type of CD with interfollicular monotypic plasma cell proliferation. The intrabronchial mass consisted of monotypic plasma cells confirming plasmacytoma. Systemic involvement was not confirmed by further tests.Although malignancies more often present in multicentric CD that usually belongs to the plasma cell subtype, this case confirms the neoplastic potential of the rarest, unicentric mixed variant of CD. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2872096831190851.

The density of CD8+ T-cell infiltration and expression of BCL2 predicts outcome of primary diffuse large B-cell lymphoma of bone.

Primary bone lymphoma (PBL) comprises 5 % of all extranodal non-Hodgkin's lymphomas (NHLs). Diffuse large B-cell lymphoma (DLBCL) accounts for the majority of cases, which is the most heterogeneous group of lymphomas. Previous studies suggested that besides the tumor cell phenotype, phosphatidylinositol 3-kinase/acutely transforming retrovirus/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway activity and the composition of the immune-microenvironment of DLBCL influence the clinical behavior of the disease. The aim of our study was to determine the relationship between clinical factors, tumor cell phenotype, microenvironment, PI3K/AKT/mTOR pathway activity, and disease outcome in primary bone diffuse large B-cell lymphoma (PB-DLBCL). We constructed tissue-microarrays from 41 cases of PB-DLBCL. To characterize tumor cell phenotype, T-cell subsets, macrophages, and PI3K/AKT/mTOR pathway activity immunohistochemical stainings were evaluated. Kaplan-Meier survival analysis provided evidence that age (≤65), CD3 and CD8+ T cell infiltrations >5 %, low BCL2 expression of the tumor cells (≤30 %), and low proliferation index (Ki67 ≤ 57 %) were associated with favorable outcome of PB-DLBCL patients. Multivariate analysis revealed that CD8+ T cell infiltration >5 % and low BCL2 expression (≤30 %) were independent predictors of survival. Increased macrophage infiltration (>10 %) showed tendency toward an adverse prognostic effect. International prognostic index, tumor cell phenotype (GCB or ABC), MYC protein expression, and activation of PI3K/AKT/mTOR pathway had no significant impact on survival. However, mTOR activity showed a significant correlation with activated B-cell phenotype. We conclude that CD8 and BCL2 expressions are potential prognostic markers for PB-DLBCL patients and the PI3K/AKT/mTOR pathway appears to be an additional therapeutic target in PB-DLBCL with activated-B-cell phenotype.

Nuclear factor-κB activation in primary lymphoma of bone.

Primary lymphoma of bone is a rare type of extranodal diffuse large B-cell lymphoma with a relatively favourable outcome. Recent scientific interest has focused on elucidating the role of nuclear factor-κB pathway in lymphomagenesis and its potential significance as a therapeutic target. In nodal B-cell non-Hodgkin lymphomas, constitutive activation of nuclear factor-κB appears to be involved in tumour cell survival, notably in the non-germinal centre type of diffuse large B-cell lymphoma. We investigated nuclear factor-κB activation via the classical and alternative pathway in primary lymphoma of bone, through immunohistochemical staining for nuclear factor-κB family members on tumour tissues of 50 patients. Nine cases (18 %) showed nuclear staining for p50, and one case showed nuclear co-expression of p52. None of the cases showed nuclear staining for c-Rel. The nuclear staining of p50 suggests that in a minority of primary lymphomas of bone nuclear factor-κB is constitutively activated via the classical pathway. In contrast to other extranodal types of diffuse large B-cell lymphoma, there was a lack of nuclear co-expression of p65, which might suggest activation of a different pathway. Activation of nuclear factor-κB through the alternative pathway does not appear to be significantly involved, as only one case showed significant nuclear expression for p52. Finally, nuclear expression of p50 was neither preferentially detected in non-germinal centre type or germinal centre type primary lymphoma of bone, nor related to poor prognosis. Therefore, in contrast to nodal diffuse large B-cell lymphoma, the nuclear factor-κB pathway does not appear to be an attractive therapeutic target in primary lymphoma of bone.