High PTX3 expression is associated with a poor prognosis in diffuse large B-cell lymphoma.

Tumor-associated macrophages (TAMs) are associated with a poor prognosis of diffuse large B-cell lymphoma (DLBCL). As macrophages are heterogeneous, the immune polarization and their pathological role warrant further study. We characterized the microenvironment of DLBCL by immunohistochemistry in a training set of 132 cases, which included 10 Epstein-Barr virus-encoded small RNA (EBER)-positive and five high-grade B-cell lymphomas, with gene expression profiling in a representative subset of 37 cases. Diffuse large B-cell lymphoma had a differential infiltration of TAMs. The high infiltration of CD68 (pan-macrophages), CD16 (M1-like), CD163, pentraxin 3 (PTX3), and interleukin (IL)-10-positive macrophages (M2c-like) and low infiltration of FOXP3-positive regulatory T lymphocytes (Tregs) correlated with poor survival. Activated B cell-like DLBCL was associated with high CD16, CD163, PTX3, and IL-10, and EBER-positive DLBCL with high CD163 and PTX3. Programmed cell death-ligand 1 positively correlated with CD16, CD163, IL-10, and RGS1. In a multivariate analysis of overall survival, PTX3 and International Prognostic Index were identified as the most relevant variables. The gene expression analysis showed upregulation of genes involved in innate and adaptive immune responses and macrophage and Toll-like receptor pathways in high PTX3 cases. The prognostic relevance of PTX3 was confirmed in a validation set of 159 cases. Finally, in a series from Europe and North America (GSE10846, R-CHOP-like treatment, n = 233) high gene expression of PTX3 correlated with poor survival, and moderately with CSF1R, CD16, MITF, CD163, MYC, and RGS1. Therefore, the high infiltration of M2c-like immune regulatory macrophages and low infiltration of FOXP3-positive Tregs is associated with a poor prognosis in DLBCL, for which PTX3 is a new prognostic biomarker.

Anti-HBV drug entecavir ameliorates DSS-induced colitis through PD-L1 induction.

PD-L1-mediated signaling is one of the major processes that regulate local inflammatory responses in the gut. To date, protective effects against colitis through direct Fc-fused PD-L1 administration or indirect PD-L1 induction by probiotics have been reported. We have previously shown that the anti-HBV drug entecavir (ETV) induces PD-L1 expression in human hepatocytes. In the present study, we investigated whether ETV induces PD-L1 expression in intestinal cells and provides a protective effect against DSS-induced colitis. ETV induced PD-L1 expression in epithelial cells, rather than T and B cells, improving the symptoms of colitis. In the mechanistic analysis, Th17 cell differentiation was inhibited and B cell infiltration into the lamina propria was reduced. In addition, PD-L1 expression was positively correlated with Foxp3 or CSF1-R. In conclusion, ETV upregulated PD-L1 expression in epithelial cells and ameliorated inflammation in DSS-induced colitis. These results suggest that ETV may be a potential therapeutic agent as a PD-L1 enhancer for the treatment of human IBD.

The multilobated morphology is still a better prognosis factor of diffuse large B-cell lymphoma in the R-CHOP era.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of B-cell lymphoma. Although the multilobated subtype of DLBCL has been observed since the 1970s, little is known about the clinical significance of this unique variant in the era of rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin, prednisone/prednisolone (R-CHOP) therapy. In this study, the retrospective clinicopathological analysis of 312 patients diagnosed with DLBCL showed that the multilobated DLBCL group comprised 11% of the cases and was predominantly male (p = 0.027), achieved complete remission in the first therapy (p = 0.023), and exhibited germinal center B-cell phenotypes in the Hans algorithm (p = 0.025). The multilobated DLBCL groups had a better prognosis in overall survival (OS) and progression-free survival (PFS) than the non-multilobated DLBCL group (OS, p = 0.006; PFS, p = 0.010). In the multivariate Cox regression analyses for OS, independent prognosis factors were high soluble IL-2 receptor (p = 0.025), high risk of International Prognostic Index, and multilobated morphology (p = 0.031). The most characteristic copy number gains found in more than 50% of the cases were located at 1q, 3p, 10q, 12q, and 14q. Overall, the multilobated morphology in DLBCL exhibits a good outcome in the R-CHOP era.

AID is a poor prognostic marker of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements.

Diffuse large B-cell lymphoma with MYC rearrangement is defined as double/triple-hit lymphoma (DHL/THL) or single-hit lymphoma (SHL) by the inclusion of the BCL2 and BCL6 rearrangements status. DHL/THL is called as "high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements" in the World Health Organization 2017 Classification of Tumors of Hematopoietic and Lymphoid Tissues. To find a prognostic biomarker of DHL/THL, we firstly examined 19 cases (molecular analysis series;10 cases of DHL/THL and 9 cases of SHL) with gene expression profile analysis. The gene expression profile analysis showed that the high expression of AICDA was associated with an adverse prognosis in DHL/THL, but not in SHL. Then, we evaluated immunohistochemical expression of AID, the protein product of AICDA, in 50 cases (molecular analysis series of 19 cases and additional immunohistochemistry series of 31 cases; 12 cases of DHL/THL and 19 cases of SHL) and confirmed that its expression was also associated with an adverse prognosis in DHL/THL. Therefore, AICDA and AID can be a predictor of an adverse clinical outcome in DHL/THL and immunohistochemistry of AID is useful to find DHL/THL-adverse prognosis group.

Clinical outcome of Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly in the rituximab era.

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of malignant lymphoma. The incidence of Epstein-Barr virus (EBV)-positive DLBCL in Asian and Latin American countries ranges from 8 to 10%. The prognosis of patients with EBV-positive DLBCL is controversial. To compare the clinical outcome of EBV-positive and EBV-negative patients with DLBCL in the rituximab era, we analyzed 239 patients with de novo DLBCL diagnosed between January 2007 and December 2011. The presence of EBV in lymphoma cells was detected using EBV-encoded RNA in situ hybridization, and it was found that 18 (6.9%) of 260 patients with diagnosed DLBCL tested positive. Among the 260 cases, 216 cases were treated with rituximab plus chemotherapy, as were 8 EBV-positive DLBCL patients. The median overall survival and progression-free survival times in patients with EBV-positive DLBCL were 8.7 months and 6.8 months, respectively. The median overall survival and progression-free survival could not be determined in EBV-negative DLBCL patients (P = 0.0002, P < 0.0001, respectively). The outcome of patients with EBV-positive DLBCL remains poor, even in the rituximab era.

Mutational, immune microenvironment, and clinicopathological profiles of diffuse large B-cell lymphoma and follicular lymphoma with BCL6 rearrangement.

BCL6-rearrangement (BCL6-R) is associated with a favorable prognosis of follicular lymphoma (FL), but the mechanism is unknown. We analyzed the clinicopathological, immune microenvironment (immune checkpoint, immuno-oncology markers), and mutational profiles of 10 BCL6-R-positive FL, and 19 BCL6-R-positive diffuse large B-cell lymphoma (DLBCL) cases (both BCL2-R and MYC-R negative). A custom-made panel included 168 genes related to aggressive B-cell lymphomas and FL. FL cases were nodal, histological grade 3A in 70%, low Ki67; and had a favorable overall and progression-free survival. DLBCL cases were extranodal in 60%, IPI high in 63%, non-GCB in 60%, EBER-negative; and had a progression-free survival comparable to that of DLBCL NOS. The microenvironment had variable infiltration of M2-like tumor-associated macrophages (TAMs) that were CD163, CSF1R, LAIR1, PD-L1, and CD85A (LILRB3) positive; but had low IL10 and PTX3 expression. In comparison to FL, DLBCL had higher TAMs, IL10, and PTX3 expression. Both lymphoma subtypes shared a common mutational profile with mutations in relevant pathogenic genes such as KMT2D, OSBPL10, CREBBP, and HLA-B (related to chromatin remodeling, metabolism, epigenetic modification, and antigen presentation). FL cases were characterized by a higher frequency of mutations of ARID1B, ATM, CD36, RHOA, PLOD2, and PRPRD (p < 0.05). DLBCL cases were characterized by mutations of BTG2, and PIM1; and mutations of HIST1H1E and MFHAS1 to disease progression (p < 0.05). Interestingly, mutations of genes usually associated with poor prognosis, such as NOTCH1/2 and CDKN2A, were infrequent in both lymphoma subtypes. Some high-confidence variant calls were likely oncogenic, loss-of-function. MYD88 L265P gain-of-function was found in 32% of DLBCL. In conclusion, both BCL6-R-positive FL and BCL6-R-positive DLBCL had a common mutational profile; but also, differences. DLBCL cases had a higher density of microenvironment markers.

Over-expression of BACH2 is related to ongoing somatic hypermutation of the immunoglobulin heavy chain gene variable region of de novo diffuse large B-cell lymphoma.

The basic region-leucine zipper (bZip) factor BTB, CNC homology 2 (BACH2) is known to have important roles in class switch recombination and somatic hypermutation (SHM) of the immunoglobulin (Ig) gene. In this study, we investigated the relationship between the expression of BACH2 and the status of SHM of the Ig heavy chain gene variable region (IgHV) for SHM in diffuse large B-cell lymphoma (DLBCL). We examined 20 cases of DLBCL, 13 of which were germinal center B-cell (GCB) DLBCL and 7 were non-GCB DLBCL. Seven cases were negative, 6 were positive (cytoplasmic expression) and 7 were strongly positive (both nuclear and cytoplasmic expression) for BACH2. Confirmed mutation (CM) was identified in 8 cases and the CM index (number of confirmed mutations per 10 subclones) was distributed from 0 to 5. A CM index of 7 strongly positive (over-expression) cases with BACH2 were distributed from 0 to 5, and that of 7 negative and 6 positive cases were distributed from 0 to 1. Over-expression of BACH2 was statistically related to CM index (P = 0.008). In conclusion, over-expression of BACH2 is critical for ongoing SHM of IgHV in DLBCL, and our data suggest that BACH2 may play an essential role for SHM of the Ig gene in B-cell lymphoma.

Mutational Profile and Pathological Features of a Case of Interleukin-10 and RGS1-Positive Spindle Cell Variant Diffuse Large B-Cell Lymphoma.

Diffuse large B-cell lymphoma with spindle cell morphology is a rare variant. We present the case of a 74-year-old male who initially presented with a right supraclavicular (lymph) node enlargement. Histological analysis showed a proliferation of spindle-shaped cells with narrow cytoplasms. An immunohistochemical panel was used to exclude other tumors, such as melanoma, carcinoma, and sarcoma. The lymphoma was characterized by a cell-of-origin subtype of germinal center B-cell-like (GCB) based on Hans' classifier (CD10-negative, BCL6-positive, and MUM1-negative); EBER negativity, and the absence of BCL2, BCL6, and MYC rearrangements. Mutational profiling using a custom panel of 168 genes associated with aggressive B-cell lymphomas confirmed mutations in ACTB, ARID1B, DUSP2, DTX1, HLA-B, PTEN, and TNFRSF14. Based on the LymphGen 1.0 classification tool, this case had an ST2 subtype prediction. The immune microenvironment was characterized by moderate infiltration of M2-like tumor-associated macrophages (TMAs) with positivity of CD163, CSF1R, CD85A (LILRB3), and PD-L1; moderate PD-1 positive T cells, and low FOXP3 regulatory T lymphocytes (Tregs). Immunohistochemical expression of PTX3 and TNFRSF14 was absent. Interestingly, the lymphoma cells were positive for HLA-DP-DR, IL-10, and RGS1, which are markers associated with poor prognosis in DLBCL. The patient was treated with R-CHOP therapy, and achieved a metabolically complete response.

Thymic Dedifferentiated Liposarcoma Having a Leiomyosarcomatous Dedifferentiated Component.

We report an extremely rare case of 42-year-old man, d iagnosed with thymic dedifferentiated liposarcoma (DDL) having a leiomyosarcomatous dedifferentiated component. The tumor was composed of atypical spindle cells. The morphological atypia was also observed around thymic adipose tissue. Immunohistochemically, the spindle cells were positive for desmin, smooth muscle actin, MDM2 and CDK4. MDM2 and CDK4 were also positive for the thymic adipose tissue. MDM2 amplification was confirmed by fluorescence in situ hybridization. Although there are some reports of mediastinal leiomyosarcoma, DDL may be overlooked. For accurate diagnosis of mediastinal mesenchymal tumor, careful observation of thymic adipose tissue is required with immunohistochemical study.

Copy Number Alteration and Mutational Profile of High-Grade B-Cell Lymphoma with MYC and BCL2 and/or BCL6 Rearrangements, Diffuse Large B-Cell Lymphoma with MYC-Rearrangement, and Diffuse Large B-Cell Lymphoma with MYC-Cluster Amplification.

Diffuse large B-cell lymphoma (DLBCL) with MYC alteration is classified as high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (double/triple-hit lymphoma; DHL/THL), DLBCL with MYC rearrangement (single-hit lymphoma; SHL) and DLBCL with MYC-cluster amplification (MCAD). To elucidate the genetic features of DHL/THL, SHL, and MCAD, 23 lymphoma cases from Tokai University Hospital were analyzed. The series included 10 cases of DHL/THL, 10 cases of SHL and 3 cases of MCAD. The analysis used whole-genome copy number microarray analysis (OncoScan) and a custom-made next-generation sequencing (NGS) panel of 115 genes associated with aggressive B-cell lymphomas. The copy number alteration (CNA) profiles were similar between DHL/THL and SHL. MCAD had fewer CNAs than those of DHL/THL and SHL, except for +8q24. The NGS profile characterized DHL/THL with a higher "mutation burden" than SHL (17 vs. 10, p = 0.010), and the most relevant genes for DHL/THL were BCL2 and SOCS1, and for SHL was DTX1. MCAD was characterized by mutations of DDX3X, TCF3, HLA-A, and TP53, whereas MYC was unmutated. In conclusion, DHL/THL, SHL, and MCAD have different profiles.

9p24.1 Genetic Alteration and PD-L1 Expression Are Characteristic of De Novo and Methotrexate-associated Epstein-Barr Virus-positive Hodgkin Lymphoma, But Not Methotrexate-associated Hodgkin-like Lesions.

Although the alteration of the 9p24.1 chromosome locus and PD-L1 overexpression is found in nodular sclerosis classic Hodgkin lymphoma, whether these aberrations occur in CHL and Hodgkin-like lesion (HLL) of methotrexate-associated lymphoproliferative disorder (MTX-CHL and MTX-HLL) is unknown. We compared the clinicopathologic features, the genomic status of the 9p24.1 locus and PD-L1 expression in a series of 34 patients including 17 with Epstein-Barr virus-positive de novo CHL, 7 with MTX-CHL, 10 with MTX-HLL using an immunofluorescence in situ hybridization method and immunohistochemistry. The proportions of cells with 9p24.1 genetic alteration in CD30-positive Hodgkin/Reed-Sternberg cells of de novo CHL, MTX-CHL and MTX-HLL were 55%, 68%, and 24%, respectively. The positive rates of PD-L1 measured by immunohistochemical H-scores of de novo CHL, MTX-CHL and MTX-HLL were 142±38, 157±75, and 70±42, respectively. Alteration of the 9p24.1 gene and expression of PD-L1 protein were correlated with all 3 diseases (correlation coefficient, 0.731). Both alteration of the 9p24.1 gene and overexpression of PD-L1 protein were observed in Epstein-Barr virus-positive de novo CHL and MTX-CHL but not in MTX-HLL. In conclusion, MTX-CHL has similar pathogenesis-like de novo CHL, but MTX-HLL seems to be a different disease from de novo CHL and MTX-CHL.

Germinal center B-cell-like diffuse large B-cell lymphoma of the duodenum is associated with t(14;18) translocation.

Diffuse large B-cell lymphoma (DLBCL) rarely involves the duodenum, and its clinicopathological characteristics have not been well elucidated. We performed clinicopathological examinations and identified 15 patients with duodenal DLBCL using 18 gastric or colonic DLBCL as a control. Eleven of the 15 patients (73%) were subclassified by immunohistochemical analysis according to the Choi algorithm as germinal center B-cell-like (GCB) type, whereas the 18 control gastric and colonic DLBCL were predominantly subclassified as activated B-cell-like (ABC) type. The classifications according to organ involvement were statistically significant (P= 0.011 and P= 0.035). Macroscopically, the GCB lesions were varied, while all ABC lesions were ulcerative. Fluorescence in situ hybridization analysis revealed a higher frequency of t(14;18) translocation in patients with duodenal DLBCL (3 of 13) as compared with non-duodenal gastrointestinal tract DLBCL (0 of 18), however, the difference was not significant (P = 0.064). Furthermore, the three patients with t(14;18) translocations were classified as GCB. In addition, overall survival of patients was statistically different between those with and without t(14;18) translocation (P= 0.040). In conclusion, duodenal DLBCL predominantly exhibits GCB-type tumors and the frequency of t(14;18) translocation appears to be higher in duodenal GCB-type DLBCL compared to non-duodenal tumors.

Artificial Neural Networks Predicted the Overall Survival and Molecular Subtypes of Diffuse Large B-Cell Lymphoma Using a Pancancer Immune-Oncology Panel.

Diffuse large B-cell lymphoma (DLBCL) is one of the most frequent subtypes of non-Hodgkin lymphomas. We used artificial neural networks (multilayer perceptron and radial basis function), machine learning, and conventional bioinformatics to predict the overall survival and molecular subtypes of DLBCL. The series included 106 cases and 730 genes of a pancancer immune-oncology panel (nCounter) as predictors. The multilayer perceptron predicted the outcome with high accuracy, with an area under the curve (AUC) of 0.98, and ranked all the genes according to their importance. In a multivariate analysis, ARG1, TNFSF12, REL, and NRP1 correlated with favorable survival (hazard risks: 0.3-0.5), and IFNA8, CASP1, and CTSG, with poor survival (hazard risks = 1.0-2.1). Gene set enrichment analysis (GSEA) showed enrichment toward poor prognosis. These high-risk genes were also associated with the gene expression of M2-like tumor-associated macrophages (CD163), and MYD88 expression. The prognostic relevance of this set of 7 genes was also confirmed within the IPI and MYC translocation strata, the EBER-negative cases, the DLBCL not-otherwise specified (NOS) (High-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements excluded), and an independent series of 414 cases of DLBCL in Europe and North America (GSE10846). The perceptron analysis also predicted molecular subtypes (based on the Lymph2Cx assay) with high accuracy (AUC = 1). STAT6, TREM2, and REL were associated with the germinal center B-cell (GCB) subtype, and CD37, GNLY, CD46, and IL17B were associated with the activated B-cell (ABC)/unspecified subtype. The GSEA had a sinusoidal-like plot with association to both molecular subtypes, and immunohistochemistry analysis confirmed the correlation of MAPK3 with the GCB subtype in another series of 96 cases (notably, MAPK3 also correlated with LMO2, but not with M2-like tumor-associated macrophage markers CD163, CSF1R, TNFAIP8, CASP8, PD-L1, PTX3, and IL-10). Finally, survival and molecular subtypes were successfully modeled using other machine learning techniques including logistic regression, discriminant analysis, SVM, CHAID, C5, C&R trees, KNN algorithm, and Bayesian network. In conclusion, prognoses and molecular subtypes were predicted with high accuracy using neural networks, and relevant genes were highlighted.

A case of JAK2V617F-positive essential thrombocythemia where allele burden was reduced by a PD-1 inhibitor.

The Janus kinase/signal transducers and activators of transcription signaling pathway induces programmed death ligand-1 (PD-L1) expression. JAK2 mutation at position 617 (JAK2V617) is a frequent driver of myeloproliferative neoplasms (MPN) through PD-L1 expression. Although PD-1 inhibitors should be effective against MPN with JAK2V617F mutation, this has not yet been reported in humans. Thus, we assessed the efficacy of a PD-1 inhibitor in a lung cancer patient with JAK2V617F-positive essential thrombocythemia (ET). A 71-year-old man was diagnosed with ET, and with lung carcinoma 3 years later. After right lobectomy and postoperative chemotherapy, pembrolizumab [a PD-1 inhibitor (200 mg, every 3 weeks)] was initiated for refractory lung carcinoma. Lung cancer progression did not occur for 1.5 years under treatment. Most megakaryocytes were PD-L1-positive, and after pembrolizumab initiation, platelet count remained below 45 × 104/µL without the need for other cytoreductive therapies for ET. The JAK2V617F allele burden gradually decreased from 11.5% at diagnosis to 2.9% after 17 months of pembrolizumab treatment. Other peripheral blood lineages did not decrease, and pembrolizumab treatment was continued without any adverse events. This is the first report demonstrating the effectiveness of pembrolizumab in an MPN patient with JAK2V617F mutation.

Clinicopathological features of adult T-cell leukemia/lymphoma with HTLV-1-infected Hodgkin and Reed-Sternberg-like cells.

Hodgkin and Reed-Sternberg (HRS) cells, a hallmark of classic Hodgkin lymphoma (CHL), are occasionally detected in non-Hodgkin lymphomas, including adult T-cell leukemia/lymphoma (ATLL), a lymphoid neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1). HRS-like cells associated with ATLL have been described to be of B-cell lineage and infected with Epstein-Barr virus (EBV), not HTLV-1. We herein describe clinicopathological findings in 8 cases (4 males and 4 females; median age, 73 years [range, 55-81 years]) of ATLL with HTLV-1-infected HRS-like cells identified by ultrasensitive RNA in situ hybridization for HTLV-1 basic leucine zipper factor (HBZ-ISH), a specific viral transcript of HTLV-1. All patients showed nodal or mediastinal lesions, and 5 of the 8 patients were at an advanced disease stage. HRS-like cells were positive for CD30, CD15, MUM1, CD25, and HBZ-ISH and negative for B-cell markers, including PAX5, pan-T-cell antigens, and EBV in all cases. Five cases were positive for CD4, and 6 cases were positive for fascin. HBZ was identified in both HRS-like cells and surrounding lymphoid cells in 1 case with an aggressive clinical course and only HRS-like cells in 7 cases, most of whom showed a clinical response regardless of the chemotherapeutic regimen. Even though the definitive lineage typing of the HTLV-1-infected HRS cells is one of the limitations of this study in the absence of single-cell microdissection for polymerase chain reaction analysis, the combination of diffuse HBZ-ISH positivity and negativity for PAX5 and EBV deemed these cases distinct from CHL arising in HTLV-1 carriers.

Methotrexate-associated lymphoproliferative disorder demonstrating composite lymphoma of EBV-negative diffuse large B-cell lymphoma and EBV-positive mucocutaneous ulcer.

Other iatrogenic immunodeficiency-associated lymphoproliferative disorders induced by immunosuppressive drugs, such as methotrexate (MTX-LPD), exhibit numerous pathological findings. We report the case of an 81-year-old Japanese woman diagnosed with MTX-LPD exhibiting two distinct pathological features from two different sites. Excisional biopsy of the left cervical lymph node revealed EBV-negative diffuse large B-cell lymphoma and biopsy of a pharyngeal ulcer revealed EBV-positive mucocutaneous ulcer. She was treated using an R-CHOP regimen and maintained complete remission for years. This case demonstrates the heterogeneous pathology of MTX-LPD and suggests the necessity of multiple biopsy.

Monomorphic Epitheliotropic Intestinal T-Cell Lymphoma in Asia Frequently Shows SETD2 Alterations.

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare primary T-cell lymphoma of the digestive tract derived from intraepithelial lymphocytes and characterized by an aggressive clinical course. In this study, nine cases of Japanese MEITL were analyzed by targeted Next Generation Sequencing (NGS) and immunohistochemistry and were integrated with previously reported whole-genome copy number microarray-based assay data. The highlight of our findings is that all cases showed alterations of the tumor suppressor gene SETD2 by mutations and/or loss of the corresponding 3p21 locus. We also demonstrated that all cases showed mutations in one or more genes of JAK/STAT pathway. Therefore, the combination of epigenetic deregulation and cell signaling activation represent major oncogenic events in the pathogenesis of MEITL in Asian MEITL, similar to Western MEITL.

Clinicopathological evaluation of methotrexate-associated lymphoproliferative disorders with special focus on Epstein-Barr virus-positive mucocutaneous lesions.

Some patients diagnosed with methotrexate-associated lymphoproliferative disorder (MTX-LPD) develop spontaneous regression upon the discontinuation of MTX, whereas others require chemotherapy. The mechanisms underlying this differential response and the capacity to spontaneously regress are not clearly understood. We evaluated numerous clinicopathological features in 63 patients diagnosed with MTX-LPD, with a special focus on those with Epstein-Barr virus (EBV)-positive mucocutaneous lesions (EBVMCL). The diagnosis of EBVMCL included cases of both EBV-positive mucocutaneous ulcers (EBVMCU) and diffuse gingival swelling associated with proliferation of EBV-positive large B-cells. Of the four subgroups of MTX-LPD, one-year treatment-free survival (TFS) after the discontinuation of MTX was achieved among those with EBVMCL (100%), diffuse large B-cell lymphoma (57%), Hodgkin-like lesions (60%), or classical Hodgkin lymphoma (29%); a significant difference in TFS was observed when comparing the responses of patients with EBVMCL to the those diagnosed with other subtypes. Multivariate analysis revealed predictive factors for prolonged TFS that included EBV-positive lesions and comparatively low levels of serum LDH. Taken together, our study suggests that a diagnosis of EBVMCL is related to the overall clinical outcome after the discontinuation of MTX.

Dasatinib exacerbates splenomegaly of mice inoculated with Epstein-Barr virus-infected lymphoblastoid cell lines.

Latent infection of Epstein-Barr virus (EBV) is associated with a poor prognosis in patients with B cell malignancy. We examined whether dasatinib, a multi kinase inhibitor, which is broadly used for chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia is effective on EBV-positive B cell malignancies, using lymphoblastoid cell lines (LCLs) in vitro and in vivo. As a result, in vitro experiments showed that dasatinib induced cell death of the EBV-LCLs which was not accompanied with a lytic reactivation of EBVs. To evaluate the effectiveness in EBV latency type III represented by immunodeficiency lymphoma, LCL-inoculated immunodeficient NOD/shi-scid/Il2rgnul (NOG) mice were treated with dasatinib. However, in vivo experiments revealed that dasatinib treatment exacerbated tumor cell infiltration into the spleen of LCL-inoculated NOG mice, whereas tumor size at the inoculated site was not affected by the treatment. These results suggest that dasatinib exacerbates the pathogenesis at least in some situations although the drug is effective in vitro. Hence, we should carefully examine a possibility of dasatinib repositioning for EBV+ B cell malignancies.