Tomoko Miyata-Takata

T-cell receptor (TCR) phenotype of nodal Epstein-Barr virus (EBV)-positive cytotoxic T-cell lymphoma (CTL): a clinicopathologic study of 39 cases.

Among Epstein-Barr virus (EBV)-positive cytotoxic T/NK-cell lymphoma, there are only a few reports on the clinicopathologic features of patients with primary nodal presentation (nodal EBV+ cytotoxic T-cell lymphoma [CTL]). Here, we compared the clinicopathologic profiles of 39 patients with nodal EBV+ CTL with those of 27 cases of “extranasal” NK/T-cell lymphoma of nasal type (ENKTL), especially addressing their T-cell receptor (TCR) phenotype. Histologically, 22 of 39 nodal EBV+ CTL cases (56%) were unique in having centroblastoid appearance, which was contrasted with the lower incidence of this feature in ENKTL (15%, P=0.001). In contrast, pleomorphic appearance was more frequently seen in ENKTL than in nodal EBV+ CTL (67% vs. 23%, P=0.001). Thirty-three of 39 nodal EBV+ CTL cases (85%) were of T-cell lineage on the basis of TCR expression and/or TCR&ggr; gene rearrangement; in detail, 18 cases (46%) were TCR&bgr; positive (&agr;&bgr; T), 5 (13%) were TCR&ggr; and/or &dgr; positive (&ggr;&dgr; T), and 10 (26%) were TCR-silent type with clonal TCR&ggr; gene rearrangement but no expression of TCR&bgr;, &ggr;, or &dgr;. These results were clearly contrasted by a lower incidence of T-cell lineage in ENKTL (7 cases, 26%, P<0.001). Notably, the survival time of the 5 nodal lymphoma patients with &ggr;&dgr; T-cell phenotype was within 3 months, which was inferior to those of &agr;&bgr; T and TCR-silent types (P=0.003), and 3 of those with available clinical information were all found to be associated with autoimmune diseases. These data suggest that nodal EBV+ CTL is distinct from ENKTL.

Frequent MYD88 L265P and CD79B Mutations in Primary Breast Diffuse Large B-Cell Lymphoma.

Primary breast diffuse large B-cell lymphoma (PB-DLBCL) is a rare disease comprising <3% of extranodal lymphomas. It frequently reveals an activated B-cell (ABC)-like phenotype. ABC-like DLBCL was reported to have gain-of-function mutations in MYD88, CD79B, CARD11, and TNFAIP3, resulting in constitutive activation of the NF&kgr;B pathway. Because of the rare occurrence of PB-DLBCL, the frequency of MYD88 and CD79B mutations is still unknown. We used Sanger sequencing to study these mutations from 46 breast DLBCL cases and also investigated the associated clinicopathologic factors. MYD88 L265P was confirmed by allele-specific polymerase chain reaction and compared with the Sanger sequencing results. MYD88 L265P and CD79B mutations were detected in 27/46 (58.7%) and 11/33 (33.3%) cases, respectively. Twenty-eight of 46 cases met the criteria for PB-DLBCL, and the latter 18 cases were further classified as clinical breast DLBCL (CLB-DLBCL). The frequency of MYD88 L265P and CD79B mutations was 16/28 (57.1%) and 9/23 (39.1%), respectively, in PB-DLBCL and 11/18 (61.1%) and 2/10 (20%), respectively, in CLB-DLBCL. When the cutoff value was set at &Dgr;Ct⩽1, the result of allele-specific polymerase chain reaction for MYD88 corresponded to those of the Sanger sequence at 92.6% sensitivity and 100% specificity. According to Choi’s algorithm, 16/27 (59.3%) demonstrated an ABC-like phenotype in PB-DLBCL, and 15/18 (83.3%) demonstrated an ABC-like phenotype in CLB-DLBCL. In conclusion, MYD88 L265P and CD79B mutations were frequently detected in PB-DLBCL, and they may be key molecules associated with PB-DLBCL lymphomagenesis. Further analysis will be required to clarify the mechanism of its pathogenesis.

A subset of ocular adnexal marginal zone lymphomas may arise in association with IgG4-related disease

We previously suggested a relationship between ocular immunoglobulin (Ig)G4-related disease (IgG4-RD) and marginal zone lymphomas (MZLs). However, the cytokine background associated with these disorders and whether it differs between ocular adnexal MZLs with (IgG4-associated MZL) and without (IgG4-negative MZL) numerous IgG4+ plasma cells are unknown. In this study, we identified the mRNA expression pattern of Th2 and regulatory T-cell (Treg) cytokines in IgG4-RD and in IgG4-associated MZL and IgG4-negative MZL using real-time polymerase chain reaction analysis. Ocular IgG4-RD and IgG4-associated MZL exhibited significantly higher expression ratios of interleukin (IL)-4/β-actin, IL-10/β-actin, IL-13/β-actin, transforming growth factor (TGF) β1/β-actin, and FOXP3/β-actin than did IgG4-negative MZL (p < 0.05). This finding further supports our prior observations that a significant subset of ocular MZLs arises in the setting of IgG4-RD. Furthermore, the presence of a different inflammatory background in IgG4-negative MZLs suggests that IgG4-associated MZLs may have a different pathogenesis.

Detection of T-cell receptor γ gene rearrangement in paraffin-embedded T or natural killer/T-cell lymphoma samples using the BIOMED-2 protocol

Abstract While the use of polymerase chain reaction (PCR)-based clonality analysis of formalin-fixed paraffin-embedded (FFPE) tissue has recently become widespread, the detection sensitivity for lymphoma subtypes using FFPE samples is not well known. Here, we analyzed T-cell receptor γ chain (TCRG) gene rearrangement clonality in 100 cases of T- or natural killer (NK)/T-cell lymphoma and examined detection sensitivity according to lymphoma subtype. Clonality was detected in approximately 80% of the major T-cell lymphoma subtypes: peripheral T-cell lymphoma, not otherwise specified, 84% (21/25 cases); angioimmunoblastic T-cell lymphoma, 71% (15/21 cases); and adult T-cell leukemia/lymphoma, 80% (8/10 cases). The number of clonal peaks differed according to subtype. TCRG gene rearrangement was not detected in 63 cases of B-cell lymphoma or reactive lesions. Thus, clonality analysis can effectively and reliably detect TCRG gene rearrangement in T-cell lymphoma cases and could, therefore, be a useful diagnostic tool in routine practice.

A case of diffuse large B-cell lymphoma transformed from primary duodenal follicular lymphoma

Primary intestinal follicular lymphoma (FL) is a variant of FL characterized by frequent duodenal involvement and a very indolent clinical behavior without therapy. Unlike nodal FL, there have been no reports of histologic transformation (HT) or death attributable to primary intestinal FL. Here, we report the first case of primary duodenal FL showing HT. A Grade 1 FL in the duodenum was incidentally detected in a 73‐year‐old man. A watch‐and‐wait strategy was adopted because the disease was stage IE. Six months later, bone marrow involvement was suspected. The intestinal lesions had not changed during the first year since the initial diagnosis. Sixty‐two months after the initial diagnosis, a biopsy specimen showed diffuse large B‐cell lymphoma (DLBCL). A perforation of the intestine occurred before chemotherapy was started. Partial resection was performed and subsequent chemotherapy was administered. The clone of the initial FL and DLBCL were identical according to PCR analysis, indicating that the primary intestinal FL had transformed into DLBCL. Although HT is rare, it could occur in some patients with primary intestinal FL. Based on this case, it may be necessary to re‐evaluate the clinical watch‐and‐wait strategy for primary intestinal FL in some patients.

Clinicopathological analysis of 12 patients with Epstein-Barr virus-positive primary intestinal T/natural killer-cell lymphoma (EBV+ ITNKL)

Epstein–Barr virus‐positive (EBV+) intestinal T/natural killer (NK) cell lymphoma (ITNKL) is an uncommon tumour with an extremely aggressive clinical behaviour. However, the clinicopathological characteristics of this tumour, including T cell receptor (TCR) phenotype and the patients background, remain unknown. The aim of this study was to elucidate the detailed clinicopathological profile of EBV+ ITNKL.

Interaction of cytokeratin 19 head domain and HER2 in the cytoplasm leads to activation of HER2-Erk pathway

HER2 is a receptor tyrosine kinase and its upregulation via activating mutations or amplification has been identified in some malignant tumors, including lung cancers. Because HER2 can be a therapeutic target in HER2-driven malignancies, it is important to understand the molecular mechanisms of HER2 activation. In the current study, we identified that cytokeratin 19 (KRT19) binds to HER2 at the inside face of plasma membrane. HER2 and KRT19, which were concurrently introduced to a human embryonic kidney 293 T cells, revealed an association with each other and resulted in phosphorylation of HER2 with the subsequent activation of a downstream Erk-associated pathway. A binding assay revealed that both the NH2-terminal head domain of KRT19 and the COOH-terminal domain of HER2 were essential for their binding. To investigate the impact of the interaction between HER2 and KRT19 in lung cancer, we examined their expressions and localizations in lung cancers. We found that KRT19 was highly expressed in HER2-positive lung cancer cells, and KRT19 and HER2 were co-localized at the cell membrane. In conclusion, we found that KRT19 intracellularly binds to HER2, playing a critical role in HER2 activation.

Clinicopathological features of 49 primary gastrointestinal diffuse large B‐cell lymphoma cases; comparison with location, cell‐of‐origin, and frequency of MYD88 L265P

The gastrointestinal (GI) tract is the most common primary site of extranodal diffuse large B‐cell lymphoma (DLBCL), with approximately one‐third of extranodal DLBCL occurring in the GI tract. We investigated the clinicopathological features and immunohistochemically‐assessed cell‐of‐origin of 49 GI DLBCL cases (stomach, 24; small intestine, 10; colon, 15) and also examined the presence of MYD88 L265P as recently this mutation has been frequently identified in ABC‐like DLBCL, particularly in extranodal sites. Small intestinal DLBCL was characterized by the preponderance of women (P = 0.041) and elevated LDH (P = 0.002) and soluble interleukin‐2 receptor (P = 0.033). Small intestinal DLBCL more frequently showed anemia (P = 0.031) and elevated CRP (P = 0.029) than gastric DLBCL. ABC‐like phenotype was seen in 71.4 % cases (stomach, 79 %; small intestine, 70 %; colon, 60 %). MYD88 L265P was detected in 6.1 % cases; all were primary gastric DLBCL with ABC‐like phenotype but had no distinct clinicopathological features. In conclusion, GI DLBCL had different clinicopathological features according to the primary site especially in the small intestine. Also, MYD88 L265P had little involvement in GI DLBCL compared with other extranodal DLBCLs, suggesting that its pathogenesis might be different from that of organs with a high frequency of MYD88 L265P.

Clinicopathologic analysis of 6 lymphomatoid gastropathy cases: expanding the disease spectrum to CD4-CD8+ cases.

Lymphomatoid gastropathy, which was first reported in 2010, is a rare NK-cell proliferation of cyCD3+, CD4−, CD5−, CD8−, CD56+ phenotypes with unknown etiology. The diagnosis is challenging, as there is histopathologic similarity to malignant lymphoma. In the 2010 report on 10 cases, all lesions were located in the stomach, and all regressed without any therapy. In the present study, we analyzed 6 cases of lymphomatoid gastropathy by investigating the clinicopathologic, immunohistochemical, and molecular findings. Endoscopic and morphologic appearances of all cases were consistent with previous reports, but 2 cases showed previously unreported unique immunophenotypes of CD4−CD8+. Three of 6 patients underwent lower gastrointestinal examination (1 case underwent double-balloon endoscopic examination), but no patient had lesions in the lower gastrointestinal tract. No obvious difference of histology was found between the cases of CD4-CD8-typical phenotype and ones of CD4−CD8+ phenotype. Both cases had similar clinical behavior as the other 4 cases, implying that the spectrum of the disease is broader than initially thought. Careful clinical and endoscopic follow-up is required for the diagnosis of lymphomatoid gastropathy, and additional case studies and molecular studies are warranted to further investigate the pathophysiology of this peculiar benign mimic of lymphoma.

Clinicopathological analysis of primary central nervous system NK/T cell lymphoma: rare and localized aggressive tumour among extranasal NK/T cell tumours

The central nervous system (CNS) is a rare primary site of non‐Hodgkin lymphoma. Although direct invasion of nasal natural killer (NK)/T cell tumours into CNS is reported occasionally, primary CNS NK/T cell lymphoma is extremely rare, and the clinicopathological features of primary CNS NK/T cell lymphoma remain largely unknown.