The gastrointestinal (GI) tract is the most commonly involved site of extranodal follicular lymphoma (FL). GI‐FL shows very indolent clinical behavior and localized at GI tract without any ...progression or transformation compared to nodal FL. The most frequently involved site of the GI tract was the duodenum followed by the jejunum and ileum, and only 15% of FL arising in the second part of the duodenum were localized there without scattered very small daughter lesions in other GI tract examined by double‐balloon endoscopy. The typical macroscopic appearance of GI‐FL was multiple white nodules. Microscopically, neoplastic cells were small‐ to medium‐sized lymphoid cells and formed neoplastic follicles. Most of the cases (>95%) were histologically Grade 1 to 2 (low grade). Several pathological and molecular characteristics were seen in GI‐FL (especially duodenal FL) compared with nodal FL: immunoglobulin heavy chain deviation to VH4 and VH5; memory B‐cell immunophenotype; and molecular features shared by mucosa‐associated lymphoid tissue lymphoma. Considering the pathological and molecular uniqueness of this disease, GI‐FL should be separately managed from nodal FL.
Despite receiving rituximab‐combined chemotherapy, follicular lymphoma (FL) patients often suffer tumor recurrence and understand that the cause of relapse in FL would thus significantly ameliorate ...the tumor therapeutics. In the present study, we show that TRA‐1‐60‐expressing cells are a unique population in FL, converge to the conventional stem cell marker Oct3/4 and ALDH1‐positive population, and resist current B‐lymphoma agents. TRA‐1‐60 expression was observed in scattered lymphoma cells in FL tissues only as well as in resting B‐lymphocytes inside germinal centers. Retrospective comparison between recurrent and cognate primary tissues showed that the number of TRA‐1‐60‐positive cells from rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone (R‐CHOP)‐treated FL had increased relative to primary tissue, a finding corroborated by assays on different rituximab‐treated FL cell lines, FL‐18 and DOHH2, wherein TRA‐positive cell numbers increased over 10‐fold compared to the untreated sample. Concordantly, scanty TRA‐1‐60‐positive FL‐18 cells implanted s.c. into mice evinced potent tumor‐initiating capacity in vivo, where tumors were 12‐fold larger in volume (P = 0.0021 < 0.005) and 13‐fold heavier in weight (P = 0.0015 < 0.005) compared to those xenografted from TRA‐negative cells. To explain these results, gene expression profiling and qPCR analysis indicated that TRA‐1‐60‐positive cells defined a distinct population from that of TRA‐negative cells, with upregulation of multiple drug transporters and therapeutic resistance genes. Hence, TRA‐1‐60‐expressing cells in FL are considered to be vigorously intractable against conventional therapeutic agents, which may explain its refractory recurrence.
TRA‐1‐60 should be a prominent focus among cellular markers in follicular lymphoma research, by which we ultimately hope to explain clinical intractability against current rituximab‐combination and other therapies, and to better understand the unique population among a range of lymphoma cell types.
Nodal cytotoxic molecule (CM)‐positive peripheral T‐cell lymphoma (CTL) has recently been recognized as a clinicopathologically distinct disease. To further characterize this disease, here we ...compared 58 patients with Epstein‐Barr virus (EBV)‐negative CTL to 48 patients with EBV‐positive CTL. The two groups did not differ in histopathology, T‐cell receptor (TCR) expression or rearrangement incidences, or survival curves. However, patients with EBV‐negative CTL less frequently showed hepatic involvement (P = .007), B symptoms (P = .020), hemophagocytosis (P = .024), and detectable CD4 (P = .002) and CD5 (P = .009). Univariate and multivariate analyses identified three factors that independently predicted favorable survival, onset age <60 years (P = .002), CD5 expression (P = .002), and mixed morphology (P = .013), TCRαβ was not an independent predictor (P = .30), but was strongly linked with long survivorship among patients younger than 60 years old. A prognostic model incorporating these factors worked well for prognostic delineation, independently of the International Prognostic Index (P = .007 vs P = .082) and Prognostic Index for PTCL (P = .020 vs P = .15). Moreover, this constellation of findings indicated two nodal indolent diseases: CD5+TCRαβ (n = 13), and CD5+ NK‐cell type lacking TCR expression or clonal TCRγ rearrangement (n = 4). The survival curves for these two groups were significantly superior to others (n = 29, P < .001). These diseases appear to be unique in their indolent clinical behavior, and should be managed differently from other diseases.
This retrospective study revealed that nodal EBV‐negative CTL is heterogeneous, and there may be prognostically indolent subgroups defined by immunophenotype and genotype—ie, CD5+ TCRαβ and CD5+ NK‐cell types—which have not previously been highlighted.
High-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (HGBL-DH/TH) has a poor outcome after standard chemoimmunotherapy. We sought to understand the biologic underpinnings of ...HGBL-DH/TH with BCL2 rearrangements (HGBL-DH/TH- BCL2) and diffuse large B-cell lymphoma (DLBCL) morphology through examination of gene expression.
We analyzed RNA sequencing data from 157 de novo germinal center B-cell-like (GCB)-DLBCLs, including 25 with HGBL-DH/TH- BCL2, to define a gene expression signature that distinguishes HGBL-DH/TH- BCL2 from other GCB-DLBCLs. To assess the genetic, molecular, and phenotypic features associated with this signature, we analyzed targeted resequencing, whole-exome sequencing, RNA sequencing, and immunohistochemistry data.
We developed a 104-gene double-hit signature (DHITsig) that assigned 27% of GCB-DLBCLs to the DHITsig-positive group, with only one half harboring MYC and BCL2 rearrangements (HGBL-DH/TH- BCL2). DHITsig-positive patients had inferior outcomes after rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone immunochemotherapy compared with DHITsig-negative patients (5-year time to progression rate, 57% and 81%, respectively; P < .001), irrespective of HGBL-DH/TH- BCL2 status. The prognostic value of DHITsig was confirmed in an independent validation cohort. DHITsig-positive tumors are biologically characterized by a putative non-light zone germinal center cell of origin and a distinct mutational landscape that comprises genes associated with chromatin modification. A new NanoString assay (DLBCL90) recapitulated the prognostic significance and RNA sequencing assignments. Validating the association with HGBL-DH/TH- BCL2, 11 of 25 DHITsig-positive-transformed follicular lymphomas were classified as HGBL-DH/TH- BCL2 compared with zero of 50 in the DHITsig-negative group. Furthermore, the DHITsig was shared with the majority of B-cell lymphomas with high-grade morphology tested.
We have defined a clinically and biologically distinct subgroup of tumors within GCB-DLBCL characterized by a gene expression signature of HGBL-DH/TH- BCL2. This knowledge has been translated into an assay applicable to routinely available biopsy samples, which enables exploration of its utility to guide patient management.
Aims
Although the neoplastic cells of extranodal natural killer (NK)/T‐cell lymphoma (ENKTL) usually do not express T‐cell antigens, the T‐cell receptor (TCR) gene might be rearranged and TCR protein ...expressed. The aim is to elucidate the expression of the downstream TCR pathway components and their importance in ENKTL.
Methods and results
We used formalin‐fixed paraffin‐embedded tissues from 91 ENKTL samples to immunohistochemically characterise the expression of TCR pathway components. The following proteins were variably expressed: ZAP70 (94%; 83/88), GRAP2/GADS (68%; 60/88), DOK2 (42%; 38/90), LCK (35%; 31/88), and ITK (10%; 9/90). When these tumours were classified as being of T lineage (16%), NK lineage (45%), or indeterminate lineage (38%), the GRAP2/GADS expression rate was higher in T lineage tumours (versus NK, P = 0.0073; versus indeterminate, P = 0.00082). GRAP2/GADS‐positive NK lineage tumours more frequently expressed DOK2 (P = 0.0073), and were more often confined to the nasal areas (P = 0.014). Furthermore, when these tumours were immunophenotypically classified into a T signature (42%) or NK signature (58%), the expression rates of GRAP2/GADS and ITK were higher in T signature tumours (P = 0.00074 and P = 0.067, respectively), whereas that of LCK was higher in NK‐signature tumours (P = 0.10).
Conclusions
Although some ENTKL cases were polyclonal for TCR rearrangement and others lacked TCR expression, we speculate that the TCR pathway might be functioning in ENKTLs. A T signature versus a NK signature might be better for delineating the physiology of ENKTL than cellular lineage. Furthermore, ITK may represent a potential therapeutic target for patients with ITK‐expressing tumours.
Follicular lymphoma (FL) shows co‐expression of B‐cell lymphoma 2 (BCL2) and CD10, whereas downexpression of CD10 is occasionally experienced in gastrointestinal (GI) FL with unknown significance. ...Gastrointestinal FL is a rare variant of FL, and its similarity with mucosa‐associated lymphoid tissue lymphoma was reported. We investigated the clinicopathological and genetic features of CD10 downexpressed (CD10down) GI‐FL. The diagnosis of CD10down FL was carried out with a combination of pathological and molecular analyses. The incidence of CD10down GI‐FL was shown in 35/172 (20.3%) cases, which was more frequent than nodal FL (3.5%, P < 0.001). The difference was additionally significant between GI‐FL and nodal FL when the analysis was confined to primary GI‐FL (55.2% vs 3.5%, P < 0.001). Compared to CD10+ GI‐FL, CD10down GI‐FL significantly involved the stomach or large intestine (P = 0.015), and additionally showed the downexpression of BCL6 (P < 0.001). The follicular dendritic cell meshwork often showed a duodenal pattern in the CD10down group (P = 0.12). Furthermore, a lymphoepithelial lesion was observed in 5/12 (40%) gastric FL cases, which indicated caution in the differentiation of mucosa‐associated lymphoid tissue lymphoma. Molecular analyses were undertaken in seven cases of CD10down GI‐FL, and an identical clone was found between CD10down follicles and CD10+BCL2+ neoplastic follicles. In the diagnosis of cases with CD10down BCL2+ follicles, careful examination with molecular studies should be carried out.
Identical clone was detected between CD10‐down expressed follicle and CD10+BCL2+ follicle.
Myeloid sarcoma (MS) is a condition characterized by a tumor mass of myeloid blasts in any site of the body other than the bone marrow, with or without acute myeloid leukemia. A 93-year-old man ...underwent laparoscopy-assisted distal gastrectomy with D1 lymphadenectomy for advanced gastric cancer. Other than metastatic foci of gastric cancer cells, some dissected lymph nodes showed destructive architecture with proliferation of small- to medium-sized atypical hematopoietic cells. Those cells were focally positive for naphthol AS-D chloroacetate esterase. Immunohistochemically, positive results were obtained for CD4, CD33, CD68 (KP1), Iba-1, lysozyme, myeloperoxidase, and PU.1, with focally positive results for CD13, CD14, CD68 (PGM1), CD163, and CD204, and negative results for AE1/AE3, CD1a, CD3, CD20, and S-100 protein. These results suggested MS with phenotypically myelomonocytic differentiation. We report a rare case of MS incidentally found in specimens resected for other purposes. Careful diagnosis and consideration of differential diagnoses including MS using an adequate panel of antibody markers for dissected lymph nodes is warranted.
In the new WHO classifications of haematolymphoid tumours (WHO-HAEM5), classic Hodgkin lymphoma (cHL) is categorized into B-cell lymphoid proliferations and lymphomas. Although the majority of ...Hodgkin Reed-Sternberg (HRS) cells are of germinal center B-cell origin with some defects of B-cell transcription factors, they rarely express T-cell antigens or cytotoxic molecules. Clonality analyses on cHL samples using BIOMED-2 have been reported by several groups; however, those studies were only focused on Ig regions, including IgH, Ig-kappa, and Ig-lambda, and TCR-γ clonality analysis of cHL has not yet been explored. Here, we investigated TCR-γ gene rearrangement for one hundred cases using a PCR-based method. Four of one hundred (4%) cases showed TCR-γ clonal peaks. Of these, three were at an advanced stage and one patient died of the disease. To clarify whether HRS cells showed T-cell clonality or not, we performed PCR analysis using DNAs of microdissected HRS cells. Three samples showed identical clonal peaks with bulk specimens. Our results indicate that cHL is a heterogeneous disease of mainly B-cell and rarely T-cell origin with a special phenotype. Further molecular studies are warranted.
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.
Diffuse large B‐cell lymphoma (DLBCL) is the most common B‐cell lymphoma subtype, and the Epstein–Barr virus (EBV)‐positive subtype of DLBCL is known to show a more aggressive clinical behavior than ...the EBV‐negative one. BTB and CNC homology 2 (BACH2) has been highlighted as a tumor suppressor in hematopoietic malignancies; however, the role of BACH2 in EBV‐positive DLBCL is unclear. In the present study, BACH2 expression and its significance were studied in 23 EBV‐positive and 43 EBV‐negative patient samples. Immunohistochemistry revealed BACH2 downregulation in EBV‐positive cases (P < 0.0001), although biallelic deletion of BACH2 was not detected by FISH. Next, we analyzed the contribution of BACH2 negativity to aggressiveness in EBV‐positive B‐cell lymphomas using FL‐18 (EBV‐negative) and FL‐18‐EB cells (FL‐18 sister cell line, EBV‐positive). In BACH2‐transfected FL‐18‐EB cells, downregulation of phosphorylated transforming growth factor‐β‐activated kinase 1 (pTAK1) and suppression in p65 nuclear fractions were observed by Western blot analysis contrary to non‐transfected FL‐18‐EB cells. In patient samples, pTAK1 expression and significant nuclear p65, p50, and p52 localization were detected immunohistochemically in BACH2‐negative DLBCL (P < 0.0001, P = 0.006, and P = 0.001, respectively), suggesting that BACH2 downregulation contributes to constitutive activation of the nuclear factor‐κB pathway through TAK1 phosphorylation in BACH2‐negative DLBCL (most EBV‐positive cases). Although further molecular and pathological studies are warranted to clarify the detailed mechanisms, downregulation of BACH2 may contribute to constitutive activation of the nuclear factor‐κB pathway through TAK1 activation.
BACH2 expression was downregulated in the majority of EBV‐positive DLBCL cases, and indicated it contributes to constitutive activation of the NFkB pathway in an EBV‐positive B‐cell lymphoma cells.