Yasuo Sugita

Expression of programmed cell death ligand 1 is associated with poor overall survival in patients with diffuse large B-cell lymphoma

Programmed cell death ligand 1 (PD-L1) is expressed on both select diffuse large B-cell lymphoma (DLBCL) tumor cells and on tumor-infiltrating nonmalignant cells. The programmed cell death 1 (PD-1)/PD-L1 pathway inhibits host antitumor responses; however, little is known about how this pathway functions in the tumor microenvironment. The aim of this study was to determine the clinicopathological impact of PD-L1(+) DLBCL. We performed PD-L1/PAX5 double immunostaining in 1253 DLBCL biopsy samples and established a new definition of PD-L1(+) DLBCL. We also defined the criteria for microenvironmental PD-L1(+) (mPD-L1(+)) DLBCL (ie, PD-L1(-) DLBCL in which PD-L1(+) nonmalignant cells are abundant in the tumor microenvironment). Of the 273 patients whose clinical information was available, quantitative analysis of PD-1(+) tumor-infiltrating lymphocytes (TILs) was performed. The prevalence rates of PD-L1(+) and mPD-L1(+) DLBCL were 11% and 15.3%, respectively. Both PD-L1(+) and mPD-L1(+) DLBCL were significantly associated with non-germinal center B-cell (GCB) type and Epstein-Barr virus positivity. The number of PD-1(+) TILs was significantly higher in GCB-type tumors and lower in mPD-L1(-) and PD-L1(+) DLBCL. Patients with PD-L1(+) DLBCL had inferior overall survival (OS) compared with that in patients with PD-L1(-) DLBCL (P = .0009). In contrast, there was no significant difference in OS between mPD-L1(+) and mPD-L1(-) DLBCL (P = .31). The expression of PD-L1 maintained prognostic value for OS in multivariate analysis (P = .0323). This is the first report describing the clinicopathological features and outcomes of PD-L1(+) DLBCL. Immunotherapy targeting the PD-1/PD-L1 pathway should be considered in this distinct DLBCL subgroup.

Methotrexate/iatrogenic lymphoproliferative disorders in rheumatoid arthritis: histology, Epstein–Barr virus, and clonality are important predictors of disease progression and regression

Patients with rheumatoid arthritis (RA) may develop lymphoproliferative disorders (RA‐LPD). Immunosuppressive states due to methotrexate (MTX) and Epstein–Barr virus (EBV) reactivation have been regarded as causes. Sometimes spontaneous regression occurs after withdrawal of MTX. The objective of this study was to identify factors predictive of relapse and survival in patients with RA‐LPD, and spontaneous regression in patients with RA‐LPD treated with MTX (MTX‐LPD).

Ratio of M2 macrophage expression is closely associated with poor prognosis for Angioimmunoblastic T-cell lymphoma (AITL)

Angioimmunoblastic T‐cell lymphoma (AITL) is a peripheral T‐cell lymphoma characterized by systemic disease with polymorphous infiltrate including macrophages. Although many studies of tumor‐associated macrophage (TAM) populations in various malignant tumors have been published, only a few have dealt with activation of macrophage phenotypes such as M1 and M2 in tumor tissue. Because M2 macrophages highly express CD163, we suspected that CD163 may be a useful marker for identification of activation of macrophage phenotypes in AITL. We performed a retrospective study of immunohistochemical expression using two markers for macrophages [CD68 (PG‐M1), CD163] and of the correlation of these expressions with overall survival of 42 AITL patients. The number of CD68‐positive cells in AITL tissues did not correlate with overall survival (P= 0.59), whereas the number of CD163‐positive cells and overall survival correlated to some extent (P= 0.08). Meanwhile, a higher ratio of CD163‐positive to CD68‐positive cells in AITL significantly correlated with worse overall survival (P= 0.036). Considering that this ratio reflects the proportion of macrophages polarized to the M2 phenotype, our findings indicate that activation of macrophages towards the M2 phenotype correlates with worse prognosis. Our findings indicate that the ratio of M2 macrophages expressed may be a useful marker for prognosis of AITL.

Distribution of malignant lymphoma in Japan: Analysis of 2260 cases, 2001–2006

The World Health Organization classification was used to conduct an analysis of geographic, age, sex, and lesion primarily biopsied/resected distribution of 2260 lymphoid neoplasms diagnosed during 2001–2006 throughout Japan. B‐cell neoplasms accounted for 65% of all lymphoid neoplasms, T/natural killer (T/NK)‐cell neoplasms for 25% and Hodgkin lymphoma for 7%. The most common type was diffuse large B‐cell lymphoma (DLBCL, 33%), followed by follicular lymphoma (18%), and adult T‐cell leukemia/lymphoma (ATLL, 10%). The high rate of 18% for follicular lymphoma was similar to that in Western countries (11–33%). T/NK‐cell neoplasms accounted for a higher percentage of lymphoid neoplasms in Kyushu (30%) and Okinawa (38%) compared with other areas of Japan (18–20%). Among T/NK‐cell neoplasms, ATLL was the most common type in Okinawa (54%) and Kyushu (59%). Extranodal NK/T cell lymphoma was the second most common type of T/NK‐cell neoplasms in Okinawa (15%). This epidemiological study shows that the distribution patterns of malignant lymphoma differ especially in Kyushu and Okinawa, the endemic area of human T‐cell leukemia/lymphoma virus type 1.

Usefulness of flow cytometry for differential diagnosis of precursor and peripheral T-cell and NK-cell lymphomas: analysis of 490 cases.

Although various CD markers have been analyzed in T‐cell and natural killer (NK)‐cell lymphomas, the sensitivity and specificity of these phenotypic features have not been satisfactorily characterized. Flow cytometry (FCM) was used to determine the phenotypic pattern of 490 T/NK‐cell lymphomas with the aid of a set of surface antigens (CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD11c, CD16, CD19, CD20, CD25, CD30, CD34, and CD56). In data obtained from 319 patients, CD10 expression was detected in 57% of angioimmunoblastic T‐cell lymphomas, CD30 in 93% of anaplastic large cell lymphomas, CD34 in 50% of lymphoblastic lymphomas, and CD56 in 100% of extranodal NK/T‐cell lymphomas nasal type. A total of 92% of adult T‐cell leukemia/lymphomas (ATLL) had expression of CD25 and downregulation of CD7. Of special interest is that 92 ATLL (50%) were CD4+CD7‐CD25+ phenotype while only four peripheral T‐cell lymphoma unspecified (9%) and one (9%) cutaneous T‐cell lymphoma had this phenotype. Phenotypic analysis using FCM was thus found to be useful for differential diagnosis of T‐cell and NK‐cell lymphomas.

YB-1 Bridges Neural Stem Cells and Brain Tumor–Initiating Cells via Its Roles in Differentiation and Cell Growth

The Y-box binding protein 1 (YB-1) is upregulated in many human malignancies including glioblastoma (GBM). It is also essential for normal brain development, suggesting that YB-1 is part of a neural stem cell (NSC) network. Here, we show that YB-1 was highly expressed in the subventricular zone (SVZ) of mouse fetal brain tissues but not in terminally differentiated primary astrocytes. Conversely, YB-1 knockout mice had reduced Sox-2, nestin, and musashi-1 expression in the SVZ. Although primary murine neurospheres were rich in YB-1, its expression was lost during glial differentiation. Glial tumors often express NSC markers and tend to loose the cellular control that governs differentiation; therefore, we addressed whether YB-1 served a similar role in cancer cells. YB-1, Sox-2, musashi-1, Bmi-1, and nestin are coordinately expressed in SF188 cells and 9/9 GBM patient-derived primary brain tumor-initiating cells (BTIC). Silencing YB-1 with siRNA attenuated the expression of these NSC markers, reduced neurosphere growth, and triggered differentiation via coordinate loss of GSK3-β. Furthermore, differentiation of BTIC with 1% serum or bone morphogenetic protein-4 suppressed YB-1 protein expression. Likewise, YB-1 expression was lost during differentiation of normal human NSCs. Consistent with these observations, YB-1 expression increased with tumor grade (n = 49 cases). YB-1 was also coexpressed with Bmi-1 (Spearmans 0.80, P > 0.001) and Sox-2 (Spearmans 0.66, P > 0.001) based on the analysis of 282 cases of high-grade gliomas. These proteins were highly expressed in 10/15 (67%) of GBM patients that subsequently relapsed. In conclusion, YB-1 correlatively expresses with NSC markers where it functions to promote cell growth and inhibit differentiation.

Gene expression analysis of rheumatoid arthritis synovial lining regions by cDNA microarray combined with laser microdissection: up-regulation of inflammation-associated STAT1, IRF1, CXCL9, CXCL10, and CCL5.

Objectives: The main histological change in rheumatoid arthritis (RA) is the villous proliferation of synovial lining cells, an important source of cytokines and chemokines, which are associated with inflammation. The aim of this study was to evaluate gene expression in the microdissected synovial lining cells of RA patients, using those of osteoarthritis (OA) patients as the control. Methods: Samples were obtained during total joint replacement from 11 RA and five OA patients. Total RNA from the synovial lining cells was derived from selected specimens by laser microdissection (LMD) for subsequent cDNA microarray analysis. In addition, the expression of significant genes was confirmed immunohistochemically. Results: The 14 519 genes detected by cDNA microarray were used to compare gene expression levels in synovial lining cells from RA with those from OA patients. Cluster analysis indicated that RA cells, including low- and high-expression subgroups, and OA cells were stored in two main clusters. The molecular activity of RA was statistically consistent with its clinical and histological activity. Expression levels of signal transducer and activator of transcription 1 (STAT1), interferon regulatory factor 1 (IRF1), and the chemokines CXCL9, CXCL10, and CCL5 were statistically significantly higher in the synovium of RA than in that of OA. Immunohistochemically, the lining synovium of RA, but not that of OA, clearly expressed STAT1, IRF1, and chemokines, as was seen in microarray analysis combined with LMD. Conclusions: Our findings indicate an important role for lining synovial cells in the inflammatory and proliferative processes of RA. Further understanding of the local signalling in structural components is important in rheumatology.

CXCL12/CXCR4 signaling in malignant brain tumors: a potential pharmacological therapeutic target

Chemokines are 8- to 12-kDa peptides that function as chemoattractant cytokines involved in cell activation, differentiation, and trafficking. Chemokines bind to specific G-protein-coupled, seven-span transmembrane receptors on the plasma membrane of target cells. Chemokine (C-X-C motif) ligand 12 (CXCL12), an alpha-chemokine that binds to G-protein-coupled chemokine (C-X-C motif) receptor 4 (CXCR4), plays an important and unique role in the regulation of stem/progenitor-cell trafficking. As CXCR4 is expressed on several cancer cells, these CXCR4-positive cancer cells may metastasize to organs that secrete/express CXCL12. Regarding brain tumors, recent data demonstrate that glioma tumor stem-like cells promote tumor angiogenesis and vasculogenesis via the CXCL12/CXCR4 pathway. In addition, CXCL12/CXCR4 have recently been shown to be expressed in primary central nervous system (PCNS) lymphomas, and a role for chemokines in the pathogenesis of PCNS lymphomas was suggested. This review focuses on current knowledge regarding the biology of the CXCL12/CXCR4 pathway in the context of understanding their potential role in malignant gliomas and PCNS lymphoma development. The CXCL12/CXCR4 interaction as a therapeutic target for malignant brain tumors is also discussed.

The relationship of FOXP3 expression and clinicopathological characteristics in adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma is an aggressive malignant disease associated with regulatory T cells as discussed in some recent reports. We analyzed the expression of FOXP3, a key molecule of regulatory T cells, in adult T-cell leukemia/lymphoma and its association with clinicopathological features. Of 169 adult T-cell leukemia/lymphoma cases examined, 60 (36%) showed FOXP3 expression in lymphoma cells. Morphologically, 22 cases were classified as anaplastic large cell variant and 147 as pleomorphic cell variant. Only 1 (5%) of the anaplastic large cell variant cases and 59/147 (40%) of the pleomorphic cell variant cases expressed FOXP3. Epstein–Barr virus-infected cells were significantly more frequently found in FOXP3(+) cases (23/60; 38%) than in FOXP3(−) cases (12/109; 11%) (P<0.0001). Cytogenetic analysis showed that FOXP3(+) cases had simpler chromosomal abnormalities than FOXP3(−) cases. Clinically, FOXP3(+) and FOXP3(−) cases did not differ significantly in age distribution, clinical stage, lactate dehydrogenase and calcium in serum and overall survival. However, 8 of 34 FOXP3(+) cases suffered a severe infectious state, an indication of immunosuppression, while only 2 of 62 FOXP3(−) cases did so (P<0.005). FOXP3 expression in adult T-cell leukemia/lymphoma thus reflects morphological features and is clinically and pathologically associated with an immunosuppressive state.

Acute focal demyelinating disease simulating brain tumors: histopathologic guidelines for an accurate diagnosis.

The object of the present study was to determine the histopathological guidelines for accurate diagnosis of cases of acute focal demyelinating disease that simulates brain tumors. The surgical pathology of three such cases is assessed. Histopathological keys to the diagnosis of such cases are as follows. First, a pattern of sheets of atypical gemistocytic astrocytes in the white matter that show well‐formed processes and that are adequately distanced from each other argues against a diagnosis of neoplasm. Second, uniform distribution of foamy macrophages aligned along axons, with occasional focal collections surrounding blood vessels and in the absence of any associated coagulative necrosis argues against the presence of a tumor. Third, perivascular chronic inflammatory infiltration, especially a mixture of lymphocytes and macrophages, favors the diagnosis of demyelination plaque. In such cases the lymphocytes will be predominantly T cells. Fourth, pleomorphic astrocytic proliferation with a lack of vascular endothelial proliferation should raise the suspicion that the lesion may not be a brain tumor. These diagnostic keys should be followed when diagnosing cases that are suspected to be demyelination processes rather than brain tumors. The presence of demyelination plaque should then be confirmed by imaging modalities such as staining with myelin‐and axon‐specific stains.