In the early 1980s, the first human retrovirus, human T‐cell leukemia virus type I (HTLV‐I), was isolated and its characterization opened up the new field of human viral oncology. Adult T‐cell ...leukemia/lymphoma (ATLL), which is associated with HTLV‐I, is characterized clinically by the appearance of characteristic flower cells, a rapid clinical course, occasional skin lesions, lymphadenopathy and hepatosplenomegaly. Severe opportunistic infections are occasionally accompanied. In addition, HTLV‐I infection is associated with autoimmune and reactive disorders, such as HTLV‐I‐associated myelopathy and uveitis, and is also related to immunodeficient infectious diseases. Pathological findings of ATLL in the lymph nodes, skin, liver and other organs have been described. Common histological features are a diffuse proliferation of atypical lymphoid cells that vary in size and shape. In addition to ATLL, non‐neoplastic organopathies have been documented in many organs, such as the central nerve system, lung, skin, lymph nodes and gastrointestinal tract. To clarify the HTLV‐I‐associated diseases, it is important to understand the pathological variations. (Cancer Sci 2007; 98: 772–778)
The morbidity and mortality of disease vary according to the region and may also change over time. The morbidity and mortality of malignant lymphoma are also affected by differences in ethnicity, ...lifestyle habits, geographical area, and time period. Increasing research on malignant lymphoma has focused on its pathophysiology, diagnosis, and therapeutic treatment. Recent improvements in the accuracy of clinical study, technologies such as next-generation sequencing, and the development of targeted molecular agents have also resulted in a number of excellent studies. This review summarizes the epidemiology of malignant lymphoma and highlights novel studies on adult T-cell leukemia/lymphoma recently published in Japan.
Peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) is a diagnosis of exclusion, being the most common entity in mature T-cell neoplasms, and its molecular pathogenesis remains ...significantly understudied. Here, combining whole-exome and targeted-capture sequencing, gene-expression profiling, and immunohistochemical analysis of tumor samples from 133 cases, we have delineated the entire landscape of somatic alterations, and discovered frequently affected driver pathways in PTCL, NOS, with and without a T-follicular helper (TFH) cell phenotype. In addition to previously reported mutational targets, we identified a number of novel recurrently altered genes, such as KMT2C, SETD1B, YTHDF2, and PDCD1. We integrated these genetic drivers using hierarchical clustering and identified a previously undescribed molecular subtype characterized by TP53 and/or CDKN2A mutations and deletions in non-TFH PTCL, NOS. This subtype exhibited different prognosis and unique genetic features associated with extensive chromosomal instability, which preferentially affected molecules involved in immune escape and transcriptional regulation, such as HLA-A/B and IKZF2. Taken together, our findings provide novel insights into the molecular pathogenesis of PTCL, NOS by highlighting their genetic heterogeneity. These results should help to devise a novel molecular classification of PTCLs and to exploit a new therapeutic strategy for this group of aggressive malignancies.
Myeloid sarcoma (MS) is an extramedullary tumor of immature myeloid cells. We analyzed 131 patients with MS, including: (1) de novo MS; (2) MS with concomitant acute myeloid leukemia (AML); (3) MS ...following myelodysplastic syndrome, myeloproliferative neoplasm, or chronic myelogenous leukemia; and (4) MS as a recurrence of AML. The most common development site was the lymph node. Testicular lesions were statistically more frequent in MS as a recurrence of AML than in other types of MS (P=0.0183). MS tended to lack myeloid markers (myeloperoxidase was present in 63.2%, CD68 in 51.3%, CD13 in 48.7%, and CD33 in 48.7% of patients) and express T-cell markers such as CD3 (20.7%) and CD5 (34.2%). All T-cell marker-positive MS cases were negative for the αβ and γδ T-cell receptors on immunohistochemistry. Underlying myelodysplastic syndrome or myeloproliferative neoplasm was a poor prognostic factor (vs. de novo MS: P=0.0383; vs. MS with concomitant AML: P=0.0143). However, there was no statistical difference in prognosis between de novo MS and MS with concomitant AML (P=0.288). There were no significant differences in prognosis between the prognoses of T-cell marker-positive and T-cell marker-negative MS cases. In addition, CXCR4 expression was a poor prognostic factor in MS (P=0.0229). This study involves the largest MS cohort to date and expands the clinical and pathologic knowledge of the disease.
A pathological evaluation is one of the most important methods for the diagnosis of malignant lymphoma. A standardized diagnosis is occasionally difficult to achieve even by experienced ...hematopathologists. Therefore, established procedures including a computer-aided diagnosis are desired. This study aims to classify histopathological images of malignant lymphomas through deep learning, which is a computer algorithm and type of artificial intelligence (AI) technology. We prepared hematoxylin and eosin (H&E) slides of a lesion area from 388 sections, namely, 259 with diffuse large B-cell lymphoma, 89 with follicular lymphoma, and 40 with reactive lymphoid hyperplasia, and created whole slide images (WSIs) using a whole slide system. WSI was annotated in the lesion area by experienced hematopathologists. Image patches were cropped from the WSI to train and evaluate the classifiers. Image patches at magnifications of ×5, ×20, and ×40 were randomly divided into a test set and a training and evaluation set. The classifier was assessed using the test set through a cross-validation after training. The classifier achieved the highest levels of accuracy of 94.0%, 93.0%, and 92.0% for image patches with magnifications of ×5, ×20, and ×40, respectively, in comparison to diffuse large B-cell lymphoma, follicular lymphoma, and reactive lymphoid hyperplasia. Comparing the diagnostic accuracies between the proposed classifier and seven pathologists, including experienced hematopathologists, using the test set made up of image patches with magnifications of ×5, ×20, and ×40, the best accuracy demonstrated by the classifier was 97.0%, whereas the average accuracy achieved by the pathologists using WSIs was 76.0%, with the highest accuracy reaching 83.3%. In conclusion, the neural classifier can outperform pathologists in a morphological evaluation. These results suggest that the AI system can potentially support the diagnosis of malignant lymphoma.
This study aims to classify histopathological images of malignant lymphoma through deep learning. The classifier achieved the high levels of accuracy in comparison to diffuse large B-cell lymphoma, follicular lymphoma, and reactive lymphoid hyperplasia, which were higher than those of pathologists. Artificial intelligence can potentially support diagnosis of malignant lymphoma.
Peripheral T‐cell lymphoma (PTCL) is a heterogeneous entity generally with a poor prognosis. Recent genomic analyses have characterized genomic alterations and described gene expression profiling and ...epigenetic mechanisms in PTCL, leading to reveal molecular pathophysiology in detail. One of several important findings is that heterogeneities exist in both the disease and in individuals. Among PTCL subtypes, adult T‐cell leukemia/lymphoma (ATLL) and peripheral T‐cell lymphoma, not otherwise specified (PTCL‐NOS) are common in Japan. ATLL is an incurable T‐cell malignancy induced by human T‐cell lymphotropic virus type 1 (HTLV‐1). The global genomics of ATLL can be summarized as alterations involving T‐cell receptor (TCR) signaling and immune escape mechanisms. This highlights the fact that ATLL is a viral‐mediated T‐cell malignancy. Interestingly, several previous studies have found that the genomics of ATLL differ according to geographical region and age at diagnosis, suggesting disease heterogeneity, though they share HTLV‐1 infection as initial disease hit. Clonal expansion of the cells acquired by somatic mutations in ATLL‐related genes is identified in a part of HTLV‐1 carriers who developed ATLL later. The risk for ATLL may be updated based on findings in detail. PTCL‐NOS is a heterogeneous disease type of T‐cell lymphoma that does not correspond to any other type of PTCL. Several studies have stratified PTCL‐NOS according to transcriptional, genomic, microenvironmental, and clinical aspects. These kinds of analysis from multiple aspects are useful to understand the heterogeneous group. These efforts will help guide suitable translational research to target PTCL.
Coexistence of CD28 fusions is highly characteristic of young Japanese adult T‐cell leukemia/lymphoma (ATLL). This suggests the existence of heterogeneity of ATLL.
The tumor microenvironment consists of many non‐tumor cells such as leukocytes, endothelial cells, and fibroblasts, and phenotypic changes in a tumor microenvironment are believed to be involved in ...tumor progression and resistance to anticancer treatments. In hematological malignancies, tumor‐associated macrophages (TAMs) that have infiltrated lymphoma or leukemia tissues may be involved in tumor progression, and many researchers have studied phenotypic changes in TAMs. This review article summarizes the publications related to TAMs in hematological malignancies, with an emphasis on CD163+ protumoral TAMs, which seem to be associated with disease progression. Cell‐cell interactions between protumoral TAMs and lymphoma or leukemia cells may play an important role in lymphoma or leukemia microenvironments. Although detailed molecular mechanisms of these cell‐cell interactions have not yet been clarified, phenotypic characterization of TAMs is thought to be a useful approach for evaluating clinical prognosis. In addition, targeting TAMs may be a new strategy for treating malignant hematological diseases.
Transforming acidic coiled‐coil‐containing protein 3 (TACC3) plays an important role in centrosome/microtubule dynamics. Deregulation of centrosomes/microtubules causes mitotic spindle defects, ...leading to tumorigenesis. However, the correlation between TACC3 and primary central nervous system lymphomas (PCNSLs) is unknown. The present study investigated the association between the immunohistochemical expression of TACC3, p53, and Ki‐67, and the clinical factors in 40 PCNSLs. We evaluated the staining of TACC3 based on the histoscore (H‐score) that contains a semiquantitative evaluation of both the intensity of staining, and the percentage of positive cells. Expression level of each component was classified as low or high according to the median H‐score value. Patients with PCNSLs were divided into groups depending on TACC3 expression levels (no expression and low expression, 18; high expression, 22). Disease‐free survival and overall survival of patients with high TACC3 expression were significantly shorter (p < 0.01 and p < 0.05, respectively). These results suggest that elevated expression of TACC3 could reflects aggressiveness of primary central nervous system lymphomas.
The activities of non-haematopoietic cells (NHCs), including mesenchymal stromal cells and endothelial cells, in lymphomas are reported to underlie lymphomagenesis. However, our understanding of ...lymphoma NHCs has been hampered by unexplained NHC heterogeneity, even in normal human lymph nodes (LNs). Here we constructed a single-cell transcriptome atlas of more than 100,000 NHCs collected from 27 human samples, including LNs and various nodal lymphomas, and it revealed 30 distinct subclusters, including some that were previously unrecognized. Notably, this atlas was useful for comparative analyses with lymphoma NHCs, which revealed an unanticipated landscape of subcluster-specific changes in gene expression and interaction with malignant cells in follicular lymphoma NHCs. This facilitates our understanding of stromal remodelling in lymphoma and highlights potential clinical biomarkers. Our study largely updates NHC taxonomy in human LNs and analysis of disease status, and provides a rich resource and deeper insights into LN and lymphoma biology to advance lymphoma management and therapy.
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