Liver biopsy in the post-hepatitis C virus era in Japan.

In Japan, liver biopsies were previously crucial in evaluating the severity of hepatitis caused by the hepatitis C virus (HCV) and diagnosing HCV-related hepatocellular carcinoma (HCC). However, due to the development of effective antiviral treatments and advanced imaging, the necessity for biopsies has significantly decreased. This change has resulted in fewer chances for diagnosing liver disease, causing many general pathologists to feel less confident in making liver biopsy diagnoses. This article provides a comprehensive overview of the challenges and potential solutions related to liver biopsies in Japan. First, it highlights the importance of considering steatotic liver diseases as independent conditions that can coexist with other liver diseases due to their increasing prevalence. Second, it emphasizes the need to avoid hasty assumptions of HCC in nodular lesions, because clinically diagnosable HCCs are not targets for biopsy. Third, the importance of diagnosing hepatic immune-related adverse events caused by immune checkpoint inhibitors is increasing due to the anticipated widespread use of these drugs. In conclusion, pathologists should be attuned to the changing landscape of liver diseases and approach liver biopsies with care and attention to detail.

Carcinogenesis caused by transcription-coupled DNA damage through GANP and other components of the TREX-2 complex.

Perturbation of genes is important for somatic hypermutation to increase antibody affinity during B-cell immunity; however, it may also promote carcinogenesis. Previous studies have revealed that transcription is an important process that can induce DNA damage and genomic instability. Transciption-export-2 (TREX-2) complex, which regulates messenger RNA (mRNA) nuclear export, has been studied in the budding yeast Saccharomyces cerevisiae; however, recent studies have started investigating the molecular function of the mammalian TREX-2 complex. The central molecule in the TREX-2 complex, that is, germinal center-associated nuclear protein (GANP), is closely associated with antibody affinity maturation as well as cancer etiology. In this review, we focus on carcinogenesis, lymphomagenesis, and teratomagenesis caused by transcription-coupled DNA damage through GANP and other components of the TREX-2 complex. We review the basic machinery of mRNA nuclear export and transcription-coupled DNA damage. We then briefly describe the immunological relationship between GANP and the affinity maturation of antibodies. Finally, we illustrate that the aberrant expression of the components of the TREX-2 complex, especially GANP, is associated with the etiology of various solid tumors, lymphomas, and testicular teratoma. These components serve as reliable predictors of cancer prognosis and response to chemotherapy.

Chromogenic in situ hybridization reveals specific expression pattern of long non-coding RNA DRAIC in formalin-fixed paraffin-embedded specimen.

Long non-coding RNA (lncRNA) plays an important role in the regulation of gene expression in normal and cancer cells. We previously discovered a novel tumor-suppressive lncRNA, DRAIC, in prostate cancer cells. Subsequent studies have demonstrated that DRAIC is dysregulated in various malignancies and exhibits a tumor-suppressive or pro-oncogenic function. However, details regarding its expression pattern in normal and cancerous tissues remain largely unknown. In this study, we performed chromogenic in situ hybridization (CISH) using RNAscope technology to assess DRAIC expression in formalin-fixed paraffin-embedded (FFPE) specimens. In the neuroendocrine-differentiated cancer cell line VMRC-LCD, CISH revealed a diffuse localization of DRAIC in the cytoplasm as well as specific accumulation in the nuclear compartment. DRAIC expression was comprehensively analyzed using tissue microarrays containing 89 normal and 155 tumor tissue samples. DRAIC was weakly expressed in normal epithelial cells of the colon, bronchiole, kidney, prostate, and testis. Conversely, DRAIC was moderately to highly expressed in some cancer tissues, including prostate adenocarcinoma, invasive ductal carcinoma of the breast, neuroendocrine carcinoma of the esophagus, lung adenocarcinoma, and small cell lung carcinoma. While DRAIC knockdown did not affect VMRC-LCD cellular viability and invasive ability, gene expression related to the neuroendocrine and cancer-related pathways was altered. Our expression analysis revealed the specific expression pattern of DRAIC in normal and cancerous FFPE tissues. The results presented here may lead to the elucidation of additional novel functions of DRAIC.

H19 in Serum Extracellular Vesicles Reflects Resistance to AR Axis-targeted Therapy Among CRPC Patients.

BACKGROUND/AIM: We aimed to evaluate the changes of androgen receptor (AR) signaling-related long non-coding RNAs (lncRNAs) in serum extracellular vesicles (EVs) from prostate cancer (PC) patients, in order to identify novel biomarkers for AR axis-targeted therapy (ARAT)-resistance among castration-resistant PC (CRPC) patients. PATIENTS AND METHODS: EVs were isolated from 2 patients before and after acquiring ARAT-resistance. RNA profiling of EVs was performed by RNA-sequencing. The expression levels of selected lncRNAs in EVs were analyzed by digital droplet PCR (ddPCR) in 58 localized and 14 metastatic PC patients at diagnosis, 7 ARAT-naïve and 6 ARAT-resistant CRPC patients. LncRNA H19 expression in PC tissue was examined using published data. In order to analyze the role of H19, the prognosis was analyzed in PC patients and proteomic analysis was performed in 22Rv1 PC cells. RESULTS: RNA-sequencing revealed that AR-regulated RNAs were most enriched in EVs after acquiring ARAT-resistance. Among them, up-regulation of AR signaling-related lncRNAs (PCAT1, H19, HOXA-11AS, ZEB1-AS1, ARLNC1, PART1, CTBP1-AS and PCA3) was confirmed by ddPCR. H19 contained in EVs (EV-H19) was significantly increased among ARAT-resistant patients compared to ARAT-naïve CRPC or metastatic PC patients. In PC tissue, H19 was negatively correlated with AR protein and AR-activity score and up-regulated in neuroendocrine CRPC tissue with low AR expression. Furthermore, EV-H19 expression was significantly associated with worse outcome to androgen-deprivation therapy. Proteomic analysis demonstrated that H19 knockdown enhanced PC-related protein expression. CONCLUSION: EV-H19 may negatively correlate with AR-signaling activity and could be a marker to diagnose ARAT-resistance among CRPC patients.

Artificial intelligence for evaluating the risk of gastric cancer: reliable detection and scoring of intestinal metaplasia with deep learning algorithms.

BACKGROUND AND AIMS: Gastric cancer (GC) is associated with chronic gastritis. To evaluate the risk, the Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) system was constructed and showed a higher GC risk in stage III or IV patients, determined by the degree of intestinal metaplasia (IM). Although the OLGIM system is useful, evaluating the degree of IM requires substantial experience to produce precise scoring. Whole-slide imaging is becoming routine, but most artificial intelligence (AI) systems in pathology are focused on neoplastic lesions. METHODS: Hematoxylin and eosin-stained slides were scanned. Images were divided into each gastric biopsy tissue sample and labeled with an IM score. IM was scored as follows: 0 (no IM), 1 (mild IM), 2 (moderate IM), and 3 (severe IM). Overall, 5753 images were prepared. A deep convolutional neural network (DCNN) model, ResNet50, was used for classification. RESULTS: ResNet50 classified images with and without IM with a sensitivity of 97.7% and specificity of 94.6%. IM scores 2 and 3, involved as criteria of stage III or IV in the OLGIM system, were classified by ResNet50 in 18%. The respective sensitivity and specificity values of classifying IM between scores 0 and 1 and 2 and 3 were 98.5% and 94.9%, respectively. The IM scores classified by pathologists and the AI system were different in only 438 images (7.6%), and we found that ResNet50 tended to miss small foci of IM but successfully identified minimal IM areas that pathologists missed during the review. CONCLUSIONS: Our findings suggested that this AI system would contribute to evaluating the risk of GC accuracy, reliability, and repeatability with worldwide standardization.

X-ray-Fluorescence-Based Screening Method for Uranium in Contaminated Brackish Water Using Graphene Oxide Nanosheets.

In the event of uranium release into the environment due to an accident, confirming the presence of uranium contamination is difficult because uranium is a naturally occurring element. In this study, we developed a method based on X-ray fluorescence (XRF) for the facile screening of uranium in brackish water samples in the event of an accident in a coastal area. Graphene oxide nanosheets were added to uncontaminated brackish water sampled from different sites to adsorb the uranium present in the samples, if any. The graphene oxide nanosheets were then collected using a membrane filter and analyzed using XRF. The results revealed that the signal intensity of the U Lα peak was proportional to the salinity. Hence, uranium contamination could be confirmed when the intensity of the U Lα peak was significantly greater than that derived from the background uranium content, as estimated from the salinity value. Thus, in the event of an accident, the salinity of the collected brackish water should be measured, and XRF analysis should be performed using our developed method. This method is useful for screening brackish water for uranium contamination.

Spermidine enhances the efficacy of adjuvant in HBV vaccination in mice.

Background: Various vaccine adjuvants have been developed to eliminate HBV from patients with chronic HBV infection. In addition, spermidine (SPD), a type of polyamine, has been reported to enhance the activity of immune cells. In the present study, we investigated whether the combination of SPD and vaccine adjuvant enhances the HBV antigen-specific immune response to HBV vaccination. Methods: Wild-type and HBV-transgenic (HBV-Tg) mice were vaccinated 2 or 3 times. SPD was orally administered in drinking water. Cyclic guanosine monophosphate-AMP (cGAMP) and nanoparticulate CpG-ODN (K3-SPG) were used as the HBV vaccine adjuvants. The HBV antigen-specific immune response was evaluated by measuring the HBsAb titer in blood collected over time and the number of interferon-γ producing cells by enzyme-linked immunospot assay. Results: The administration of HBsAg + cGAMP + SPD or HBsAg + K3-SPG + SPD significantly enhanced HBsAg-specific interferon-γ production by CD8 T cells from wild-type and HBV-Tg mice. The administration of HBsAg, cGAMP, and SPD increased serum HBsAb levels in wild-type and HBV-Tg mice. In HBV-Tg mice, the administration of SPD + cGAMP or SPD + K3-SPG with HBV vaccination significantly reduced HBsAg levels in the liver and serum. CONCLUSIONS: These results indicate that the combination of HBV vaccine adjuvant and SPD induces a stronger humoral and cellular immune response through T-cell activation. These treatments may support the development of a strategy to completely eliminate HBV.

Administration of spermidine attenuates concanavalin A-induced liver injury.

A previous study revealed that treatment with the anticoagulant heparin attenuated concanavalin A (ConA)-induced liver injury. The administration of spermidine (SPD) increased urokinase-type plasminogen activator (uPA) levels in the serum. uPA is clinically used for the treatment of some thrombotic diseases such as cerebral infarction. Therefore, SPD may attenuate ConA-induced liver injury that is exacerbated by blood coagulation. The present study investigated the effect of SPD on liver injury in mice with autoimmune hepatopathy induced by ConA. A model of liver injury was created by intravenous injection of ConA into mice. SPD was administered in free drinking water and was biochemically and pathologically examined over time. The administration of SPD to ConA-treated mice significantly reduced liver injury. However, SPD treatment upregulated the mRNA expression of TNF-α and IFN-ϒ in the livers of ConA-treated mice. In contrast, the mRNA expression of tissue factor in the livers of SPD-treated mice was decreased after ConA injection. The frequency of lymphocytes and lymphocyte activation were not affected by SPD administration in ConA-treated mice. SPD treatment increased uPA levels in the serum and decreased the level of D-dimer in ConA-treated mice. Moreover, SPD decreased fibrin in the livers of ConA-treated mice. These results indicated that SPD treatment increased anticoagulant ability by increasing of uPA and attenuated ConA-induced liver injury.

Cytomorphology and Gene Expression Signatures of Anchorage-independent Aggregations of Oral Cancer Cells.

BACKGROUND/AIM: Cancer cells with high anchorage independence can survive and proliferate in the absence of adhesion to the extracellular matrix. Under anchorage-independent conditions, cancer cells adhere to each other and form aggregates to overcome various stresses. In this study, we investigated the cytomorphology and gene expression signatures of oral cancer cell aggregates. MATERIALS AND METHODS: Two oral cancer-derived cell lines, SAS and HSC-3 cells, were cultured in a low-attachment plate and their cytomorphologies were observed. The transcriptome between attached and detached SAS cells was examined using gene expression microarrays. Subsequently, gene enrichment analysis and Ingenuity Pathway Analysis were performed. Gene expression changes under attached, detached, and re-attached conditions were measured via RT-qPCR. RESULTS: While SAS cells formed multiple round-shaped aggregates, HSC-3 cells, which had lower anchorage independence, did not form aggregates efficiently. Each SAS cell in the aggregate was linked by desmosomes and tight junctions. Comparative transcriptomic analysis revealed 1,698 differentially expressed genes (DEGs) between attached and detached SAS cells. The DEGs were associated with various functions and processes, including cell adhesion. Moreover, under the detached condition, the expression of some epithelial genes (DSC3, DSP, CLDN1 and OCLN) were up-regulated. The changes in both cytomorphology and epithelial gene expression under the detached condition overall returned to their original ones when cells re-attached. CONCLUSION: The results suggest specific cytomorphological and gene expression changes in oral cancer cell aggregates. Our findings provide insights into the mechanisms underlying anchorage-independent oral cancer cell aggregation and reveal previously unknown potential diagnostic and therapeutic molecules.

Testicular teratomagenesis from primordial germ cells with overexpression of germinal center-associated nuclear protein.

Testicular teratomas are the major histologic type of testicular germ cell tumors and their incidence continues to grow. Moreover, teratomas can develop from undifferentiated cells in induced pluripotent stem (iPS) cell transplantation therapy, seriously hampering the progress of regenerative medicine. Germinal center-associated nuclear protein (GANP) is thought to be important to the biogenetic control of primordial germ cells and is among the genes susceptible to testicular germ cell tumors. Thus, we analyzed the expression of GANP in human testicular postpubertal-type teratomas and established a novel mouse model to reveal the association between GANP and teratomagenesis. We analyzed 31 cases of human testicular postpubertal-type teratomas and, in all cases, GANP was overexpressed. The aberrant expression was also detected in germ cell neoplasia in situ accompanied by the teratoma. GANP expression was particularly high in the epithelia of the epidermis, cutaneous appendages, and trachea-like ciliated epithelium. To further clarify the association between GANP and teratomagenesis, we established a novel teratomagenesis mouse model (CAG-ganpTg mice). In the GANP-teratoma mice, GANP-overexpressing teratomas were more frequent at the testes and the middle portion of the uterus than has been seen in the previously established mouse models. In conclusion, GANP is overexpressed in testicular postpubertal-type teratomas and is an essential teratomagenic factor. We also found that CAG-ganpTg mice are useful mouse models of teratomagenesis that mimics human midline teratomas and that teratomas may originate from the overexpression of GANP in primordial germ cells.

The Philosophy of Dermatopathology.

Diagnostic pathology involves studying sample cells and tissues obtained from the specific lesions of interest [...].

Transcriptome of sessile serrated adenoma/polyps is associated with MSI-high colorectal cancer and decreased expression of CDX2.

The objective of this study was to elucidate the molecular background of sessile serrated adenoma/polyp (SSA/P) endoscopically resected with comprehensive gene expression analysis. Gene expression profiling was performed for 10 tumor-normal pairs of SSA/P. Cluster analysis, gene set enrichment analysis (GSEA), and consensus molecular subtype (CMS) classification of colorectal cancer (CRC) were applied to our transcriptome analysis. Unsupervised cluster analysis showed that the gene expression profile of SSA/Ps is different from that of adjacent normal epithelial cells, even in the very early stage of tumorigenesis. According to the CMS classification, our microarray data indicated that SSA/Ps were classified as CMS1. GSEA demonstrated a strong association between SSA/P and microsatellite instability-high (MSI-H) CRC (p < 10-5 ). Transcriptome analysis of five MSI-related genes (MSH2, MSH6, MLH1, PMS1, and PMS2) and five CRC-related genes (BRAF, KRAS, APC, TP53, and CDX2) showed that CDX2 expression was most severely decreased in SSA/P. Immunohistochemical staining confirmed that CDX2 protein was reduced compared with the surrounding mucosa. Direct sequencing of the BRAF gene showed that the BRAF V600E mutation was detected in only nine of 36 cases. In a mouse model, BRAF, APC, or CDX2 deficiency indicated that the gene expression pattern with loss of CDX2 is more similar to our SSA/Ps compared with those induced by BRAF or APC mutation. Transcriptome analysis of SSA/Ps showed characteristic gene expression with a strong resemblance to MSI-H CRC. Downregulation of CDX2 expression is an essential molecular mechanism involved in the initial stage of SSA/P tumorigenesis. (UMIN000027365).

Development of Gluten-Free Rice Flour Noodles That Suit the Tastes of Japanese People.

Gluten-free rice flour noodles with a flavor and texture profile preferred by the Japanese people were developed. The rice noodles contained potato starch (PS) as a binder. "Koshihikari" was selected from several candidate varieties based on its pasting properties. Since the Japanese people prefer the chewy texture of wheat flour "Udon" noodles, first, the stress-strain characteristics of "Udon" noodles in Japan were quantified, using a mechanical test. Next, different formulations of rice noodles were prepared by changing the amount of PS blended into the noodles. The mechanical tests on wheat and rice noodles show that rice noodles made from 85% rice flour and 15% PS have a texture similar to that of "Udon" noodles. Brown rice noodles containing roasted brown rice flour were also developed. Since brown rice flour hinders the binding of the dough, it was necessary to increase the amount of PS to increase the binding of roasted brown rice flour. Finally, noodles with 70% white rice flour, 10% brown rice flour, and 20% PS were produced. The gas chromatography-mass spectrometry analysis of the volatile compounds contained in white rice noodles and brown rice noodles identified the volatile compounds characteristic each of type.

Sulfated Glycans Recognized by S1 Monoclonal Antibody can Serve as a Diagnostic Marker for Malignant Pleural Mesothelioma.

PURPOSE: Malignant pleural mesothelioma (MPM) is a malignant neoplasm of the pleura caused by asbestos exposure. For diagnosis of MPM, immunohistochemistry using multiple markers is recommended to rule out differential diagnoses, such as pulmonary adenocarcinoma. However, the specificity of currently used markers is not fully satisfactory. We previously developed a monoclonal antibody named S1, which recognizes 6-sulfo sialyl Lewis x, an L-selectin ligand expressed on high endothelial venules. During the screening process, we discovered that this antibody stained normal pleural mesothelium. This finding prompted us to hypothesize that the epitope recognized by S1 might serve as a new diagnostic marker for MPM. METHODS: To test this hypothesis, we immunostained human MPM (n = 22) and lung adenocarcinoma (n = 25) tissues using S1 antibody. RESULTS: 77.3% of MPM were S1 positive, and if limited to epithelioid type, the positivity rate was 100%, while that of lung adenocarcinoma was only 36.0%. Statistical analysis revealed a significant difference in the S1 positivity rate between each disease. Furthermore, immunohistochemistry using a series of anti-carbohydrate antibodies combined with glycosidase digestion revealed the structure of sulfated glycans expressed in MPM to be 6-sulfo sialyl N-acetyllactosamine attached to core 2-branched O-glycans. CONCLUSION: We propose that the S1 glycoepitope could serve as a new diagnostic marker for MPM.

Histology of Cardiac Sarcoidosis with Novel Considerations Arranged upon a Pathologic Basis.

Sarcoidosis is a rare disease of isolated or diffuse granulomatous inflammation. Although any organs can be affected by sarcoidosis, cardiac sarcoidosis is a fatal disorder, and it is crucial to accurately diagnose it to prevent sudden death due to dysrhythmia. Although endomyocardial biopsy is invasive and has limited sensitivity for identifying granulomas, it is the only modality that yields a definitive diagnosis of cardiac sarcoidosis. It is imperative to develop novel pathological approaches for the precise diagnosis of cardiac sarcoidosis. Here, we aimed to discuss commonly used diagnostic criteria for cardiac sarcoidosis and to summarize useful and novel histopathologic criteria of cardiac sarcoidosis. While classical histologic observations including noncaseating granulomas and multinucleated giant cells (typically Langhans type) are the most important findings, others such as microgranulomas, CD68+ CD163- pro-inflammatory (M1) macrophage accumulation, CD4/CD8 T-cell ratio, Cutibacterium acnes components, lymphangiogenesis, confluent fibrosis, and fatty infiltration may help to improve the sensitivity of endomyocardial biopsy for detecting cardiac sarcoidosis. These novel histologic findings are based on the pathology of cardiac sarcoidosis. We also discussed the principal histologic differential diagnoses of cardiac sarcoidosis, such as tuberculosis myocarditis, fungal myocarditis, giant cell myocarditis, and dilated cardiomyopathy.

Spread of vimentin-immunoreactive cells within the plaque-like lesion in the spinal anterior horn of a patient with post-poliomyelitis syndrome.

A Japanese man in the present study experienced acute weakness in his right leg as a two year old. The strength in his leg gradually recovered and developed, and he could play golf and climb mountains up to around the age of 50. From approximately 55 years of age, he became unable to stand up from a stooped position. Muscle weakness and atrophy spread to his right arm, and an electromyography revealed a neurogenic pattern in his lower and upper extremities. The patient was diagnosed as having post-poliomyelitis syndrome (PPS). Numbness in both the legs and pain in the buttocks occurred after 60 years of age. Computed tomography and magnetic resonance imaging at that time revealed spondylosis and protrusion of an osteophye in lower thoracic vertebrae compressing the second lumbar segment of the spinal cord. He died of malignant lymphoma and acute interstitial pneumonia at 80 years of age. Pathological examination revealed transverse myelopathy at the second lumbar segment of the spinal cord and total necrosis. The anterior horn and the intermediate zone of the third and fourth lumbar segments of the spinal cord on the right side were atrophic and diffusely gliotic. An oval-shaped plaque-like lesion was observed in the right anterior horn at the third and fourth lumbar segments of the spinal cord. Neurons and synaptophysin immunoreactivity had completely disappeared in the plaque-like lesion. A striking spread of vimentin-immunoreactive cells was found corresponding to the lesion, while glial fibrillary acidic protein-immunoreactive astrocytes existed evenly in the anterior horn and intermediate zone on both sides of the third and fourth lumber segments of the spinal cord. Virological examination using the autopsied materials was negative for poliovirus. Neither transactivation response DNA-binding protein of 43 kDa-immunoreactive inclusion nor Bunina body was seen in the spinal cord. The present paper demonstrates new findings of a noteworthy response of the vimentin-immunoreactive cells within the peculiar "plaque-like lesion" in the PPS.

Increased chemosensitivity via BRCA2-independent DNA damage in DSS1- and PCID2-depleted breast carcinomas.

Breast cancer, the most common malignancy among women, is closely associated with mutations in the tumor suppressor gene BRCA. DSS1, a component of the TRanscription-EXport-2 (TREX-2) complex involved in transcription and mRNA nuclear export, stabilizes BRCA2 expression. DSS1 is also related to poor prognosis in patients with breast cancer owing to the induction of chemoresistance. Recently, BRCA2 was shown to be associated with the TREX-2 component PCID2, which prevents DNA:RNA hybrid R-loop formation and transcription-coupled DNA damage. This study aimed to elucidate the involvement of these TREX-2 components and BRCA2 in the chemosensitivity of breast carcinomas. Our results showed that compared with that in normal breast tissues, DSS1 expression was upregulated in human breast carcinoma, whereas PCID2 expression was comparable between normal and malignant tissues. We then compared patient survival time among groups divided by high or low expressions of DSS1, BRCA2, and PCID2. Increased DSS1 expression was significantly correlated with poor prognosis in recurrence-free survival time, whereas no differences were detected in the high and low BRCA2 and PCID2 expression groups. We performed in vitro analyses, including propidium iodide nuclear staining, single-cell gel electrophoresis, and clonogenic survival assays, using breast carcinoma cell lines. The results confirmed that DSS1 depletion significantly increased chemosensitivity, whereas overexpression conferred chemoresistance to breast cancer cell lines; however, BRCA2 expression did not affect chemosensitivity. Similar to DSS1, PCID2 expression was also inversely correlated with chemosensitivity. These results strongly suggest that DSS1 and PCID2 depletion is closely associated with increased chemosensitivity via BRCA2-independent DNA damage. Together with the finding that DSS1 is not highly expressed in normal breast tissues, these results demonstrate that DSS1 depletion confers a druggable trait and may contribute to the development of novel chemotherapeutic strategies to treat DSS1-depleted breast carcinomas independent of BRCA2 mutations.

EWSR1-CREM fusion in pulmonary mesenchymal neoplasm showing distinctive clear cell morphology.

EWSR1-CREM gene fusions were recently discovered in several mesenchymal and epithelial tumors, including myxoid mesenchymal tumors of the central nervous system, rare cases of soft tissue clear cell sarcoma and angiomatoid fibrous histiocytoma, and hyalinizing clear cell carcinoma, which implicates the potential phenotypic diversities of tumors harboring an EWSR1-CREM fusion. We herein present an exceedingly indolent pulmonary mesenchymal tumor showing distinctive clinicopathological features. This tumor histologically displayed a small nest and alveolar pattern consisting of monomorphic clear cells intermingled with dilated anastomosing vasculature. Immunophenotypically, tumor cells were positive for vimentin and focally positive for synaptophysin, but negative for many immunohistochemical panels including keratins, EMA, desmin, mesothelial markers, melanotic markers, smooth muscle actin, inhibin and S-100 protein. Interestingly, RNA sequencing identified an in-frame EWSR1-CREM fusion, which was confirmed by subsequent real-time/reverse transcription polymerase chain reaction and fluorescence in situ hybridization assay. Clinical follow-up showed no evidence of recurrence and metastasis. Our pathological findings further expand the phenotypic spectrum of tumors associated with EWSR1-CREM fusions, implying the emergence of a possible novel tumor entity.

The critical role of germinal center-associated nuclear protein in cell biology, immunohematology, and hematolymphoid oncogenesis.

Germinal center-associated nuclear protein (GANP) is a unique and multifunctional protein that plays a critical role in cell biology, neurodegenerative disorders, immunohematology, and oncogenesis. GANP is an orthologue of Saccharomyces Sac3, one of the components of the transcription export 2 (TREX-2) complex and a messenger RNA (mRNA) nuclear export factor. GANP is widely conserved in all mammals, including humans. Although GANP was originally discovered as a molecule upregulated in the germinal centers of secondary lymphoid follicles in peripheral lymphoid organs, it is expressed ubiquitously in many tissues. It serves numerous functions, including making up part of the mammalian TREX-2 complex; mRNA nuclear export via nuclear pores; prevention of R-loop formation, genomic instability, and hyper-recombination; and B-cell affinity maturation. In this review, we first overview the extensive analyses that have revealed the basic functions of GANP and its ancestor molecule Sac3, including mRNA nuclear export and regulation of R-loop formation. We then describe how aberrant expression of GANP is significantly associated with cancer development. Moreover, we discuss a crucial role for GANP in B-cell development, especially affinity maturation in germinal centers. Finally, we illustrate that overexpression of GANP in B cells leads to lymphomagenesis resembling Hodgkin lymphoma derived from germinal center B cells, and that GANP may be involved in transdifferentiation of B cells to macrophages, which strongly affects Hodgkin lymphomagenesis.