Retrospective immunohistochemical analysis of human cytomegalovirus infection in the placenta and its association with fetal growth restriction

Objectives

Fetal human cytomegalovirus (HCMV) infection might be involved in fetal growth restriction (FGR). Maternal serostatus and the prevalence of congenital HCMV infection are affected by various factors, such as socioeconomic status and ethnicity. Therefore, the prevalence of congenital HCMV-related FGR should be examined in each region.

Methods

Seventy-eight cases of FGR with delivery between January 2012 and January 2017 at Fujita Health University Hospital were studied. Twenty-one non-FGR cases were also included as a control group. Placental sections obtained from the FGR and control cases were immunostained with two primary antibodies for detecting immediate early antigens.

Results

Nineteen placental samples from FGR cases with another etiology were excluded. Finally, 59 placental samples from FGR cases of unknown etiology were included in the pathological analysis. Four of 59 (6.8%) placental samples were positive for HCMV antigen. All four positive cases were stained with the M0854 antibody, and there were no positive case with the MAB810R antibody. Neither maternal nor infantile clinical features were different between the HCMV-positive and -negative FGR cases. A pathological examination showed a hematoma in three of four cases and infarction in two of four cases.

Conclusions

HCMV antigen was detected in 6.8% of placental samples obtained from FGR cases without an obvious etiology. No remarkable maternal or neonatal clinical features discriminated HCMV-related FGR from FGR due to other causes. Vasculitis and inflammation might play important roles in the pathogenesis of HCMV-related FGR.

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.

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-ganp^Tg 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-ganp^Tg 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.

Heterotopic ossification in primary rectal cancer with squamous cell carcinoma-like differentiation

OBJECTIVES

Heterotopic ossification (HO), which occurs when bone tissue forms outside the skeleton, is extremely rare in rectal cancer. Adenocarcinoma is the histological type of all reported primary colorectal cancers with HO. However, in the present case, we observed areas of adenocarcinoma with squamous cell carcinoma-like differentiation. Here we conducted histopathological and immunohistochemical analyses to identify the mechanisms of HO development, to differentiate between adenocarcinoma and squamous cell carcinoma-like phenotypes, and to understand the associated prognostic implications.

CASE REPORT

A 62-year-old woman was admitted to our hospital with symptoms of intermittent hematochezia without abdominal pain. Colonoscopy revealed stenosis with a protuberant mass in the rectum. Abdominopelvic contrast-enhanced computed tomography showed irregular wall thickness of the rectum, multiple lymph node metastases, and liver metastases. The rectal tumor exhibited calcified deposits with marked hyperintensity. We then performed Hartmann's operation and D3 lymph node resection. The biopsy specimen revealed tubular and solid adenocarcinoma nests and squamous carcinoma-like components over a necrotic extent without secreted mucin. She received chemotherapy (mFOLFOX6 with bevacizumab) as the first option and is alive 5 months after surgery.

CONCLUSION

To the best of our knowledge, this is the first case of heterotopic ossification in a primary rectal cancer with squamous cell carcinoma-like differentiation that was surgically resected. This case suggests that BMP-2 transformed fibroblasts and pluripotent stem cells into osteocytes. We conclude that the squamous cell carcinoma-like lesion was squamous metaplasia of adenocarcinoma.

Rotavirus incapable of NSP6 expression can cause diarrhea in suckling mice

The group A rotavirus (RVA) genome comprising 11 double-stranded RNAs encodes six structural proteins (VP1-VP4, VP6, and VP7) and six non-structural proteins (NSP1-NSP6). Among these 12 rotaviral proteins, NSP6 has been less studied as to its function. We previously prepared a recombinant NSP6-deficient RVA derived from simian strain SA11-L2 by reverse genetics, and found that the NSP6-deficient virus grew well in cell culture, although its growth was less abundant than that of the parental SA11-L2 strain. In this study, we examined the potency of a recombinant RVA incapable of NSP6 expression to cause diarrhoea in suckling mice. The suckling mice infected with the NSP6-deficient virus apparently experienced diarrhoea, although the symptom was milder and the duration of diarrhoea was shorter than in the mice infected with the authentic SA11-L2 strain. Thus, together with the results obtained for cultured cells in the previous study, it can be concluded that NSP6 is not necessarily required for replication and pathogenicity in vitro and in vivo.

Colonic Lymphoid Follicle Hyperplasia after Gastrectomy in Rats

Nodular lymphoid hyperplasia (NLH) of the human colon has been associated with multiple diseases and symptoms. Causes include food allergies, infections, inflammatory bowel disease, and immunodeficiency, and gastrectomy is not usually considered to be the etiology. Nine rats two weeks after total gastrectomy and 12 control rats were sacrificed and submitted for histological examination. In the gastrectomy group, we found lymphoid hyperplasia throughout the entire colon mucosa. The cross-sectional area of lymphoid follicles was increased to be five-fold larger than that in the rats in the control group (sham surgery). Lymphoid follicles were classified into primary and secondary follicles according to the presence/absence of germinal centers; the gastrectomy group had a significantly larger number of secondary follicles. When T cell and B cell classification of lymphocytes was performed, there was no difference between gastrectomy and control groups at T:B = 40:60. When the lymphoid follicles were classified, the proportion of T lymphocytes increased in the secondary follicle (T:B = 40:60) compared with in the primary follicle (T:B = 20:80). Gastrectomy significantly activated lymphocytic intestinal immunity by altering the intestinal environment, causing colonic NLH. Gastrectomy in rats is a good animal model for the study of NLH in colorectal diseases.

Expression status of p53 and organic cation transporter 1 is correlated with poor response to preoperative chemotherapy in esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is a highly malignant neoplasm. DNA-damaging drugs, such as cisplatin (CDDP) and 5-fluorouracil (5-FU), are most frequently used in preoperative chemotherapy for ESCC. However, the response to preoperative chemotherapy varies among patients. p53, encoded by TP53, participates in apoptotic pathways following chemotherapy with DNA-damaging drugs, and mutation of TP53 contributes to chemoresistance. Organic cation transporter 1 (OCT1) participates in the uptake of CDDP, and its reduced expression is associated with CDDP resistance. The aim of this study was to evaluate the predictive impact of the expression status of p53 and OCT1 in response to preoperative chemotherapy in ESCC.

Methods

We retrospectively assessed 66 ESCC patients who received preoperative chemotherapy with CDDP/5-FU (CF) or docetaxel/CDDP/5-FU (DCF). p53 and OCT1 expression in pretreatment biopsy specimens was immunohistochemically determined and correlated with histological response to preoperative chemotherapy.

Results

p53 with wild-type (p53^WT-ex) and mutant-type (p53^MT-ex) expression patterns was identified in 40.9% and 59.1% of patients, respectively. High expression of OCT1 (OCT1^High) was detected in 45.5%, and the remaining 54.5% showed low expression (OCT1^Low). In a univariate analysis of the entire cohort, p53^MT-ex was significantly correlated with poor response (P = 0.026), whereas OCT1^Low showed marginal significance (P = 0.091). In a combined analysis, tumors with either p53^MT-ex or OCT1^Low showed a significant correlation with poor response compared with tumors with both p53^WT-ex and OCT1^High (P < 0.001). The sensitivity, specificity, and accuracy of combined p53/OCT1 were 93.9%, 47.1%, and 81.8%, respectively. Multivariate analysis identified p53 (P = 0.017), OCT1 (P = 0.032), and combined p53/OCT1 (P < 0.001) as independent predictors of histological response. When samples were stratified according to chemotherapy regimen in the univariate analysis, combined p53/OCT1 was the only significant factor for poor response in the CF (P = 0.011) and DCF (P = 0.021) groups, whereas p53 showed no statistical significance.

Conclusions

Our results suggest that either p53^MT-ex or OCT1^Low expression in pretreatment biopsy specimens may be a potential predictor of poor response to preoperative chemotherapy with the CF-based regimens in ESCC, although the specificity needs to be improved.

Behçet's Disease with Bilateral Renal Infarction Due to Mucormycosis

We herein report a case of Behçet's disease with renal infarction due to mucormycosis. A 76-year-old man with entero-Behçet's disease had been treated with glucocorticoid and tumor necrosis factor (TNF) inhibitors. His entero-Behçet's disease was refractory to these treatments, and ileocecal resection was performed. After the operation, renal infarction that was unresponsive to anticoagulation therapy developed. He ultimately died of renal failure due to renal infarction. At the autopsy, histopathology of abundant hyphae in the renal vessel wall revealed mucormycosis. Renal mucormycosis is an important cause of renal failure with renal infarction in immunocompromised patients.

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.

Visualization of Three-Dimentional Stigmoid Body in FFPE and Ultrathin Sections of Mouse

Huntingtin-associated protein 1 (HAP1) is abundantly expressed in the neurons of the central nervous system and forms unique intracytoplasmic inclusions of unknown function called "stigmoid bodies" (STBs). Transmission electron microscopy has revealed that the STBs are aggregates of granules containing cavities with a diameter of 0.5-3 µm. Small STBs fuse to form larger STBs, the size of which is said to vary depending on the developmental growth stage and brain region. Light microscopy can only reveal that these STBs have similar circular shapes, due to its limited resolution. Therefore, light microscopy is only fit for the study of the STB distribution and quantitative changes. We, herein, suggest the adoption of correlative light and electron microscopy, that combines confocal laser scanning microscopy and scanning electron microscopy, as the method allowing us to identify the HAP1-positive STBs in formalin-fixed paraffin-embedded (FFPE) sections. This approach allows us to study the three-dimensional morphology of immunolabeled objects in histopathological specimens. The STBs in FFPE sections of murine hypothalami reflected the transmission electron microscopic images of Epon-embedded STBs, although we were not able to observe any organelle covering the STBs of the FFPE sections. Furthermore, we were able to reconstruct the three-dimensional structure of the STB and we identified it to be of spherical form, covered with mitochondria and rough endoplasmic reticulum, and bearing a cluster of cavities in the center. In the future, we might gain new insights by comparing the 3D structure of the STB between different neurons and under a variety of conditions.

High Levels of Dietary Lard or Sucrose May Aggravate Lysosomal Renal Injury in Non-Obese, Streptozotocin-Injected CD-1 Mice Provided Isocaloric Diets

Daily fat and sugar intake has increased in Japan, while total energy intake has decreased. However, the number of type 2 diabetes mellitus patients has increased, and this often causes renal injury characterized by autophagic vacuoles. Although many studies with comparisons of high fat or sugar versus a normal macronutrient balanced diet have been reported, there are few studies that equalized calorie intake and body weights. In the current study, AIN93M diets (CONT group) with matching energy content with lard derived high saturated fat (LARD group), soybean oil derived unsaturated fat (SOY OIL group) and sucrose (SUCROSE group) were provided to compare their effects on renal morphology in streptozotocin-injected CD-1 mice without causing obesity. The number of renal tubular vacuoles was higher in SUCROSE and slightly higher in LARD compared with CONT mice, and was higher in LARD and SUCROSE compared with SOY OIL mice. Most of those vacuoles were LAMP1-positive, a marker of lysosomal autophagy. These results suggest that despite identical energy contents, diets with high sucrose or saturated fat compared to unsaturated fat may aggravate lysosomal renal injury in a non-obese, streptozotocin-induced model of diabetes mellitus.

Primary central nervous system lymphomas with massive intratumoral hemorrhage: Clinical, radiological, pathological, and molecular features of six cases

Primary central nervous system lymphomas (PCNSLs) rarely exhibit intratumoral hemorrhage. The differential diagnosis of hemorrhagic neoplasms of the central nervous system (CNS) currently includes metastatic carcinomas, melanomas, choriocarcinomas, oligodendrogliomas, and glioblastomas. Here we present the clinical, radiological, pathological, and molecular genetic features of six cases of PCNSL associated with intratumoral hemorrhage. The median age of patients was 75 years, with male predominance. While conventional PCNSLs were associated with low cerebral blood volume (CBV), perfusion magnetic resonance imaging (MRI) revealed elevated CBV in three cases, consistent with vascular proliferation. All six cases were diagnosed pathologically as having diffuse large B-cell lymphoma (DLBCL) with a non-germinal center B-cell-like (non-GCB) phenotype; marked histiocytic infiltrates and abundant non-neoplastic T-cells were observed in most cases. Expression of vascular endothelial growth factor and CD105 in the lymphoma cells and the small vessels, respectively, suggested angiogenesis within the neoplasms. Neoplastic cells were immunohistochemically negative for programmed cell death ligand 1 (PD-L1), while immune cells in the microenvironment were positive for PD-L1. Mutations in the MYD88 gene (MYD88) (L265P) and the CD79B gene (CD79B) were detected in five and one case, respectively. As therapeutic modalities used for PCNSLs differ from those that target conventional hemorrhagic neoplasms, full tissue diagnoses of all hemorrhagic CNS tumors are clearly warranted.

CEBPγ facilitates lamellipodia formation and cancer cell migration through CERS6 upregulation

Ceramide synthase 6 (CERS6) promotes lung cancer metastasis by stimulating cancer cell migration. To examine the underlying mechanisms, we performed luciferase analysis of the CERS6 promoter region and identified the Y-box as a cis-acting element. As a parallel analysis of database records for 149 non-small-cell lung cancer (NSCLC) cancer patients, we screened for trans-acting factors with an expression level showing a correlation with CERS6 expression. Among the candidates noted, silencing of either CCAAT enhancer-binding protein γ (CEBPγ) or Y-box binding protein 1 (YBX1) reduced the CERS6 expression level. Following knockdown, CEBPγ and YBX1 were found to be independently associated with reductions in ceramide-dependent lamellipodia formation as well as migration activity, while only CEBPγ may have induced CERS6 expression through specific binding to the Y-box. The mRNA expression levels of CERS6, CEBPγ, and YBX1 were positively correlated with adenocarcinoma invasiveness. YBX1 expression was observed in all 20 examined clinical lung cancer specimens, while 6 of those showed a staining pattern similar to that of CERS6. The present findings suggest promotion of lung cancer migration by possible involvement of the transcription factors CEBPγ and YBX1.

Elevation of the serotonin-derived quinone, tryptamine-4,5-dione, in the intestine of ICR mice with dextran sulfate-induced colitis

Inflammatory bowel diseases, including Crohn's disease and ulcerative colitis, are chronic inflammatory disorders associated with oxidative stress. The intestines produce 5-hydroxytryptamine that may negatively affect disease state under inflammatory conditions when overproduced. 5-Hydroxytryptamine is a substrate for myeloperoxidase and is converted into reactive tryptamine-4,5-dione. Here, an experimental colitis model was established through oral administration of 5% dextran sulfate sodium to ICR mice for 7 days. Furthermore, the formation of tryptamine-4,5-dione in the colorectal mucosa/submucosa and colorectal tissue was analyzed by chemical and immunochemical methodologies. First, free tryptamine-4,5-dione in the homogenate was chemically trapped by o-phenylenediamine and analyzed as the stable phenazine derivative. Tryptamine-4,5-dione localization as adducted proteins in the colorectal tissue was immunohistochemically confirmed, and as demonstrated by both methods, this resulted in the significant increase of tryptamine-4,5-dione in dextran sulfate sodium-challenged mice compared with control mice. Immunohistochemical staining confirmed tryptamine-4,5-dione-positive staining at the myeloperoxidase accumulation site in dextran sulfate sodium-challenged mice colorectal tissue. The tryptamine-4,5-dione locus in the mice was partly matched with that of a specific marker for myeloperoxidase, halogenated tyrosine. Overall, the results possibly indicate that tryptamine-4,5-dione is generated by neutrophil myeloperoxidase in inflammatory tissue and may contribute to the development of inflammatory bowel disease.

Mutual stain conversion between Giemsa and Papanicolaou in cytological images using cycle generative adversarial network

Objective

Papanicolaou and Giemsa stains used in cytology have different characteristics and complementary roles. In this study, we focused on cycle-consistent generative adversarial network (CycleGAN), which is an image translation technique using deep learning, and we conducted mutual stain conversion between Giemsa and Papanicolaou in cytological images using CycleGAN.

Methods

A total of 191 Giemsa-stained images and 209 Papanicolaou-stained images were collected from 63 patients with lung cancer. From those images, 67 images from nine cases were used for testing and the remaining images were used for training. For data augmentation, the number of training images was increased by rotation and inversion, and the images were pipelined to CycleGAN to train the mutual conversion process involving Giemsa- and Papanicolaou-stained images. Three pathologists and three cytotechnologists performed visual evaluations of the authenticity of cell nuclei, cytoplasm, and cell layouts of the test images translated using CycleGAN.

Results

As a result of converting Giemsa-stained images into Papanicolaou-stained images, the background red blood cell patterns present in Giemsa-stained images disappeared, and cell patterns that reproduced the shape and staining of the cell nuclei and cytoplasm peculiar to Papanicolaou staining were obtained. Regarding the reverse-translated results, nuclei became larger, and red blood cells that were not evident in Papanicolaou-stained images appeared. After visual evaluation, although actual images exhibited better results than converted images, the results were promising for various applications.

Discussion

The stain translation technique investigated in this paper can complement specimens under conditions where only single stained specimens are available; it also has potential applications in the massive training of artificial intelligence systems for cell classification, and can also be used for training cytotechnologist and pathologists.

Tryptophan 2,3-dioxygenase in tumor cells is associated with resistance to immunotherapy in renal cell carcinoma

Indoleamine 2,3‐dioxygenase 1 (IDO1) is a key enzyme associated with immunomodulation through its regulation of the tryptophan‐kynurenine (Kyn) pathway in advanced cancers, including metastatic renal cell carcinoma (mRCC). However, the failure of IDO1 inhibitors when used in combination with immune checkpoint inhibitors (ICIs), as observed in clinical trials, raises a number of questions. This study aimed to investigate the association of tryptophan 2,3‐dioxygenase (TDO) and IDO1 with cancer development and resistance to immunotherapy in patients with RCC. In our analysis of RCC tissue samples, tissue Kyn levels were elevated in advanced‐stage RCC and correlated well with TDO expression levels in RCC tumor cells. In patients with mRCC, TDO rather than IDO1 was expressed in RCC tumor cells, showing a strong association with Kyn expression. Furthermore, immunohistochemical staining of TDO was strongly associated with the staining intensity of forkhead box P3, as well as ICI therapy response and survival in patients with mRCC. Our study is the first to show that TDO expression in tumor tissues is associated with progression and survival, confirming its potential as a predictive biomarker of primary resistance to immunotherapy in patients with mRCC. Our findings suggest that strategies aimed at inhibiting TDO, rather than IDO1, in combination with ICI therapy may aid in the control of mRCC progression.

Nuclear staining of claudin-18 is a new immunohistochemical marker for diagnosing intramucosal well-differentiated gastric adenocarcinoma

Diagnosis of gastric adenocarcinoma using small biopsy samples is occasionally difficult. Various markers have been employed for improving the diagnostic accuracy, but there remains room for improvement. A total of 129 endoscopically biopsied samples were studied, consisting of 104 intramucosal tubular adenocarcinomas, 24 non-cancerous lesions and one cancer sample originally suspected of non-cancer but revised as cancer after immunostaining. We evaluated the association between histopathology and immunohistochemical expression of MUC1, HER2, p53, CEA, E-cadherin, β-catenin and claudin-18. Regarding β-catenin and claudin-18, not only membranous expression (β-catenin(M) and claudin-18(M)) but also nuclear expression (β-catenin(N) and claudin-18(N)) were analyzed. When subtyped with mucin core protein expression, the gastric-type cancers dominantly expressed claudin-18(M), while claudin-18(N) was significantly encountered in intestinal- and mixed-types. Expression of MUC1 (P = 0.0010), HER2 (P = 0.0173), p53 (P = 0.0002), CEA (P = 0.0019) and claudin-18(N) (P < 0.0001) revealed significant correlation with gastric cancers. Negative correlation of claudin-18(M) (P = 0.0125) was also noted. MUC1 and p53 were negative in non-cancer lesions. The non-cancer group exceptionally expressed HER2 and β-catenin(N). Membranous expression of E-cadherin was consistent in both groups. Logistic regression analysis showed that MUC1 (P = 0.0086), p53 (P = 0.0031), claudin-18(M) (P = 0.0158) and claudin-18(N) (P = 0.0190) were independently associated with gastric cancers. Nuclear expression of claudin-18 should be the novel diagnostic marker for gastric cancer.

Transduced caudal-type homeobox (CDX) 2/CDX1 can induce growth inhibition on CDX-deficient gastric cancer by rapid intestinal differentiation

Intestinal metaplasia induced by ectopic expression of caudal‐type homeobox (CDX)2 and/or CDX1 (CDX) is frequently observed around gastric cancer (GC). Abnormal expression of CDX is also observed in GC and suggests that inappropriate gastrointestinal differentiation plays essential roles in gastric tumorigenesis, but their roles on tumorigenesis remain unelucidated. Publicly available databases show that GC patients with higher CDX expression have significantly better clinical outcomes. We introduced CDX2 and CDX1 genes separately into GC‐originated MKN7 and TMK1 cells deficient in CDX. Marked suppression of cell growth and dramatic morphological change into spindle‐shaped flat form were observed along with induction of intestinal marker genes. G0‐G1 growth arrest was accompanied by changed expression of cell cycle‐related genes but not with apoptosis or senescence. Microarray analyses additionally showed decreased expression of gastric marker genes and increased expression of stemness‐associated genes. Hierarchical clustering of 111 GC tissues and 21 non‐cancerous gastric tissues by selected 18 signature genes based on our transcriptome analyses clearly categorized the 132 tissues into non‐cancer, “CDX signature”‐positive GC, and “CDX signature”‐negative GC. Gene set enrichment analysis indicated that “CDX signature”‐positive GC has lower malignant features. Immunohistochemistry of 89 GC specimens showed that 50.6% were CDX2‐deficient, 66.3% were CDX1‐deficient, and 44.9% were concomitant CDX2/CDX1‐deficient, suggesting that potentially targetable GC cases by induced intestinal differentiation are quite common. In conclusion, exogenous expression of CDX2/CDX1 can lead to efficient growth inhibition of CDX‐deficient GC cells. It is based on rapidly induced intestinal differentiation, which may be a future therapeutic strategy.

Expression of Gastric Markers Is Associated with Malignant Potential of Nonampullary Duodenal Adenocarcinoma

BACKGROUND

Sporadic nonampullary duodenal epithelial tumors (NADETs) are uncommon, and thus their clinicopathological features have not been fully assessed.

AIMS

In this study, we have analyzed a series of early sporadic NADETs, focusing on various immunohistological features.

METHODS

We conducted a multicenter retrospective analysis of 68 patients with endoscopically resected sporadic NADETs. Associations between immunohistological features and clinicopathological features were statistically analyzed.

RESULTS

The 68 patients consisted of 46 men (68%) and 22 women (32%) with a mean age of 60.7 ± 12.2 years (range 37-85 years). The 68 tumors were composed of 39 adenomas (57%) and 29 early-stage adenocarcinomas (43%). Duodenal adenocarcinomas were larger in size than adenomas and had papillary architecture in their pathological diagnosis with statistical significance. Duodenal adenocarcinomas also demonstrated a significantly higher expression of gastric markers (MUC5AC and MUC6) and a higher MIB-1 index. Duodenal adenomas were contrastively apt to express intestinal markers (MUC2, CDX1 and CDX2). Of the 68 cases analyzed, there were only 3 tumors positive for p53 staining, all of which were adenocarcinoma. When 7 submucosal invasive cancers and 21 intramucosal cancers were compared, submucosal invasion was positively associated with expression of MUC5AC. Also, submucosal invasion showed strong association with double-positivity of MUC5AC and MUC6.

CONCLUSIONS

Our results indicate that immunohistochemical evaluation is useful for predicting malignant potential of NADETs, especially focusing on the expression of gastrointestinal markers.

Nectin1 expression is frequently decreased in gastric cancers

Gastric cancer (GC) is rich in many different histological types, but how the histological pattern is defined remains to be proved. The relation between GC histological types and the expression of nectin1, which is one of the cell adhesion molecules that composes adherens junction, has not been reported. According to a publicly available database of 406 GC patients, the median overall survival of Nectin1 high expression patients was 55.4 months and that of low expression patients was 25.6 months (P = 0.0246). Using surgically or endoscopically resected GC samples, nectin1 expression was analyzed by immunohistochemistry. Nectin1 expressed at adherens junction in all the normal epithelial cells. However, nectin1 expressed not at adherens junction but at apical membrane in epithelial cells in intestinal metaplasia. The expression pattern of nectin1 in intestinal type GC resembled to intestinal metaplasia. In order to analyze the difference in nectin1 expression between GC histological types, a total of 116 intestinal type GC and 33 diffuse type GC. The expression of necitin1 in diffuse type GC (3.0%) was remarkably decreased compared to that in intestinal type GC (65.5%) (P < 0.0001). In conclusion, this is the first report showing an association between nectin1 expression and histological subtypes of GC.

Potential role for nectin-4 in the pathogenesis of pre-eclampsia: a molecular genetic study

BACKGROUND

Nectins are cell adhesion molecules that play a pivotal role in adherens junctions and tight junctions. Our previous study using whole-genome oligonucleotide microarrays revealed that nectin-4 was upregulated in pre-eclamptic placentas. We investigated the role of nectin-4 in the etiology of pre-eclampsia.

METHODS

We investigated the expression of nectin-4 using real-time RT-PCR, western blot and immunostaining. Additionally, we performed matrigel invasion assay and cytotoxicity assay using cells overexpressing the nectin-4.

RESULTS

NECTIN4 transcripts were elevated in pre-eclamptic placentas relative to uncomplicated pregnancies. Nectin-4 protein levels in pre-eclamptic placentas were higher on a semi-quantitative western blot. Nectin-4 was localized at the apical cell membrane in syncytiotrophoblast cells and not at the adherens junctions. Nectin-4 was also detected in cytotrophoblasts and a subset of cells in the decidua. Nectin-4 overexpressing trophoblast cells migrated normally in the matrix. However, Natural killer (NK) cells showed a strong cytotoxic effect against nectin-4 overexpressing trophoblast cells. No causative genetic variation was evident in the NECTIN4 gene from a pre-eclamptic placenta.

CONCLUSIONS

There are as yet unknown factors that induce nectin-4 overexpression in trophoblast cells that may contribute to abnormal placentation via an aberrant immune response and the onset of a pre-eclamptic pregnancy.

Cytokeratin 13, Cytokeratin 17, and Ki-67 Expression in Human Acquired Cholesteatoma and Their Correlation With Its Destructive Capacity

OBJECTIVES

Cholesteatoma is a nonneoplastic destructive lesion of the temporal bone with debated pathogenesis and bone resorptive mechanism. Both molecular and cellular events chiefly master its activity. Continued research is necessary to clarify factors related to its aggressiveness. We aimed to investigate the expression of Ki-67, cytokeratin 13 (CK13) and cytokeratin 17 (CK17) in acquired nonrecurrent human cholesteatoma and correlate them with its bone destructive capacity.

METHODS

A prospective quantitative immunohistochemical study was carried out using fresh acquired cholesteatoma tissues (n=19), collected during cholesteatoma surgery. Deep meatal skin tissues from the same patients were used as control (n=8). Cholesteatoma patients were divided into 2 groups and compared (invasive and noninvasive) according to a grading score for bone resorption based upon clinical, radiologic and intraoperative findings. To our knowledge, the role of CK17 in cholesteatoma aggressiveness was first investigated in this paper.

RESULTS

Both Ki-67 and CK17 were significantly overexpressed in cholesteatoma than control tissues (P<0.001 for both Ki-67 and CK17). In addition, Ki-67 and CK17 were significantly higher in the invasive group than noninvasive group of cholesteatoma (P=0.029, P=0.033, respectively). Furthermore, Ki-67 and CK17 showed a moderate positive correlation with bone erosion scores (r=0.547, P=0.015 and r=0.588, P=0.008, respectively). In terms of CK13, no significant difference was found between cholesteatoma and skin (P=0.766).

CONCLUSION

Both Ki-67 and CK17 were overexpressed in cholesteatoma tissue and positively correlated with bone resorption activity. The concept that Ki-67 can be a predictor for aggressiveness of cholesteatoma was supported. In addition, this is the first study demonstrating CK17 as a favoring marker in the aggressiveness of acquired cholesteatoma.

Extranodal NK/T-cell Lymphoma, Nasal Type Accompanied by PR3-ANCA-associated Glomerulonephritis

A 62-year-old man exhibiting nasal obstruction and glomerulonephritis with proteinase 3-antineutrophil cytoplasmic antibodies (PR3-ANCAs) was diagnosed with extranodal NK/T-cell lymphoma, nasal type (ENKL) with infiltration of neutrophils with apoptosis. Chemoradiotherapy reduced the tumor, improved the renal function, and decreased the PR3-ANCA levels. ANCA-positivity is observed in immunoinsufficient diseases, in which neutrophils lead to apoptosis and translocate intracellular granules, such as PR3, to the cell surface, triggering the production of ANCAs. In our case, the PR3-ANCA production was derived from the expression of PR3 on the cell surface of apoptotic neutrophils. This is the first report on ENKL describing the mechanism of ANCA development.

Hemophagocytic Lymphohistiocytosis in a Fatal Case of Severe Fever with Thrombocytopenia Syndrome

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease caused by a novel Bunyavirus with a high mortality rate. We herein report a fatal case of an 86-year-old woman with SFTS complaining of a fever, fatigue, and bicytopenia. Her condition deteriorated with rapid progression of bleeding tendency, disturbance of consciousness, and multiple organ failure leading to death on Day 6 of her illness. The histopathological findings in the autopsy revealed marked infiltration of macrophages with hemophagocytosis in the bone marrow, liver, and spleen leading to a diagnosis of hemophagocytic lymphohistiocytosis (HLH). HLH might be a critical pathogenesis in fatal cases of SFTS.

18F-FDG PET imaging for identifying the dynamics of intestinal disease caused by SFTSV infection in a mouse model

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease that causes fever, enteritis, thrombocytopenia, and leucopenia and can be fatal in up to 30% of cases. However, the mechanism of severe disease is not fully understood. Molecular imaging approaches, such as positron-emission tomography (PET), are functional in vivo imaging techniques that provide real-time dynamics of disease progression, assessments of pharmacokinetics, and diagnoses for disease progression. Molecular imaging also potentially provides useful approaches to explore the pathogenesis of viral infections. Thus, the purpose of this study was to image the pathological features of SFTSV infection in vivo by PET imaging. In a mouse model, we showed that 18F-FDG accumulations clearly identified the intestinal tract site as a pathological site. We also demonstrated that 18F-FDG PET imaging can assess disease progression and response to antiserum therapy within the same individual. This is the first report demonstrating a molecular imaging strategy for SFTSV infection. Our results provide potentially useful information for preclinical studies such as the elucidation of the mechanism of SFTSV infection in vivo and the assessment of drugs for SFTS treatment.

Visualization of Neutrophil Extracellular Traps and Fibrin Meshwork in Human Fibrinopurulent Inflammatory Lesions: III. Correlative Light and Electron Microscopic Study

Neutrophil extracellular traps (NETs) released from dead neutrophils at the site of inflammation represent webs of neutrophilic DNA stretches dotted with granule-derived antimicrobial proteins, including lactoferrin, and play important roles in innate immunity against microbial infection. We have shown the coexistence of NETs and fibrin meshwork in varied fibrinopurulent inflammatory lesions at both light and electron microscopic levels. In the present study, correlative light and electron microscopy (CLEM) employing confocal laser scanning microscopy and scanning electron microscopy was performed to bridge light and electron microscopic images of NETs and fibrin fibrils in formalin-fixed, paraffin-embedded, autopsied lung sections of legionnaire’s pneumonia. Lactoferrin immunoreactivity and 4'-6-diamidino-2-phenylindole (DAPI) reactivity were used as markers of NETs, and fibrin was probed by fibrinogen gamma chain. Of note is that NETs light microscopically represented as lactoferrin and DAPI-colocalized dots, 2.5 μm in diameter. CLEM gave super-resolution images of NETs and fibrin fibrils: “Dotted” NETs were ultrastructurally composed of fine filaments and masses of 58 nm-sized globular materials. A fibrin fibril consisted of clusters of smooth-surfaced filaments. NETs filaments (26 nm in diameter) were significantly thinner than fibrin filaments (295 nm in diameter). Of note is that CLEM was applicable to formalin-fixed, paraffin-embedded sections of autopsy material.

Visualization of Neutrophil Extracellular Traps and Fibrin Meshwork in Human Fibrinopurulent Inflammatory Lesions: I. Light Microscopic Study

Neutrophil extracellular traps (NETs) are extracellular fibrillary structures composed of degraded chromatin and granules of neutrophil origin. In fibrinopurulent inflammation such as pneumonia and abscess, deposition of fibrillar eosinophilic material is a common histopathological finding under hematoxylin-eosin staining. Expectedly, not only fibrin fibrils but also NETs consist of the fibrillar material. The aim of the present study is to analyze immunohistochemically how NETs are involved in the inflammatory process. Archival formalin-fixed, paraffin-embedded sections accompanying marked neutrophilic infiltration were the target of analysis. Neutrophil-associated substances (citrullinated histone H3, lactoferrin, myeloperoxidase and neutrophil elastase) were evaluated as NETs markers, while fibrinogen gamma chain was employed as a fibrin marker. Light microscopically, the fibrils were categorized into three types: thin, thick and clustered thick. Lactoferrin represented a good and stable NETs marker. Thin fibrils belonged to NETs. Thick fibrils are composed of either mixed NETs and fibrin or fibrin alone. Clustered thick fibrils were solely composed of fibrin. Neutrophils were entrapped within the fibrilllar meshwork of the thin and thick types. Apoptotic cells immunoreactive to cleaved caspase 3 and cleaved actin were dispersed in the NETs. In conclusion, NETs and fibrin meshwork were consistently recognizable by immunostaining for lactoferrin and fibrinogen gamma chain.

Visualization of Neutrophil Extracellular Traps and Fibrin Meshwork in Human Fibrinopurulent Inflammatory Lesions: II. Ultrastructural Study

Neutrophil extracellular traps (NETs) represent an extracellular, spider’s web-like structure resulting from cell death of neutrophils. NETs play an important role in innate immunity against microbial infection, but their roles in human pathological processes remain largely unknown. NETs and fibrin meshwork both showing fibrillar structures are observed at the site of fibrinopurulent inflammation, as described in our sister paper [Acta Histochem. Cytochem. 49; 109–116, 2016]. In the present study, immunoelectron microscopic study was performed for visualizing NETs and fibrin fibrils (thick fibrils in our tongue) in formalin-fixed, paraffin-embedded sections of autopsied lung tissue of legionnaire’s pneumonia. Lactoferrin and fibrinogen gamma chain were utilized as markers of NETs and fibrin, respectively. Analysis of immuno-scanning electron microscopy indicated that NETs constructed thin fibrils and granular materials were attached onto the NETs fibrils. The smooth-surfaced fibrin fibrils were much thicker than the NETs fibrils. Pre-embedding immunoelectron microscopy demonstrated that lactoferrin immunoreactivities were visible as dots on the fibrils, whereas fibrinogen gamma chain immunoreactivities were homogeneously observed throughout the fibrils. Usefulness of immunoelectron microscopic analysis of NETs and fibrin fibrils should be emphasized.

Enzyme-labeled Antigen Method: Development and Application of the Novel Approach for Identifying Plasma Cells Locally Producing Disease-specific Antibodies in Inflammatory Lesions

In chronic inflammatory lesions of autoimmune and infectious diseases, plasma cells are frequently observed. Antigens recognized by antibodies produced by the plasma cells mostly remain unclear. A new technique identifying these corresponding antigens may give us a breakthrough for understanding the disease from a pathophysiological viewpoint, simply because the immunocytes are seen within the lesion. We have developed an enzyme-labeled antigen method for microscopic identification of the antigen recognized by specific antibodies locally produced in plasma cells in inflammatory lesions. Firstly, target biotinylated antigens were constructed by the wheat germ cell-free protein synthesis system or through chemical biotinylation. Next, proteins reactive to antibodies in tissue extracts were screened and antibody titers were evaluated by the AlphaScreen method. Finally, with the enzyme-labeled antigen method using the biotinylated antigens as probes, plasma cells producing specific antibodies were microscopically localized in fixed frozen sections. Our novel approach visualized tissue plasma cells that produced 1) autoantibodies in rheumatoid arthritis, 2) antibodies against major antigens of Porphyromonas gingivalis in periodontitis or radicular cyst, and 3) antibodies against a carbohydrate antigen, Strep A, of Streptococcus pyogenes in recurrent tonsillitis. Evaluation of local specific antibody responses expectedly contributes to clarifying previously unknown processes in inflammatory disorders.

Tofla virus: A newly identified Nairovirus of the Crimean-Congo hemorrhagic fever group isolated from ticks in Japan

Ixodid ticks transmit several important viral pathogens. We isolated a new virus (Tofla virus: TFLV) from Heamaphysalis flava and Heamaphysalis formsensis in Japan. The full-genome sequences revealed that TFLV belonged to the genus Nairovirus, family Bunyaviridae. Phylogenetic analyses and neutralization tests suggested that TFLV is closely related to the Hazara virus and that it is classified into the Crimean-Congo hemorrhagic fever group. TFLV caused lethal infection in IFNAR KO mice. The TFLV-infected mice exhibited a gastrointestinal disorder, and positron emission tomography-computed tomography images showed a significant uptake of (18)F-fluorodeoxyglucose in the intestinal tract. TFLV was able to infect and propagate in cultured cells of African green monkey-derived Vero E6 cells and human-derived SK-N-SH, T98-G and HEK-293 cells. Although TFLV infections in humans and animals are currently unknown, our findings may provide clues to understand the potential infectivity and to develop of pre-emptive countermeasures against this new tick-borne Nairovirus.

Coated Glass Slides TACAS Are Applicable to Heat-Assisted Immunostaining and In Situ Hybridization at the Electron Microscopy Level

We performed pre-embedding electron microscopic study for visualizing the antigen and genome of severe fever with thrombocytopenia syndrome (SFTS) virus in the cytoplasm of macrophages of the human splenic red pulp, both requesting preheating treatment of sections. To pursue this, coated glass slides with unique characteristics are needed. Namely, during staining they must prevent detaching off sections, but after staining the sections must be transferred to epoxy resin. Aminopropyltriexoxysilane-coated glass slides, widely used for immunostaining, were resistant to transfer to epoxy resin. In contrast, coated glass slides designated as Thinlayer Advanced Cytology Assay System (TACAS) were suitable for this purpose. The technique is also applicable to the coated glass slide-requiring cytology practice, in which immunocytochemical evaluation is needed after cell transfer to another glass slide.

Application of an enzyme-labeled antigen method for visualizing plasma cells producing antibodies against Strep A, a carbohydrate antigen of Streptococcus pyogenes, in recurrent tonsillitis

Streptococcus pyogenes is the main causative pathogen of recurrent tonsillitis. Histologically, lesions of recurrent tonsillitis contain numerous plasma cells. Strep A is an antigenic carbohydrate molecule on the cell wall of S. pyogenes. As expected, plasma cells in subjects with recurrent tonsillitis secrete antibodies against Strep A. The enzyme‐labeled antigen method is a novel histochemical technique that visualizes specific antibody‐producing cells in tissue sections by employing a biotin‐labeled antigen as a probe. The purpose of the present study was to visualize plasma cells producing antibodies reactive with Strep A in recurrent tonsillitis. Firstly, the lymph nodes of rats immunized with boiled S. pyogenes were paraformaldehyde‐fixed and specific plasma cells localized in frozen sections with biotinylated Strep A. Secondly, an enzyme‐labeled antigen method was used on human tonsil surgically removed from 12 patients with recurrent tonsillitis. S. pyogenes genomes were PCR‐detected in all 12 specimens. The emm genotypes belonged to emm12 in nine specimens and emm1 in three. Plasma cells producing anti‐Strep A antibodies were demonstrated in prefixed frozen sections of rat lymph nodes, 8/12 human specimens from patients with recurrent tonsillitis but not in two control tonsils. In human tonsils, Strep A‐reactive plasma cells were observed within the reticular squamous mucosa and just below the mucosa, and the specific antibodies belonged to either IgA or IgG classes. Our technique is effective in visualizing immunocytes producing specific antibodies against the bacterial carbohydrate antigen, and is thus a novel histochemical tool for analyzing immune reactions in infectious disorders.

New Grocott Stain without Using Chromic Acid

We established a new “ecological” Grocott stain for demonstrating fungi, based upon a 4R principle of refusal, reduction, reuse, and recycle of waste management. Conventional Grocott stain employs environmentally harsh 5% chromic acid for oxidization. Initially, we succeeded in reducing the concentration of chromic acid from 5% to 1% by incubating the solution at 60°C and using five-fold diluted chromic acid solution at which point it was reusable. Eventually, we reached the refusal level where 1% periodic acid oxidization was efficient enough, when combined with preheating of sections in the electric jar, microwave oven, or pressure pan. For convenience sake, we recommend pressure pan heating in tap water for 10 min. Stainability of fungi in candidiasis and aspergillosis was comparable with conventional Grocott stain, while Mucor hyphae showed enhanced staining. The modified sequence was further applicable to detecting a variety of mycotic pathogens in paraffin sections. Our environmentally-friendly Grocott stain also has the advantage of avoiding risk of human exposure to hexavalent chromium solution in the histopathology laboratory. The simple stain sequence is can be easily applied worldwide.

Gli regulates MUC5AC transcription in human gastrointestinal cells

MUC5AC is a well-known gastric differentiation marker, which has been frequently used for the classification of stomach cancer. Immunohistochemistry revealed that expression of MUC5AC decreases accompanied with increased malignant property of gastric mucosa, which further suggests the importance of MUC5AC gene regulation. Alignment of the 5′-flanking regions of MUC5AC gene of 13 mammal species denoted high homology within 200 bp upstream of the coding region. Luciferase activities of the deletion constructs containing upstream 451 bp or shorter fragments demonstrated that 15 bp region between −111 and −125 bp plays a critical role on MUC5AC promoter activity in gastrointestinal cells. We found a putative Gli-binding site in this 15 bp sequence, and named this region a highly conserved region containing a Gli-binding site (HCR-Gli). Overexpression of Gli homologs (Gli1, Gli2, and Gli3) clearly enhanced MUC5AC promoter activity. Exogenous modulation of Gli1 and Gli2 also affected the endogenous MUC5AC gene expression in gastrointestinal cells. Chromatin immunoprecipitation assays demonstrated that Gli1 directly binds to HCR-Gli: Gli regulates MUC5AC transcription via direct protein-DNA interaction. Conversely, in the 30 human cancer cell lines and various normal tissues, expression patterns of MUC5AC and Gli did not coincide wholly: MUC5AC showed cell line-specific or tissue-specific expression whereas Gli mostly revealed ubiquitous expression. Luciferase promoter assays suggested that the far distal MUC5AC promoter region containing upstream 4010 bp seems to have several enhancer elements for gene transcription. In addition, treatments with DNA demethylation reagent and/or histone deacetylase inhibitor induced MUC5AC expression in several cell lines that were deficient in MUC5AC expression. These results indicated that Gli is necessary but not sufficient for MUC5AC expression: namely, the multiple regulatory mechanisms should work in the distal promoter region of MUC5AC gene.

In situ visualization of plasma cells producing antibodies reactive to Porphyromonas gingivalis in periodontitis: the application of the enzyme-labeled antigen method

Porphyromonas gingivalis is a keystone periodontal pathogen. Histologocally, the gingival tissue in periodontitis shows dense infiltration of plasma cells. However, antigens recognized by antibodies secreted from the immunocytes remain unknown. The enzyme-labeled antigen method was applied to detecting plasma cells producing P. gingivalis-specific antibodies in biopsied gingival tissue of periodontitis. N-terminally biotinylated P. gingivalis antigens, Ag53 and four gingipain domains (Arg-pro, Arg-hgp, Lys-pro and Lys-hgp) were prepared by the cell-free protein synthesis system using wheatgerm extract. With these five labeled proteins as probes, 20 lesions of periodontitis were evaluated. With the AlphaScreen method, antibodies against any one of the five P. gingivalis antigens were detected in 11 (55%) serum samples and 17 (85%) tissue extracts. Using the enzyme-labeled antigen method on paraformaldehyde-fixed frozen sections of gingival tissue, plasma cells were labeled with any one of the five antigens in 17 (94%) of 18 specimens, in which evaluable plasma cells were detected. The positivity rates in periodontitis were significantly higher than those found previously in radicular cysts (20% in sera and 33% in tissue extracts with the AlphaScreen method, and 25% with the enzyme-labeled antigen method). Our findings directly indicate that antibodies reactive to P. gingivalis are locally produced in the gingival lesions, and that inflammatory reactions against P. gingivalis are involved in periodontitis.

Cathepsin E is a marker of gastric differentiation and signet-ring cell carcinoma of stomach: a novel suggestion on gastric tumorigenesis

Gastric cancer (GC) presents various histological features, though the mechanism underlying its diversity is seldom elucidated. It is mainly classified into well differentiated tubular adenocarcinoma (tub1), moderately differentiated tubular adenocarcinoma (tub2), poorly differentiated adenocarcinoma (por), signet-ring cell carcinoma (sig), mucinous adenocarcinoma (muc), and papillary adenocarcinoma (pap). By screening, we found cathepsin E (CTSE) expresses universally in sig-type, occasionally in por-type, and rarely in tub1/tub2-type GC cell lines. In surgically-resected specimens, CTSE was immunostained in 50/51 sig-type (98.0%), 3/10 tub1-type (30.0%), 7/18 tub2-type (38.9%), 15/26 por-type (57.7%), 4/10 pap-type (40.0%), and 0/3 muc-type (0.0%) GC. In endoscopically-resected specimens, 6/7 sig-type (85.7%), 7/52 tub1-type (13.7%), 5/12 tub2-type (41.7%), 2/7 pap-type (28.6%) GC and 0/6 adenoma (0.0%) expressed CTSE. For non-malignant tissues, CTSE is universally expressed in normal fundic, pyloric, and cardiac glands of stomach, but hardly in other digestive organs. In the precancerous intestinal metaplasia of stomach, CTSE is mostly observed in mixed gastric-and-intestinal type and deficient in solely-intestinal type. CTSE expression is positively correlated with gastric marker MUC5AC (p<0.0001) and negatively correlated with intestinal marker MUC2 (p = 0.0019). For sig-type GC, in both tumors and background mucosa, expression of MUC5AC and CTSE is high whereas that of MUC2 is low, indicating that sig-type GC reflects the features of background mucosa. For gastric adenoma and tub1/tub2-type GC, more undifferentiated tumors tend to show higher expression of CTSE with MUC5AC and lower expression of MUC2 in tumors, but they tend to present lower expression of CTSE, MUC5AC and MUC2 in background mucosa. These suggest that more malignant gastric adenocarcinoma with stronger gastric and weaker intestinal properties tend to arise from background mucosa with decreased both gastric and intestinal features. In conclusion, CTSE is a marker of both gastric differentiation and signet-ring cell carcinoma, which should shed light on the mechanism of gastric tumorigenesis.

High-sensitivity epidermal growth factor receptor immunostaining for colorectal carcinomas, compared with EGFR PharmDx™: a study of diagnostic accuracy

Immunostaining for epidermal growth factor receptor (EGFR) is important in the contemporary therapeutic strategy of colorectal carcinomas. We tried to increase detection sensitivity, and compared the high-sensitivity EGFR immunostaining with a worldwide standard, EGFR PharmDx™ (Dako). In order to pursue high-sensitivity EGFR detection, deparaffinized sections were pressure-cooked in 1 mM EDTA solution, pH 8.0. Two mouse monoclonal antibodies against EGFR, clone EGFR2.5 and DAK-H1-WT, and six kinds of secondary detection reagents, including biotin-free catalyzed signal amplification (CSA II), Simple Stain MAX-PO, PolyVue, Novolink, EnVision™ FLEX+, and MACH3, were evaluated to compare the results with those with EGFR PharmDx™, employing a combination of 2-18-C9 as the primary monoclonal antibody and EnVision™ as the secondary reagent. Furthermore, we replaced EnVision™ in the EGFR PharmDx™ kit with CSAII. EGFR detection sensitivity was higher with DAK-H1-WT than with EGFR2.5, and among the secondary reagents, the strongest signals were observed with Novolink. All 30 colorectal carcinomas showed distinct expression of EGFR with our high-sensitivity EGFR immunostaining, while only 16 (53%) gave focal positivity with EGFR PharmDx™. When EnVision™ in EGFR PharmDx™ was replaced by CSA II, strong signals were seen in all cases, and the expression pattern was comparable with our sequence. Non-neoplastic crypt epithelial cells often showed weakly signal with the standard EGFR PharmDx™, but consistently revealed strong membrane staining in the two high-sensitivity sequences. EGFR PharmDx™ frequently gave false negativity. Importantly, EGFR was consistently and sensitively detected when the secondary polymer in the EGFR PharmDx™ kit was simply replaced by CSA II.

Novel approach to identifying autoantibodies in rheumatoid synovitis with a biotinylated human autoantigen library and the enzyme-labeled antigen method

Synovial tissue in rheumatoid arthritis (RA) shows dense infiltration of plasmacytes. The purpose of the present study is to identify and localize autoantibodies produced in these immunocytes in RA synovitis. We developed a novel screening system for detecting specific autoantigens. Protein antigens recognized by antibodies in the serum and synovial tissue extract from five RA patients were screened with the AlphaScreen method. For screening, a biotinylated human autoantigen library was constructed by the wheat germ cell-free protein synthesis system. The AlphaScreen analysis of 2183 proteins detected a limited number of antigens reactive with the serum and synovial tissue extract. Eighteen biotinylated proteins, containing top five showing high signals in each synovitis tissue extract, were utilized as probes for the enzyme-labeled antigen method, in order to visualize the site of specific antibody production in synovial lesions. Specific antibodies against two proteins, tripartite motif-containing 21 (TRIM21, also known as SSA/Ro52) and F-box only protein 2 (FBXO2), were visualized in the cytoplasm of plasmacytes in two RA synovitis lesions, respectively. Absorption experiments using unlabeled proteins confirmed the specificity of staining. No positive signals against these two proteins were identified in the additionally evaluated RA and osteoarthritis synovial lesions. The present study indicated 1) the usefulness of screening the human autoantigen library with the AlphaScreen assay for detecting autoantibodies in RA synovitis, and 2) the applicability of biotinylated proteins to the enzyme-labeled antigen method for visualizing the site of autoantibody production within the lesion.

Specific in situ visualization of plasma cells producing antibodies against Porphyromonas gingivalis in gingival radicular cyst: application of the enzyme-labeled antigen method

The enzyme-labeled antigen method was applied to visualize plasma cells producing antibodies to Porphyromonas gingivalis, flora of the human oral cavity. Antibodies to P. gingivalis have reportedly been detected in sera of patients with periodontitis. Biotinylated bacterial antigens, Ag53, and four gingipain domains (Arg-pro, Arg-hgp, Lys-pro, and Lys-hgp) were prepared by the cell-free protein synthesis system using the wheat germ extract. In paraformaldehyde-fixed frozen sections of rat lymph nodes experimentally immunized with Ag53-positive and Ag53-negative P. gingivalis, plasma cells were labeled with biotinylated Arg-hgp and Lys-hgp. Antibodies to Ag53 were detected only in the nodes immunized with Ag53-positive bacteria. In two of eight lesions of gingival radicular cyst with inflammatory infiltration, CD138-positive plasma cells in frozen sections were signalized for Arg-hgp and Lys-hgp. An absorption study using unlabeled antigens confirmed the specificity of staining. The AlphaScreen method identified the same-type antibodies in tissue extracts but not in sera. Antibodies to Ag53, Arg-pro, and Lys-pro were undetectable. In two cases, serum antibodies to Arg-hgp and Lys-hgp were AlphaScreen positive, whereas plasma cells were scarcely observed within the lesions. These findings indicate the validity of the enzyme-labeled antigen method. This is the very first application of this novel histochemical technique to human clinical samples.

MicroRNAs miR-199a-5p and -3p target the Brm subunit of SWI/SNF to generate a double-negative feedback loop in a variety of human cancers

The chromatin remodeling complex SWI/SNF is an important epigenetic regulator that includes one Brm or BRG1 molecule as catalytic subunit. Brm and BRG1 do not function identically, so this complex can regulate gene expression either positively or negatively, depending on the promoter to which it is recruited. Notably, Brm attenuation due to posttranscription suppression occurs often in human tumor cells, in which this event contributes to their oncogenic potential. Here, we report that the 3'-untranslated region of Brm mRNA has two sites that are efficiently targeted by the microRNAs miR-199a-5p and -3p, revealing a novel mechanism for modulation of Brm-type SWI/SNF activity. Computational mapping of the putative promoter region of miR-199a-2 (miPPR-199a-2) has defined it as the major contributing genetic locus for miR-199a-5p and-3p production in these tumor cell lines. We validated this predicted region by direct promoter analysis to confirm that Egr1 is a strong positive regulator of the miR-199a-2 gene. Importantly, we also showed that Egr1, miR-199a-5p, and miR-199a-3p are expressed at high levels in Brm-deficient tumor cell lines but only marginally in Brm-expressing tumor cells. Finally, we also obtained evidence that Brm negatively regulates Egr1. Together, our results reveal that miR-199a and Brm form a double-negative feedback loop through Egr1, leading to the generation of these two distinct cell types during carcinogenesis. This mechanism may offer a partial explanation for why miR-199a-5p and -3p have been reported to be either upregulated or downregulated in a variety of tumors.

Hepatitis C virus infection in a Japanese leprosy sanatorium for the past 67 years

Oku-Komyo-En is one of the national leprosy sanatoria, located on a small island in Setouchi city, Okayama prefecture of Japan since 1938. Since autopsies were carried out routinely on almost all patients who had died in the sanatorium up to 1980, approximately 1,000 formalin-fixed autopsy tissue samples were available for analysis. When these samples were reviewed, the pathological data indicated a sharp rise in the death rate caused by cirrhosis of the liver and hepatocellular carcinoma (HCC) since 1960 and 1970, respectively. Hepatitis C virus (HCV) infection is a common cause of HCC in Japan. The presence of HCV RNA was demonstrated in paraffin sections prepared from the autopsied liver tissue fixed in formalin for a prolonged period of time, by employing nested RT-PCR using type-specific primers. The data showed that HCV RNA was detectable in samples of the liver archived as early as 1940, representing the liver tissues kept in formalin for up to 67 years. HCV genotypes 1b and 2a were found by RT-PCR at 85.7% and 14.3%, respectively, in patients with leprosy.