EBV-positive pyothorax-associated lymphoma expresses CXCL9 and CXCL10 chemokines that attract cytotoxic lymphocytes via CXCR3.

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma associated with chronic inflammation (DLBCL-CI) develops in the setting of long-standing inflammation. This type of lymphoma may have specific expression profiles of chemokines involved in the pathogenesis of DLBCL-CI. EBV-positive pyothorax-associated lymphoma (PAL) is a prototype of DLBCL-CI and represents a valuable model for the study of this disease category. Using a panel of PAL cell lines, we found that PAL cells expressed and secreted C-X-C motif chemokine ligands 9 and 10 (CXCL9 and CXCL10), the ligands of CXCR3, in contrast to EBV-negative DLBCL cell lines, which did not. Culture supernatants from PAL cell lines attracted CXCR3-expressing CD4+ T cells, CD8+ T cells, and CD56+ natural killer cells from human peripheral blood mononuclear cells. PAL cells injected into mice also attracted CXCR3-positive cytotoxic lymphocytes that expressed interferon-γ. The expression of CXCL9 and CXCL10 was detected in PAL tumor biopsy samples from patients, and CXCR3-positive lymphocytes were abundant in the tissue samples. Collectively, these findings suggest that CXCL9 and CXCL10 are produced by PAL cells and can elicit cytotoxic responses via CXCR3. This chemokine system is also likely to contribute to tissue necrosis, which is a signature histological feature of DLBCL-CI. Further studies are warranted to determine whether the CXCL9-CXCL10/CXCR3 axis exerts antitumor effects in DLBCL-CI.

Detection of Merkel cell polyomavirus in multiple primary oral squamous cell carcinomas.

Oral microbiome studies have mainly focussed on bacteria, with the relationship between viruses and oral cancers remaining poorly understood. Oral cancers can develop even in the absence of any history of daily smoking or drinking. Oral cancer patients frequently have multiple primary cancers in the oral cavity and other organs, such as the upper gastrointestinal tract. Merkel cell polyomavirus (MCPyV) is a novel oncovirus identified from a subtype of skin cancer in 2008. In this study, we investigated the potential involvement of MCPyV in the pathogenesis of oral squamous cell carcinoma (OSCC). Participants comprised 115 Japanese patients with OSCC (single primary: 109 tumours in 109 patients; multiple primaries: 16 tumours in 6 patients) treated in our department between 2014 and 2017. DNA was extracted from formalin-fixed paraffin-embedded specimens of primary lesions. MCPyV DNA copy counts were analysed by quantitative real-time polymerase chain reaction. Twenty-four of the 115 patients (20.9%) were positive for MCPyV DNA. No association was found between presence or absence of MCPyV DNA and clinical characteristics other than number of primary lesions. The MCPyV DNA-positive rate was significantly higher for multiple primary OSCCs (62.5%, 10/16 tumours) than for single primary OSCCs (16.5%, 18/109 tumours; P < 0.001). Furthermore, MCPyV DNA load was significantly higher for patients with multiple primaries (P < 0.05). MCPyV was observed more frequently and DNA load was significantly higher with multiple primary OSCCs than with single primary OSCC. MCPyV may play some role as an oncovirus for multiple primary OSCCs.

Micromorphological observation of HLE cells under knockdown of Fascin using LV-SEM.

Liver cancer is one of the most prevalent cancers in Japan with hepatocellular carcinoma (HCC) as the major histological subtype. Successful novel treatments for HCC have been reported; however, recurrences or metastasis may occur, which results in poor prognoses and high mortality of HCC patients. Fascin, an actin-bundling protein, regulates cell adhesion, migration, and invasion. Its overexpression positively correlates with poor prognosis of malignant tumors, and Fascin is considered as one of the tumor biomarkers and therapeutic target proteins. In this study, we attempted to reveal the relationship between Fascin and HCC using HLE, one of the human HCC cell lines. We performed the study with classical immunocytochemistry and recently developed techniques, such as wound-healing assay, spheroid cultivation, and low-vacuum scanning electron microscopy (LV-SEM). Non-Fascin-knockdown (FKD) cell spheroid had a regular spherical appearance with tight cell-cell connections, while FKD cell spheroid had an irregular shape with loose cell-cell connections. Cells of non-FKD spheroid presented fibrous protrusions on the cell surface, contrarily, cells of FKD spheroids showed bulbous-shaped protrusions. Morphological observation of FKD and non-FKD HLE spheroids were performed using LV-SEM. Our study may help to reveal the roles of Fascin in the process of HCC formation and its malignancy.

Fascin expression persists with fibronectin in embryonic rat hepatoblasts.

Both fascin and fibronectin are known to play important roles in cell adhesion and migration. They are noted as tumor markers or inhibiting target for tumor treatment. In this study, embryonic rat livers were obtained to examine the expression of fascin and fibronectin during liver development. Then, the effect of fibronectin on fascin expression was investigated. At embryonic day (ED) 10.5, when the foregut endoderm began to form the liver bud and spread into the septum transversum, fibrous extracellular matrix was observed between the space where the liver bud and the septum transversum merged. At ED11.5, fibronectin was observed surrounding the cluster of fascin-positive hepatoblasts. At ED13.5, hematopoietic cells emerged and both fibronectin and fascin expression started to decline. Fascin and fibronectin appeared temporarily and disappeared by ED 14.5. Their expression was chronologically synchronized. Subsequently, the effect of fibronectin on fascin was examined by cultivation of hepatoblasts that were isolated from the ED13.5 rat liver. As a result, with fibronectin, fascin was positive in most hepatoblasts, although, without fibronectin, fascin expression was remarkably declined. Presently, there are few studies about the relationship between fascin and fibronectin. Our findings suggest that fibronectin could regulate fascin expression in rat hepatoblasts.

[Histiocytosis and virus: Merkel cell polyomavirus].

Histiocytosis is classified based on proliferating histiocyte-like cells. Langerhans cell histiocytosis (LCH) has several subtypes with various outcomes, from spontaneous to fatal regression, and these subtypes had been managed as different diseases. However, these different names of disease were unified to one disease named histiocytosis X since they are pathologically identical. Presently, LCH has been used as a unified name because proliferating cells have the characteristics of Langerhans cells. Since then, clonality and BRAF mutations have been reported, and their neoplastic characteristics has become clear; however, explaining its various subtypes is difficult with only the neoplastic character. Various relationships/correlations are also known between inflammatory factors and LCH subtypes. We have pointed out that the Merkel cell polyomavirus may be involved in LCH development and LCH is a disease with both neoplastic and reactive characters, that is, "a disease in which abnormal Langerhans-like cells with neoplastic character overreact to some triggers."

Prognostic significance of human papillomavirus 16 viral load level in patients with oropharyngeal cancer.

Human papillomavirus (HPV) infection in patients with oropharyngeal squamous cell carcinoma (OPSCC) is a major determinant for better prognosis. However, there remain HPV-positive patients who have poor outcomes. The stratification strategy for detecting high-risk patients among those with HPV-positive OPSCC has not been well delineated, especially for Asian patients. We undertook a retrospective cohort study on the survival rate of 89 Japanese patients diagnosed with primary OPSCC. The tumors were concurrently analyzed for the presence of HPV E6 DNA/mRNA, viral DNA load, p16 expression, viral physical status, and viral variant lineage. Human papillomavirus 16 viral DNA was found in 45 (51%) OPSCCs. Human papillomavirus 16 DNA-positive OPSCCs with higher viral load (classified as HPV16 DNA-medium/high OPSCCs) showed significantly favorable overall survival and progression-free survival compared with HPV16 DNA-positive OPSCCs with lower viral load (<10 copies/cell; HPV16 DNA-low OPSCCs) and HPV16 DNA-negative OPSCCs. E6 mRNA expression was observed in all HPV16 DNA-medium/high OPSCCs but not in HPV16 DNA-low OPSCCs. Notably, p16-positive and HPV16 DNA-negative/low OPSCCs showed significantly worse survival than p16-positive and HPV16 DNA-medium/high OPSCCs and resembled HPV-unrelated OPSCCs with regard to survival and risk factor profile. Although not significant, a trend toward shorter survival was observed for HPV16-integrated OPSCCs. Phylogenetic analysis revealed two major types of HPV16 variants termed Asian (A4) and European (A1/A2/A3) variants, but no difference in survival between these variants was observed. Altogether, these findings suggest that HPV viral load is a potentially informative factor for more accurate risk stratification of patients with OPSCC.

The Expression of Insulin-Like Growth Factor 2 Messenger RNA-Binding Protein 3 in Langerhans Cell Histiocytosis and Langerhans Cell Sarcoma.

Langerhans cell neoplasms, which include Langerhans cell histiocytosis and Langerhans cell sarcoma, are tumors that originate from dendritic cells. Langerhans cell sarcoma is defined as a high-grade neoplasm with overtly malignant cytological features and the Langerhans cell-like phenotype, and generally has a poorer prognosis and more aggressive phenotype than Langerhans cell histiocytosis. Insulin-like growth factor 2 messenger RNA-binding protein 3 (IGF2BP3 or IMP3) is an oncofetal protein that is expressed in various cancer types; its expression is often associated with a poor prognosis and aggressive phenotype. Here, we used immunohistochemistry to evaluate IGF2BP3 expression in Langerhans cell neoplasms. IGF2BP3 expression was scored as negative (< 1%) or positive (≥ 1%) by immunohistochemistry. All 4 patients with Langerhans cell sarcoma (100%) and 6 of 22 pediatric (age < 18 years) patients with Langerhans cell histiocytosis (27.3%) had positive results for IGF2BP3; however, 16 of 22 pediatric patients with Langerhans cell histiocytosis (72.7%) and all 15 adult (age ≥ 18 years) patients with Langerhans cell histiocytosis (100%) had a negative result. Among patients with Langerhans cell histiocytosis, IGF2BP3 expression was independent of sex, location, prognosis, and BRAF V600E staining results. Taken together, these results indicate that IGF2BP3 expression may be a helpful marker for distinguishing Langerhans cell sarcoma from Langerhans cell histiocytosis in adult patients.

Recurrence of Solitary Fibrous Tumor/Hemangiopericytoma Could Be Predicted by Ki-67 Regardless of Its Origin.

Since the discovery of the NAB2-STAT6 gene fusion in 2013, solitary fibrous tumor (SFT) and hemangiopericytoma (HPC) have been considered the same disease. STAT6 nuclear stain is approved as a highly sensitive and specific marker to diagnose SFT/HPC from other tumors with similar histology. As the next step, detection of fusion variants that may predict clinical malignancy of SFT/HPC has been attempted. However, no fusion variants with a clear relation to malignancy have been identified. In this study, the clinical and histological backgrounds of 23 Japanese patients diagnosed with SFT/HPC from 2000 to 2019 at Kochi University Hospital were examined to identify factors potentially related to recurrence. A significant relationship to recurrence was detected for mitosis ≥ 1/10 HPF (400×), necrosis, and Ki-67>5%. These findings indicate that a deliberate investigation of histological features such as mitosis and necrosis is crucial for the clinical observation of SFT/ HPC patients. In addition, Ki-67 was revealed to be a useful parameter to predict recurrence in SFT/HPC patients.

Lymph node retrieval after colorectal cancer surgery: a comparative study of the efficacy between the conventional manual method and a new fat dissolution method.

PURPOSE: This study compared the efficacy of two different methods for lymph node (LN) searching after colorectal cancer surgery: the fat dissolution and the conventional manual method. METHODS: For the fat dissolution method, we used a commercially available solution of collagenase and lipase (FD group). The primary endpoint was the number of identified LNs in the FD group compared to an historical control (control group) after adjusting by propensity score matching. RESULTS: Using 37 matched patients from each group, we identified 20.6 ± 7.2 LNs using the fat dissolution method compared to 13.5 ± 5.9 using the conventional method (t test, P < 0.01). Three patients in the FD group received an inappropriate LN examination in terms of number, while the number of the retrieved LNs was < 12 in 12 patients in the control group. The mean diameter of LNs without metastasis was 3.2 ± 1.9 mm in the FD group, and 40% of metastasis cases were found in LNs < 5 mm in diameter. A pathological examination confirmed that using the fat resolution method did not change the morphological or immunochemical staining findings. CONCLUSION: We demonstrated that fat dissolution had a positive impact on the number of retrieved LNs after colorectal cancer surgery without disturbing the microscopic observation.

[Recurrent High-grade Astroblastoma Treated with Stereotactic Radiotherapy:A Case Report].

INTRODUCTION: Astroblastoma is a rare, supratentorial glial tumor, occurring predominantly in children and young adults. However, treatment strategies have not yet been established for this rare disease. CASE PRESENTATION: A 6-year-old boy presented with headache and nausea. CT and MRI revealed a left frontal mass lesion with slight edema and macrocalcifications. Gross tumor resection was performed. Histological examination found neoplastic cells with astroblastic characteristics, and a striking perivascular array of pseudorosettes. The final diagnosis was high-grade astroblastoma. MRI 13 months after surgery suggested local recurrence, and an enlargement was found 3 months later. Stereotactic radiotherapy(SRT)was performed. MRI after SRT showed enhanced cyst formation around the tumor bed, suggesting tumor recurrence. However, 11C-methionine positron emission tomography(PET)revealed radiation necrosis. The last follow-up MRI 15 months after SRT showed no further recurrence. CONCLUSION: Astroblastoma is rare, therefore, no optimal management is known. SRT may be effective to treat recurrent astroblastomas. 11C-methionine PET/CT was useful to differentiate metastatic disease from radiation necrosis.

Vocal cord inflammatory myofibroblastic tumor with mucoid deposits harboring TIMP3-ALK fusion: A potential diagnostic pitfall.

A 35-year-old Japanese man who had experienced hoarseness for 10 years presented with a vocal cord lesion. A gross examination revealed a left vocal cord polyp occupying two-thirds of the vocal space. The endoscopically resected lesion contained scattered atypical fibroblastic, stellate, or ganglion-like cells with mucoid stroma. Vacuolated cells were also seen. Lymphoplasmacytic infiltrate was largely undetectable. A vocal cord polyp was first suspected, but well-differentiated liposarcoma and inflammatory myofibroblastic tumor (IMT) were included in the differential diagnoses. The tumor cells were positive for anaplastic lymphoma kinase (ALK), calponin, and vimentin, and negative for other smooth muscle markers by immunohistochemistry. Structures resembling myofibroblasts were not observed by electron microscopy, which confirmed abundant rough endoplasmic reticulum in the tumor cells and accumulated lipid droplets in some tumor cells. ALK gene rearrangement was detected by fluorescence in situ hybridization, and TIMP3-ALK fusion was confirmed by 5' rapid amplification of cDNA ends. We diagnosed the lesion as an IMT, and an ALK-rearranged stellate cell tumor may be postulated. This is the first report of a fusion partner gene of ALK in a case of laryngeal IMT.

Merkel cell polyomavirus and Langerhans cell neoplasm.

BACKGROUND: The relationship between various external agents such as pollen, food, and infectious agents and human sensitivity exists and is variable depending upon individual's health conditions. For example, we believe that the pathogenetic potential of the Merkel cell polyomavirus (MCPyV), the resident virus in skin, is variable and depends from the degree of individual's reactivity. MCPyV as well as Epstein-Barr virus, which are normally connected with humans under the form of subclinical infection, are thought to be involved at various degrees in several neoplastic and inflammatory diseases. In this review, we cover two types of Langerhans cell neoplasms, the Langerhans cell sarcoma (LCS) and Langerhans cell histiocytosis (LCH), represented as either neoplastic or inflammatory diseases caused by MCPyV. METHODS: We meta-analyzed both our previous analyses, composed of quantitative PCR for MCPyV-DNA, proteomics, immunohistochemistry which construct IL-17 endocrine model and interleukin-1 (IL-1) activation loop model, and other groups' data. RESULTS: We have shown that there were subgroups associated with the MCPyV as a causal agent in these two different neoplasms. Comparatively, LCS, distinct from the LCH, is a neoplastic lesion (or sarcoma) without presence of inflammatory granuloma frequently observed in the elderly. LCH is a proliferative disease of Langerhans-like abnormal cells which carry mutations of genes involved in the RAS/MAPK signaling pathway. We found that MCPyV may be involved in the development of LCH. CONCLUSION: We hypothesized that a subgroup of LCS developed according the same mechanism involved in Merkel cell carcinoma pathogenesis. We proposed LCH developed from an inflammatory process that was sustained due to gene mutations. We hypothesized that MCPyV infection triggered an IL-1 activation loop that lies beneath the pathogenesis of LCH and propose a new triple-factor model.

Hepatic stellate cells derived from the nestin-positive cells in septum transversum during rat liver development.

Hepatic stellate cells (HSCs) play a principal role in Vitamin A metabolism and are considered the major matrix-producing cell type in the diseased liver. Rat HSCs are identified by immunohistochemistry with myogenic or mesenchymal (desmin, vimentin, and alpha-smooth muscle actin) or neural (e.g., GFAP or neuronal cell adhesion molecule) markers. Embryonic origin of rat HSCs was determined using these markers. Nestin, an intermediate filament protein originally identified in neuronal stem or progenitor cells, is widely used as a stem cell marker, including hepatic stem cells in adult rat livers. Additionally, nestin is reportedly expressed in activated HSCs during liver injury and hepatic regeneration. However, little is known about nestin expression in rat fetal liver HSCs. The present study aimed to clarify nestin-positive HSC expression during rat liver development. At embryonic day (ED) 10.5, nestin expression in mesenchymal cells adjacent to the liver bud was detected by immunohistochemistry. At ED 11.5, nestin-positive cells were also detected in desmin-positive cells appearing and increasing in intensity by ED 16.5. However, nestin-positive cells in the parenchyma decreased by ED 20.5 or later. These findings reveal that the nestin-positive HSCs during rat liver development originate from nestin-positive mesenchymal cells in the septum transversum.

Questiomycin A stimulates sorafenib-induced cell death via suppression of glucose-regulated protein 78.

Hepatocellular carcinoma (HCC) is one of the most difficult cancers to treat owing to the lack of effective chemotherapeutic methods. Sorafenib, the first-line and only available treatment for HCC, extends patient overall survival by several months, with a response rate below 10%. Thus, the identification of an agent that enhances the anticancer effect of sorafenib is critical for the development of therapeutic options for HCC. Endoplasmic reticulum (ER) stress response is one of the methods of sorafenib-induced cell death. Here we report that questiomycin A suppresses expression of GRP78, a cell-protective ER chaperone protein. Analysis of the molecular mechanisms of questiomycin A revealed that this compound stimulated GRP78 protein degradation in an ER stress response-independent manner. Cotreatment with sorafenib and questiomycin A suppressed GRP78 protein expression, which is essential for the stimulation of sorafenib-induced cell death. Moreover, our in vivo study demonstrated that the coadministration of sorafenib and questiomycin A suppressed tumor formation in HCC-induced xenograft models. These results suggest that cotreatment with sorafenib and questiomycin A is a novel therapeutic strategy for HCC by enhancing sorafenib-dependent ER stress-induced cell death, and downregulation of GRP78 is a new target for the stimulation of the therapeutic effects of sorafenib in HCC.

Review of hereditary leiomyomatosis renal cell carcinoma with focus on clinical and pathobiological aspects of renal tumors.

The entity of hereditary leiomyomatosis renal cell carcinoma (HLRCC)-associated RCC has been proposed and integrated into the recent International Society of Urologic Pathology (ISUP) of renal tumors. This tumor is characterized by presence of cutaneous and/or uterine leiomyomas and RCC and autosomal dominant hereditary form. Grossly, HLRCC arising in the kidney show the solid tumor with frequent partial cystic area. Microscopically, the tumor typically shows papillary RCC, type 2, with eosinophilic large nucleoli reminiscent of cytomegaloviral inclusion and perinuclear clearing/haloes. Immunohistochemically, tumor cells show the overexpression for 2SC and reduced expression of FH. Germline mutation of fumarate hydratase (FH) gene, the HLRCC responsible gene mapped to chromosome 1q43, has been identified in patients with HLRCC. As the renal cancer in patients with HLRCC generally behave aggressively even in a small size, complete surgical resection and retroperitoneal lymph node resection should be performed promptly when the tumor is discovered. The surveillance of renal tumor in FH gene germline mutation-positive patients should be started from the early age using ultrasound sonography or magnetic resonance imaging.

Acute undifferentiated leukemia (stem cell acute leukemia) showing differentiation to Langerhans cell-like cells in lymph nodes.

A 75-year-old woman was referred to our hospital with suspected leukemia. Complete blood count demonstrated WBC 3,810/µl with 26% blasts, Hb of 11.7 g/dl and Plt of 18.0×104/µl. Bone marrow aspiration revealed blasts (86.3%) with expressions of CD34, CD7, TdT, CD33, and CD117. MPO was negative. Chromosomal analysis of the bone marrow showed isolated trisomy 10 in all leukemic cells (20/20). Swelling of superficial lymph nodes was also observed. Cervical lymph node biopsy revealed leukemic blasts which had the same phenotype as those in the bone marrow except that proliferation of Langerhans cell-like cells (LCs) was observed in the paracortex. LCs had pale cytoplasm and grooved nuclei, and were positive for both CD1a and S100 protein. Trisomy 10 was detected in both the leukemic blasts and the LCs by fluorescence in situ hybridization. This rare case strongly suggests leukemic cells to differentiate into LCs.

Acute-phase ITIH4 levels distinguish multi-system from single-system Langerhans cell histiocytosis via plasma peptidomics.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a proliferative disorder in which abnormal Langerhans cell (LC)-like cells (LCH cells) intermingle with inflammatory cells. Whether LCH is reactive or neoplastic remains a controversial matter. We recently described Merkel cell polyomavirus (MCPyV) as a possible causative agent of LCH and proposed interleukin-1 loop model: LCH is a reactive disorder with an underlying oncogenic potential and we now propose to test this theory by looking for acute markers of inflammation. We detected MCPyV-DNA in the peripheral blood cells of patients with high-risk organ-type (LCH-risk organ (RO) (+)) but not those with non-high-risk organ-type LCH (LCH-RO (-)); this difference was significant. LCH-RO (-) is further classified by its involvement of either a single organ system (SS-LCH) or multiple organ systems (MS-LCH). In patients with LCH-RO (-), MCPyV-DNA sequences were present in LCH tissues, and significant differences were observed between LCH tissues and control tissues associated with conditions such as dermatopathic lymphadenopathy and reactive lymphoid hyperplasia. Although MCPyV causes subclinical infection in nearly all people and 22 % of healthy adults will harbor MCPyV in their buffy coats, circulating monocytes could serve as MCPyV reservoirs and cause disseminated skin lesions. METHODS: Plasma sample from 12 patients with LCH-RO (-) (5 MS-LCH and 7 SS-LCH) and 5 non-LCH patients were analyzed by peptidomics. Mass spectrometry (MS) spectra were acquired and peptides exhibiting quantitative differences between MS-LCH and SS-LCH patients were targeted. RESULTS: One new candidate biomarker, m/z 3145 was selected and identified after obtaining a MS/MS fragmentation pattern using liquid chromatography-MS/MS. This peak was identified as a proteolytic fragment derived from inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4, [PDB: Q14624]). CONCLUSIONS: Peptidomics of LCH have revealed that the level of acute-phase ITIH4 distinguishes MS-LCH-RO (-) from SS-LCH-RO (-). Acute-phase proteins serve non-specific, physiological immune functions within the innate immune system. LCH may be a reactive disorder with both underlying neoplastic potential of antigen presenting cells harboring BRAF mutations and hyper-immunity of other inflammatory cells against MCPyV infection. Among LCH-RO (-), MCPyV-DNA sequences were present in both MS-LCH tissues and SS-LCH tissues without significant differences. ITIH4 may show that LCH activity or LCH subtypes correlates with the systemic or localized reactions of MCPyV infection.

Interleukin-1 loop model for pathogenesis of Langerhans cell histiocytosis.

We propose Langerhans cell histiocytosis (LCH) is an inflammatory process that is prolonged by mutations. We hypothesize that Merkel cell polyomavirus (MCPyV) infection triggers an interleukin-1 (IL-1) activation loop that underlies the pathogenesis of LCH. Langerhans cells (LCs) are antigen presenting cells in the skin. When LCs encounter exogenous antigens, they migrate from the epidermis into draining lymphoid tissues to initiate T-cell activity. It has been proposed that LC migration-related factors, including E-cadherin, matrix metalloproteinase, and Notch ligand induce LCH activity. We found that the tyrosine phosphatase SHP-1, which binds IL-1 receptor-associated kinase 1, is expressed at a significantly higher level in LCH affecting multiple organ systems (MS-LCH) than in LCH affecting a single organ system (SS-LCH). IL-1 stimulates T helper 17 cells and their signature cytokine IL-17 had been a matter of controversy. We detected higher levels of IL-17A receptor expression in MS-LCH than in SS-LCH and proposed an IL-17 endocrine model that could settle the controversy. IL-1 is the first cytokine secreted in response to sensitizers and promotes LC migration from sentinel tissues. Myeloid differentiation primary response 88 (MyD88), downstream of the IL-1 receptor, has functions in both RAS signaling and inflammation, leading to human cell transformation. In 2010, an activating mutation in the B-rapidly accelerated fibrosarcoma gene (BRAF) V600E was found in LCH. This BRAF mutation induces phosphorylation of the extracellular signal-regulated kinase (ERK) that may play an important role with MyD88 in LCH pathogenesis. However, phosphorylated ERK (pERK) is rapidly dephosphorylated by dual specificity phosphatase 6 (DUSP6), and limited proliferation is predicted in BRAF mutant cells. MyD88 binds pERK via its D-domain, thereby preventing pERK-DUSP6 interaction and maintaining ERK in an active, phosphorylated state. We detected MCPyV-DNA in the peripheral blood cells of two out of three patients with LCH in high-risk organs but not in those of patients with LCH in non-high-risk organs (0/12; P = .029). MCPyV infection can trigger precursor LCH cells with BRAF mutation to produce IL-1; the IL-1 loop is amplified in all LCH subclasses. Our model indicates both BRAF mutation and IL-1 loop regulation as potential therapeutic targets.

Phosphohistone-H3 (PHH3) is prognostic relevant in Merkel cell carcinomas but Merkel cell polyomavirus is a more powerful prognostic factor than AJCC clinical stage, PHH3, Ki-67 or mitotic indices.

Merkel cell carcinomas (MCCs) associated with Merkel cell polyomavirus (MCPyV) have better prognosis than those without MCPyV. The relationship between mitotic index (MI) and MCC outcome has remained elusive because of the difficulty in differentiating mitotic cells from apoptotic ones. We evaluated the role of phosphohistone-H3 (PHH3) (Ser10), a new mitotic count biomarker, in MCPyV-positive or -negative MCC patients, and assessed its prognostic value in comparison to Ki-67 labeling index or MI using hematoxylin and eosin (HE) staining. We compared the prognostic value of PHH3 mitotic index with that of MI by HE in 19 MCPyV-positive and 9 MCPyV-negative MCC patients. PHH3-positive immunoreactivity was mostly observed in mitotic figures. Multivariate analysis significantly showed that MCPyV status (HR, 0.004; 95% CI 0.0003-0.058) and the American Joint Committee of Cancer (AJCC) stage (HR, 5.02; 95% CI 1.23-20.51) were observed as significantly independent prognostic factors for OS. PHH3-positive cell counts/10 HPF was a slightly significant independent prognostic factor for OS (HR, 4.96; 95% CI 0.93-26.55). PHH3-positive MI and MCPyV status in MCC patients are useful in prognostication, although MCPyV-infection is a more powerful prognostic factor in MCCs than the AJCC scheme on proliferation or mitotic indices.

Merkel cell polyomavirus (MCPyV) strains in Japanese merkel cell carcinomas (MCC) are distinct from Caucasian type MCPyVs: genetic variability and phylogeny of MCPyV genomes obtained from Japanese MCPyV-infected MCCs.

Most of merkel cell carcinomas (MCC), a rare, aggressive skin cancer with neuroendocrine features, harbor merkel cell polyomavirus (MCPyV). Seroepidemiological studies suggested high prevalence of MCPyV in the human population. More than ten sequence data on MCPyV strains in Japan have been available, whereas most sequence data were detected from patients living in Europe or European ancestry. Analysis of nine almost complete and 19 partial sequences from two oncogenes, small T antigen (ST) and large T antigen (LT) genomes obtained from 32 Japanese MCPyV-infected MCC revealed that each Japanese MCPyV-infected MCC harbored a specific MCPyV strain with some synonymous or, silent mutations and stop codons or deletions, but functional domains of T antigen had no amino acid changes. All stop codons were localized after retinoblastoma protein-binding domain. These Japanese MCPyV strains were very closely interrelated to themselves and a consensus sequence of Japanese strain was generated. Phylogenetic analysis of our nine sequences and 70 other sequences for ST and LT gene registered in GenBank indicated that Japanese or Asian MCPyV strains formed distinct clades from Caucasian clade, and phylogenetic tree of our nine and 75 other sequences for ST gene formed characteristic three clades and showed that all Japanese or Asian strains were included in the dominant clade. These suggested the possibility of geographically related genotypes of MCPyV. The genomic characterization of MCPyV variants will provide an important database and insights for illuminating their evolutional and biological differences.