Blockade of histamine receptor H1 augments immune checkpoint therapy by enhancing MHC-I expression in pancreatic cancer cells.

BACKGROUND: Although immune checkpoint blockade (ICB) therapy has proven to be extremely effective at managing certain cancers, its efficacy in treating pancreatic ductal adenocarcinoma (PDAC) has been limited. Therefore, enhancing the effect of ICB could improve the prognosis of PDAC. In this study, we focused on the histamine receptor H1 (HRH1) and investigated its impact on ICB therapy for PDAC. METHODS: We assessed HRH1 expression in pancreatic cancer cell (PCC) specimens from PDAC patients through public data analysis and immunohistochemical (IHC) staining. The impact of HRH1 in PCCs was evaluated using HRH1 antagonists and small hairpin RNA (shRNA). Techniques including Western blot, flow cytometry, quantitative reverse transcription polymerase chain reaction (RT-PCR), and microarray analyses were performed to identify the relationships between HRH1 and major histocompatibility complex class I (MHC-I) expression in cancer cells. We combined HRH1 antagonism or knockdown with anti-programmed death receptor 1 (αPD-1) therapy in orthotopic models, employing IHC, immunofluorescence, and hematoxylin and eosin staining for assessment. RESULTS: HRH1 expression in cancer cells was negatively correlated with HLA-ABC expression, CD8+ T cells, and cytotoxic CD8+ T cells. Our findings indicate that HRH1 blockade upregulates MHC-I expression in PCCs via cholesterol biosynthesis signaling. In the orthotopic model, the combined inhibition of HRH1 and αPD-1 blockade enhanced cytotoxic CD8+ T cell penetration and efficacy, overcoming resistance to ICB therapy. CONCLUSIONS: HRH1 plays an immunosuppressive role in cancer cells. Consequently, HRH1 intervention may be a promising method to amplify the responsiveness of PDAC to immunotherapy.

Patient-derived organoids of pancreatic ductal adenocarcinoma for subtype determination and clinical outcome prediction.

BACKGROUND: Recently, two molecular subtypes of pancreatic ductal adenocarcinoma (PDAC) have been proposed: the "Classical" and "Basal-like" subtypes, with the former showing better clinical outcomes than the latter. However, the "molecular" classification has not been applied in real-world clinical practice. This study aimed to establish patient-derived organoids (PDOs) for PDAC and evaluate their application in subtype classification and clinical outcome prediction. METHODS: We utilized tumor samples acquired through endoscopic ultrasound-guided fine-needle biopsy and established a PDO library for subsequent use in morphological assessments, RNA-seq analyses, and in vitro drug response assays. We also conducted a prospective clinical study to evaluate whether analysis using PDOs can predict treatment response and prognosis. RESULTS: PDOs of PDAC were established at a high efficiency (> 70%) with at least 100,000 live cells. Morphologically, PDOs were classified as gland-like structures (GL type) and densely proliferating inside (DP type) less than 2 weeks after tissue sampling. RNA-seq analysis revealed that the "morphological" subtype (GL vs. DP) corresponded to the "molecular" subtype ("Classical" vs. "Basal-like"). The "morphological" classification predicted the clinical treatment response and prognosis; the median overall survival of patients with GL type was significantly longer than that with DP type (P < 0.005). The GL type showed a better response to gemcitabine than the DP type in vitro, whereas the drug response of the DP type was improved by the combination of ERK inhibitor and chloroquine. CONCLUSIONS: PDAC PDOs help in subtype determination and clinical outcome prediction, thereby facilitating the bench-to-bedside precision medicine for PDAC.

MicroRNA-20a in extracellular vesicles derived from duodenal fluid is a possible biomarker for pancreatic ductal adenocarcinoma.

Background: Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate owing to its late diagnosis and aggression. In addition, there are relatively few minimally invasive screening methods for the early detection of PDAC, making the identification of biomarkers for this disease a critical priority. Recent studies have reported that microRNAs in extracellular vesicles (EV-miRs) from bodily fluids can be useful for the diagnosis of PDACs. Given this, we designed this study to evaluate the utility of cancer EVs extracted from duodenal fluid (DF) and their resident EV-miRs as potential biomarkers for the detection of PDAC. Methods: EV-miRs were evaluated and identified in the supernatants of various pancreatic cancer cell lines (Panc-1, SUIT2, and MIAPaca2), human pancreatic duct epithelial cells, and the DF from patients with PDAC and healthy controls. EVs were extracted using ultracentrifugation and the relative expression of EV-miR-20a was quantified. Results: We collected a total of 34 DF samples (27 PDAC patients and seven controls) for evaluation and our data suggest that the relative expression levels of EV-miR-20a were significantly higher in patients with PDAC than in controls (p = 0.0025). In addition, EV-miR-20a expression could discriminate PDAC from control patients regardless of the location of the tumor with an area under the curve values of 0.88 and 0.88, respectively. Conclusions: We confirmed the presence of EVs in the DF and suggest that the expression of EV-miR-20a in these samples may act as a potential diagnostic biomarker for PDAC.

Two cases of pancreatic neuroendocrine tumors with ectopic ACTH syndrome during their disease course.

Pancreatic neuroendocrine tumors (PanNETs) are rare malignant tumors that occur in the pancreas. They are divided into functioning and non-functioning tumors based on the presence or absence of their specific hormonal hyper-expression symptoms. Adrenocorticotropic hormone (ACTH)-producing PanNETs are rare, functional tumors, and their clinical characteristics and outcomes have not been well reported.Here, we report the cases of two patients with PanNETs who presented with ectopic ACTH syndrome (EAS) during the course of their disease. Case 1 involved a non-functioning PanNET at the time of surgery. During treatment for recurrent liver metastases, the patient presented with EAS and tumor-associated hypercalcemia, probably due to ACTH and parathyroid hormone-related peptide (PTHrP) production from the liver tumor. Case 2 was a gastrinoma, and similar to Case 1, this patient presented with EAS during the treatment of recurrent liver metastases.It is not uncommon for patients with PanNETs to have multiple hormones and develop secondary hormone secretion during their disease course, although tumor phenotypes differ between primary and metastatic sites. In patients with functioning PanNETs, symptom control with anti-hormonal therapy is essential, in addition to anti-tumor therapy, especially for EAS, which is an endocrine emergency disease that requires prompt diagnosis and treatment.

Immature stroma and high infiltration of CD15+ cells are predictive markers of poor prognosis in different subsets of patients with pancreatic cancer.

Preoperative treatment is commonly carried out for borderline resectable pancreatic ductal adenocarcinoma (PDAC). However, the relationship between the combination of immune cells in the tumor microenvironment and their intratumoral heterogeneity along with their association with histological findings remains unclear, especially in patients receiving preoperative chemotherapy. We aimed to explore the therapeutic strategies for patients with PDAC with poor prognosis after receiving chemotherapy based on histological and immunological microenvironmental classifications. We investigated the correlation between the prognosis and histological immune microenvironmental factors of patients who initially underwent surgery (n = 100) and were receiving gemcitabine plus nab-paclitaxel (GEM + nabPTX) as preoperative chemotherapy (n = 103). Immune profiles were generated based on immune cell infiltration into the tumor, and their correlation with patient outcomes and histological features was analyzed. Tumor-infiltrating neutrophils (TINs) were identified as independent poor prognostic factors using multivariate analysis in both surgery-first and preoperative chemotherapy groups. The patients were further classified into four groups based on immune cell infiltration into the tumor. Patients with high CD15 infiltration into the tumor and immature stroma at the cancer margins showed the worst prognosis in the preoperative chemotherapy group. The analysis of mRNA expression and immunohistochemical features revealed that CXCR2, the receptor for CXCL8, was correlated with disease-free and overall survival. We inferred that patients with immature stroma at the margins and high infiltration of CD15+ neutrophils within the tumor showed the worst prognosis and they could particularly benefit from treatment with inhibitors targeting CXCR2 or CXCL8.

The chaperone protein GRP78 released from MPN cells increases the expression of lysyl oxidase in a human stromal cell line.

Impaired function of the endoplasmic stress (ER) response causes numerous pathological conditions, including tissue fibrosis. In the present study, we aimed to determine the pathological role of ER stress response systems in myeloproliferative neoplasms (MPNs). We found increased expression of the chaperone protein glucose-regulated protein (GRP) 78, a central regulator of ER stress, in megakaryocytes from primary myelofibrosis or postessential thrombocythemia myelofibrosis patients. GRP78 was overexpressed in JAK2V617F-harboring cell lines; however, inhibitors of ER stress did not affect the expression levels of GRP78. In contrast, ruxolitinib, a well-known inhibitor of JAK2V617F, clearly blocked GRP78 expression in these cells through downregulation of transcription factor 4 (ATF4). Interestingly, GRP78 was secreted from HEL and SET-2 cells into culture media. Coculture of these cells with HS-5 cells, a human bone marrow stroma-derived cell line, induced enhanced expression of lysyl oxidase (LOX), which mediates cross-linking of collagen fibers and induces tissue fibrosis, in HS-5 cells. An anti-GRP78 neutralizing antibody abrogated LOX elevation; in contrast, recombinant GRP78 protein induced LOX protein expression in HS-5 cells. Our observations suggest that the oncogenic protein JAK2V617F induces overexpression and release of GRP78, which may induce a fibrotic phenotype in surrounding bone marrow stromal cells.

Pre-exposure prophylaxis with tixagevimab/cilgavimab for coronavirus disease 2019 (COVID-19) during the Omicron BA.5 wave at a single institution in Japan.

Pre-exposure prophylaxis with tixagevimab/cilgavimab was considered a useful strategy to protect immunocompromised patients from COVID-19 based on the phase 3 PROVENT trial conducted between November 2020 and March 2021. However, after late 2021, the dominant substrains of COVID-19 changed to Omicron substrains, which showed resistance to tixagevimab/cilgavimab. Therefore, it is important to re-evaluate the real-world efficacy of tixagevimab/cilgavimab for the prevention of COVID-19 in the Omicron era. To this end, we retrospectively evaluated the efficacy and safety of tixagevimab/cilgavimab prophylaxis for COVID-19 during the Omicron BA.5 wave in Japan. A total of 240 consecutive patients with hematologic malignancies received tixagevimab/cilgavimab at our institution from October 18, 2022, to January 31, 2023. Among them, the cumulative incidence of COVID-19 at 90 days was 6.4%. A total of 10/14 (71.4%) had mild infection, and 4/14 (28.5%) had severe infection. No patient died due to COVID-19. Adverse events consisted of deep vein thrombosis in 2 patients. Our analysis indicated that pre-exposure prophylaxis with tixagevimab/cilgavimab might have clinical effectiveness in reducing the severity of COVID-19 in Japanese HM patients, even in the Omicron BA.5 surge. It also suggested that tixagevimab/cilgavimab may be associated with cardiovascular complications.

Eyestalk transcriptome and methyl farnesoate titers provide insight into the physiological changes in the male snow crab, Chionoecetes opilio, after its terminal molt.

The snow crab, Chionoecetes opilio, is a giant deep-sea brachyuran. While several decapod crustaceans generally continue to molt and grow throughout their lifetime, the snow crab has a fixed number of molts. Adolescent males continue to molt proportionately to their previous size until the terminal molt at which time an allometric increase in chela size occurs and an alteration of behavioral activities occurs, ensuring breeding success. In this study, we investigated the circulating concentrations of methyl farnesoate (an innate juvenile hormone in decapods) (MF) before or after the terminal molt in males. We then conducted eyestalk RNAseq to obtain molecular insight into the regulation of physiological changes after the terminal molt. Our analyses revealed an increase in MF titers after the terminal molt. This MF surge may be caused by suppression of the genes that encode MF-degrading enzymes and mandibular organ-inhibiting hormone that negatively regulates MF biosynthesis. Moreover, our data suggests that behavioral changes after the terminal molt may be driven by the activation of biogenic amine-related pathways. These results are important not only for elucidating the physiological functions of MFs in decapod crustaceans, which are still largely unknown, but also for understanding the reproductive biology of the snow crab.

Clinicopathologic Features and Genetic Alterations in Mixed-Type Ampullary Carcinoma.

Mixed-type ampullary carcinoma is a subtype that combines intestinal-type (I-type) and pancreatobiliary-type (PB-type) lesions, but few studies have examined its clinicopathologic features and genetic alterations. The differences in genetic alterations between mixed type and other subtypes, as well as the genetic differences between I-type and PB-type lesions in the mixed type, remain unclear. In this study, we compared the clinicopathologic features and prognosis of 110 ampullary carcinomas classified by hematoxylin and eosin and immunohistochemical staining as follows: 63 PB-type, 35 I-type, and 12 mixed-type carcinomas. A comparative analysis of genetic mutations by targeted sequencing of 24 genes was also performed in 3 I-type cases, 9 PB-type cases, and I and PB-type lesions of 6 mixed-type cases. The mixed subtype had a poorer prognosis than the other subtypes, and there was also a similar tendency in the adjuvant group (n = 22). A total of 49 genetic mutations were detected in all 18 lesions for which genetic alteration was analyzed. No genetic mutations specific to the mixed type were found, and it was not possible to determine genetically whether the mixed type had originally been I or PB type. However, 5 of 6 cases had mutations common to both I and PB-type lesions, and additional mutations were found only in either I or PB-type lesions. In support of this, the mixed type more frequently exhibited genetic heterogeneity intratumorally than the other subtypes. Mixed-type tumors are histologically, immunohistochemically, and genetically heterogeneous, and this heterogeneity is associated with poor prognosis and may affect treatment resistance.

Extracellular volume fraction determined by dual-layer spectral detector CT: Possible role in predicting the efficacy of preoperative neoadjuvant chemotherapy in pancreatic ductal adenocarcinoma.

PURPOSE: To clarify the relationship between extracellular volume (ECV) measured by dual-energy CT (DECT) and efficacy of preoperative neoadjuvant chemotherapy (NAC) in patients with pancreatic ductal adenocarcinoma (PDAC), as compared with single-energy CT (SECT). METHODS: We enrolled 67 patients with PDAC who underwent dynamic contrast-enhanced CT with a dual-energy CT system prior to NAC. Attenuation values were measured on unenhanced and the equilibrium-phase 120-kVp equivalent CT images for PDAC and the aorta. ΔHU-tumor, ΔHU-tumor/ΔHU-aorta, and SECT-ECV were calculated. Iodine densities of the tumor and aorta were measured in the equilibrium phase, and DECT-ECV of the tumor was calculated. Response to NAC was evaluated and the correlation between imaging parameters and response to NAC was statistically assessed. RESULTS: Tumor DECT-ECVs were significantly lower in the response group (n = 7) than in the non-response group (n = 60), with most significant difference (p = 0.0104). DECT-ECV showed highest diagnostic value with an Az value of 0.798. When using the optimal cut off value of DECT-ECV (<26.0 %), sensitivity, specificity, accuracy, positive predictive value, and negative value for predicting response group were 71.4 %, 85.0 %, 83.6 %, 35.7 % and 96.2 %, respectively. CONCLUSION: PDAC with lower DECT-ECV can potentially show better response to NAC. DECT-ECV might be a useful biomarker for predicting response to NAC in patients with PDAC.

[Hypokalemia and potassium replacement therapy in allogeneic hematopoietic stem cell transplantation].

Hypokalemia is common in allogeneic hematopoietic stem cell transplantation (allo-HCT) patients and is associated with non-relapse mortality (NRM). Therefore, it is extremely important to replace potassium adequately. We evaluated the safety and efficacy of potassium replacement therapy by retrospectively analyzing the incidence and severity of hypokalemia in 75 patients who received allo-HCT at our institution. 75% of patients developed hypokalemia during the allo-HSCT, and 44% of patients had grade 3-4 levels of hypokalemia. NRM was significantly higher in patients with grade 3-4 hypokalemia than in patients without severe hypokalemia (one-year NRM: 30% vs 7%, p=0.008). Although 75% of the patients required potassium replacement that exceeded the range of potassium chloride solutions package inserts in Japan, we did not experience any adverse events associated with hyperkalemia. Our current observations suggested that the Japanese package insert for potassium solution injection should be revised for potassium needs.

Prognostic value of nuclear morphometry in myxoid liposarcoma.

Myxoid liposarcoma (MLS) accounts for 20%-30% of liposarcoma and the round cell component (RCC) is believed to be a specific poor prognostic factor. However, the RCC assessment criteria are vaguely defined and, therefore, are inconsistently employed by pathologists. In this study, we modified and applied two established grading systems to evaluate nuclear atypia (namely, the World Health Organization/International Society of Urological Pathology and the Fuhrman grading in renal cell carcinoma) in 64 MLS cases. Detailed software-based assessments of the morphology and the cellularity were performed. DNA mutation analysis, comprehensive mRNA expression analysis, and immunohistochemistry were also performed. Our findings revealed that the high-nuclear-grade group according to the modified Fuhrman grading system exhibited a significantly poor disease-free survival (hazard ratio: 4.43; 95% confidence interval: 0.9-22.6; p = 0.047). On the other hand, the cellularity was significantly higher in the modified Fuhrman high-grade group (p = 0.010 at the percentage of the hypercellular area; p = 0.003 at the maximum cell density) but did not qualify per se as a poor prognostic factor in the survival analyses. Furthermore, the modified Fuhrman high-grade group significantly expressed the cell cycle-related genes (such as FOXM1, PLK1, and CDK1). In conclusion, our analyses suggest that an evaluation focusing on nuclear morphology (rather than on cellular density) can be more reliable in predicting the MLS prognosis.

Ampullary Neuroendocrine Neoplasm: Clinicopathological Characteristics and Novel Endoscopic Entity.

BACKGROUND: Neuroendocrine neoplasms of the ampulla of Vater (ampullary NEN) have features of both gastrointestinal and pancreato-biliary (PB) NEN. However, the limited number of studies examining ampullary NEN makes it difficult to clarify their unique characteristics. This study aimed to elucidate the clinical characteristics of ampullary NEN. METHODS: We enrolled 162 patients with PB-NEN diagnosed at Kyushu University Hospital between 2011 and 2020. Clinical features, pathological diagnoses, treatments, and prognoses were retrospectively analyzed. We also compared ampullary NEN with pancreatic NEN (PanNEN). RESULTS: We analyzed 10 ampullary NEN cases and 149 PanNEN cases. The ampullary NEN cases consisted of 4 cases of neuroendocrine tumor Grade 1 (NET G1), 1 NET G2 (Grade 2), and 5 neuroendocrine carcinomas (NECs). The incidences of NEC and cholangitis were significantly higher in ampullary NEN than in PanNEN. All ampullary NETs had a submucosal tumor-like appearance, as identified by endoscopic ultrasound-guided fine needle aspiration. We treated small NET G1 (<10 mm) with endoscopic papillectomy and large NET G1 with pancreaticoduodenectomy. There were no cases of recurrence after resection. All ampullary NECs presented with the characteristic endoscopic finding of a "crater sign" similar to deep-mining ulcers seen in gastric malignant lymphoma. Four cases underwent surgical resection, and 1 case was unresectable. Two patients who underwent multidisciplinary treatment were maintained without recurrence for over 2 years. CONCLUSIONS: Endoscopic findings showed identifiable distinctions between ampullary NETs and NECs.

Interhospital transmission of vancomycin-resistant Enterococcus faecium in Aomori, Japan.

BACKGROUND: Spread of vancomycin-resistant Enterococcus (VRE) is a global concern as a significant cause of healthcare-associated infections. A series of VRE faecium (VREf) outbreaks caused by clonal propagation due to interhospital transmission occurred in six general hospitals in Aomori prefecture, Japan. METHODS: The number of patients with VREf was obtained from thirty seven hospitals participating in the local network of Aomori prefecture. Thirteen hospitals performed active screening tests for VRE. Whole genome sequencing analysis was performed. RESULTS: The total number of cases with VREf amounted to 500 in fourteen hospitals in Aomori from Jan 2018 to April 2021. It took more than three years for the frequency of detection of VRE to return to pre-outbreak levels. The duration and size of outbreaks differed between hospitals according to the countermeasures available at each hospital. Whole genome sequencing analysis indicated vanA-type VREf ST1421 for most samples from six hospitals. CONCLUSIONS: This was the first multi-jurisdictional outbreak of VREf sequence type 1421 in Japan. In addition to strict infection control measures, continuous monitoring of VRE detection in local medical regions and smooth and immediate communication among hospitals are required to prevent VREf outbreaks.

Presence of bone marrow fibrosis in multiple myeloma may predict extramedullary disease.

We analyzed the incidence of bone marrow fibrosis in 91 newly diagnosed Japanese multiple myeloma (MM) patients and evaluated the impact of fibrosis on clinical characteristics and therapeutic outcomes. Thirty-four (37%) patients had greater than grade 1 bone marrow fibrosis. The presence of bone marrow fibrosis did not affect laboratory data, the percentage of plasma cells in bone marrow or cytogenetic findings. It also had no significant effect on response to initial treatment, engraftment after autologous hematopoietic stem cell transplantation or overall survival. Interestingly, the incidence of extramedullary disease at diagnosis was significantly higher in patients with bone marrow fibrosis (p = 0.006). Analysis of biological characteristics of MM cells revealed that expression of CD49e, an alpha5/beta1 integrin, was downregulated in MM cells derived from patients with bone marrow fibrosis (p = 0.026). When seven of the original 34 patients were re-evaluated for fibrosis grading after treatment, five (71%) showed a reduction in fibrosis. Our present findings suggest that the presence of bone marrow fibrosis may predict development of extramedullary disease in MM.

Myxoid type and non-myxoid type of intimal sarcoma in large vessels and heart: review of histological and genetic profiles of 20 cases.

Intimal sarcoma is one of the most common and well-known primary malignant neoplasms of the aorta and heart. The authors reviewed cases of intimal sarcoma from histological, immunohistochemical and genetic perspectives. Twenty cases of intimal sarcoma were retrieved. Immunohistochemistry and FISH of MDM2 and PDGFRA genes were performed. All 20 tumours were composed of spindle-shaped, stellate, oval or polygonal tumour cells with irregular hyperchromatic nuclei arranged in a haphazard pattern, accompanied by nuclear pleomorphism and frequent mitotic figures. Other histological findings were as follows: abnormal mitosis in 10 cases (50%), necrosis in 15 cases (75%), myxoid stroma in 12 cases (60%), cartilaginous formation in 1 case (5%), haemorrhage in 12 cases (60%) and fibrinous deposition in 14 cases (70%). The tumours were positive for MDM2 in 16 cases (80%), ERG in 4 cases (20%), alpha-smooth muscle actin in 6 cases (30%), desmin in 5 cases (25%) and AE1/AE3 in 4 cases (20%). Immunohistochemical positivity was focal in each case. Loss of H3K27me3 expression was noted in 2 cases (10%). MDM2 and PDGFRA gene amplifications were detected in 11 cases (55%) and 1 case (5%), respectively. Fisher's exact test revealed a significant correlation between MDM2 gene amplification and myxoid stroma (p = 0.0194). No parameters showed any association with the anatomical location of the tumours. It was suggested that myxoid histology of intimal sarcoma may be associated with MDM2 gene amplification and that intimal sarcoma may be divided into myxoid and non-myxoid types.

RNF43 as a predictor of malignant transformation of pancreatic mucinous cystic neoplasm.

Mucinous cystic neoplasm (MCN) of the pancreas rarely progresses to invasive carcinoma, but few studies have analyzed genomic alterations involved in its malignant transformation. The relationships of ring finger protein 43 (RNF43) mutations with cytological atypia, RNF43 protein expression, and Wnt signaling proteins in MCN remain unclear. This study included 106 MCN cases, classified into 89 low-grade dysplasia (LG), 9 high-grade dysplasia (HG), and 8 invasive carcinoma (INV). We analyzed HG/INV and LG lesions of 9 HG/INV cases and LG lesions of 9 LG cases using targeted sequencing and confirmed the protein expression of RNF43 and ß-catenin. The frequency of RNF43 mutations was significantly higher in HG/INV cases than in LG cases. Furthermore, HG/INV lesions (56%) and LG lesions (33%) of HG/INV cases possessed RNF43 mutation, whereas no such mutation was detected in any LG cases. The expression of RNF43 was reduced in 71% of HG/INV cases and significantly correlated with histological grade and aberrant expression of ß-catenin. In 3 of 5 RNF43-mutated cases, the expression of RNF43 was reduced, but there was no significant correlation between RNF43 mutation and protein expression. MCNs frequently harbored KRAS mutations, at rates of 100% in HG/INV lesions and 50% in LG lesions of HG/INV and LG cases. There was no significant difference in mutation frequency in LG lesions between HG/INV and LG cases. These results suggest that RNF43 mutations may be involved in and predictive of malignant transformation from an early stage of MCN.

Transdifferentiation of mantle cell lymphoma into sarcoma with limited neuromuscular differentiation after conventional chemotherapy.

We report an exceptionally rare case of mantle cell lymphoma (MCL) that transdifferentiated into sarcoma with limited neuromuscular differentiation. An 81-year-old man with t(11;14)-positive MCL was treated with rituximab and bendamustine and achieved complete remission; however, just 2 months later, the patient developed multiple systemic tumors. Pathologic studies revealed round cell sarcoma expressing synaptophysin, CD56, and myogenin without any B-cell markers. The CCND1 translocation and an identical IGL gene rearrangement were shared by both the MCL and sarcoma. Whole-exome sequencing detected 189 single nucleotide variants (SNVs) in the MCL and 205 SNVs in the sarcoma; 160 SNVs including NSD2, ATM, RB1, and TP53 mutations were shared between MCL and sarcoma cells. An additional PTPN11 mutation was specifically found in the sarcoma. These findings confirmed the shared clonal origin of MCL and sarcoma in this patient and indicated that MCL can transdifferentiate into sarcoma in rare cases.

Histological and immunohistochemical features and genetic alterations in the malignant progression of giant cell tumor of bone: a possible association with TP53 mutation and loss of H3K27 trimethylation.

In rare cases, giant cell tumor of bone (GCTB) can undergo primary or secondary malignant transformation to malignant giant cell tumor of bone (MGCTB), but the details of the molecular alterations are still unclear. The present study aimed to elucidate the clinicopathologic and molecular features of MGCTBs based on immunohistochemistry, fluorescence in situ hybridization (FISH) and next generation sequencing (NGS) of nine MGCTBs (five primary and four secondary). Seven (78%) of 9 MGCTBs were immunohistochemically positive for H3.3 G34W. In two (22%) patients, although GCTB components were focally or diffusely positive for H3.3 G34W, their malignant components were entirely negative for H3.3 G34W, which was associated with heterozygous loss of H3F3A by FISH. NGS on four MGCTBs revealed pathogenic mutations in TP53 (n = 3), EZH2 (n = 1) and several other genes. Immunohistochemical analysis of the nine MGCTBs confirmed the p53 nuclear accumulation (n = 5) and loss of H3K27me3 expression (n = 3) and showed that they were mutually exclusive. In addition, four (80%) of five cases of pleomorphic or epithelioid cell-predominant MGCTBs were positive for p53, while three (75%) of four cases of spindle cell-predominant MGCTBs were negative for trimethylation at lysine 27 of histone 3 (H3K27me3). The results suggested that p53 alteration and dysfunction of histone methylation as evidenced by H3K27me3 loss may play an important role in the malignant progression of GCTB, and might contribute to the phenotype-genotype correlation in MGCTB. The combined histologic, immunohistochemical and molecular information may be helpful in part for the diagnosis of challenging cases.

Relationship between cellular morphology and abnormality of SWI/SNF complex subunits in pancreatic undifferentiated carcinoma.

PURPOSE: Pancreatic undifferentiated carcinoma (UDC) is a rare tumor with a worse prognosis than pancreatic ductal adenocarcinoma (PDAC). Recent study showed that UDC exhibits loss of SMARCB1, which is one of the subunits of the SWI/SNF complex. However, whether there are abnormalities of other SWI/SNF complex subunits in UDC has remained unknown. In this study, we attempted to clarify whether the loss of SWI/SNF complex subunits is related to the pathogenesis of UDC by comparing undifferentiated component (UC) and ductal adenocarcinoma component (DAC). METHODS: Genetic analysis of the ten UCs and six DACs was performed. The expression of ARID1A, SMARCA2, SMARCA4, SMARCB1, SMARCC1, and SMARCC2 in formalin-fixed, paraffin-embedded tumor tissues collected by surgical resection from 18 UDC patients was evaluated immunohistochemically. Moreover, two pancreatic cell lines were evaluated for the effects of siARID1A on the mRNA and protein expression of E-cadherin, vimentin, and epithelial-mesenchymal transition (EMT)-related markers by qRT-PCR, western blotting, and immunofluorescence staining. RESULTS: UCs tended to have a higher frequency of mutation in ARID1A, SMARCA4, and SMARCC2 than DACs. Immunohistochemically, UCs revealed reduced/lost expression of ARID1A (72%), SMARCB1 (44%), SMARCC1 (31%), and SMARCC2 (67%). Reduced/lost expression of ARID1A, SMARCB1, and SMARCC2 was significantly more frequently observed in UCs than in DACs. In the pancreatic cell lines, western blotting and qRT-PCR showed that the downregulation of ARID1A increased the expression of vimentin and EMT-related markers. CONCLUSION: Our results suggest that the abnormality of SWI/SNF complex subunits, especially ARID1A, is one of the factors behind the morphological change of UDC.