A case of pancreatic PEComa with prominent inflammatory cell infiltration: the inflammatory subtype is a distinct histologic group of PEComa.

BACKGROUND: PEComa is a mesenchymal tumor that can occur in various organs including the uterus and soft tissues. PEComas are composed of perivascular epithelioid cells, and angiomyolipoma (AML), clear cell sugar tumor (CCST), and lymphangiomyomatosis (LAM) are considered lesions of the same lineage as tumors of the PEComa family. Histologically, a common PEComa shows solid or sheet-like proliferation of epithelioid cells. This is accompanied by an increase in the number of dilated blood vessels. Here, we report a case of pancreatic PEComa with marked inflammatory cell infiltration. CASE PRESENTATION: A 74-year-old male patient underwent an appendectomy for acute appendicitis. Postoperative computed tomography and magnetic resonance imaging revealed a 30 × 25 mm non-contrast-enhanced circular lesion in the tail of the pancreas. The imaging findings were consistent with a malignant tumor, and distal pancreatectomy was performed. Histologically, most area of the lesion was infiltrated with inflammatory cells. A few epithelioid cells with large, round nuclei, distinct nucleoli, and eosinophilic granular cytoplasm were observed. Spindle-shaped tumor cells were observed. Delicate and dilated blood vessels were observed around the tumor cells. Immunohistochemically, the atypical cells were positive for αSMA, Melan A, HMB-45, and TFE3. The cytological characteristics of the tumor cells and the results of immunohistochemical staining led to a diagnosis of pancreatic PEComa. CONCLUSIONS: A histological variant known as the inflammatory subtype has been defined for hepatic AML. A small number of tumor cells present with marked inflammatory cell infiltration, accounting for more than half of the lesions, and an inflammatory myofibroblastic tumor-like appearance. To our knowledge, this is the first report of pancreatic PEComa with severe inflammation. PEComa is also a generic term for tumors derived from perivascular epithelioid cells, such as AML, CCST, and LAM. Thus, this case is considered an inflammatory subtype of PEComa. It has a distinctive morphology that is not typical of PEComa. This histological phenotype should be widely recognized.

Research autopsy programmes in oncology: shared experience from 14 centres across the world.

While there is a great clinical need to understand the biology of metastatic cancer in order to treat it more effectively, research is hampered by limited sample availability. Research autopsy programmes can crucially advance the field through synchronous, extensive, and high-volume sample collection. However, it remains an underused strategy in translational research. Via an extensive questionnaire, we collected information on the study design, enrolment strategy, study conduct, sample and data management, and challenges and opportunities of research autopsy programmes in oncology worldwide. Fourteen programmes participated in this study. Eight programmes operated 24 h/7 days, resulting in a lower median postmortem interval (time between death and start of the autopsy, 4 h) compared with those operating during working hours (9 h). Most programmes (n = 10) succeeded in collecting all samples within a median of 12 h after death. A large number of tumour sites were sampled during each autopsy (median 15.5 per patient). The median number of samples collected per patient was 58, including different processing methods for tumour samples but also non-tumour tissues and liquid biopsies. Unique biological insights derived from these samples included metastatic progression, treatment resistance, disease heterogeneity, tumour dormancy, interactions with the tumour micro-environment, and tumour representation in liquid biopsies. Tumour patient-derived xenograft (PDX) or organoid (PDO) models were additionally established, allowing for drug discovery and treatment sensitivity assays. Apart from the opportunities and achievements, we also present the challenges related with postmortem sample collections and strategies to overcome them, based on the shared experience of these 14 programmes. Through this work, we hope to increase the transparency of postmortem tissue donation, to encourage and aid the creation of new programmes, and to foster collaborations on these unique sample collections. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Identification of uromodulin deposition in the stroma of perinephric fibromyxoid nephrogenic adenoma by mass spectrometry.

Nephrogenic adenoma (NA) is an epithelial lesion that usually occurs in the mucosa of the urinary tract. Rare cases of deep infiltrative or perinephric lesions have also been reported. Recently, NA with characteristic fibromyxoid stroma (fibromyxoid NA) has been proposed as a distinct variant. Although shedding of distal renal tubular cells due to urinary tract rupture has been postulated as the cause of NA in general, the mechanism underlying extraurinary presentation of NA and fibromyxoid stromal change in fibromyxoid NA remains unknown. In this study, we performed mass spectrometry (MS) analysis in a case of perinephric fibromyxoid NA of an 82-year-old man who underwent right nephroureterectomy for distal ureteral cancer. The patient had no prior history of urinary tract injury or radiation. Periodic acid-Schiff staining-positive eosinophilic structureless deposits in the stroma of fibromyxoid NA were microdissected and subjected to liquid chromatography/MS. The analysis revealed the presence of a substantial amount of uromodulin (Tamm-Horsfall protein). The presence of urinary content in the stroma of perinephric fibromyxoid NA suggests that urinary tract rupture and engraftment of renal tubular epithelial cells directly cause the lesion.

Exosomes secreted by ST3GAL5high cancer cells promote peritoneal dissemination by establishing a premetastatic microenvironment.

Peritoneal dissemination of cancer affects patient survival. The behavior of peritoneal mesothelial cells (PMCs) and immune cells influences the establishment of a microenvironment that promotes cancer cell metastasis in the peritoneum. Here, we investigated the roles of lactosylceramide alpha-2,3-sialyltransferase (ST3G5; also known as ST3GAL5 and GM3 synthase) in the exosome-mediated premetastatic niche in peritoneal milky spots (MSs). Exosomes secreted from ST3G5high cancer cells (ST3G5high -cExos) were found to contain high levels of hypoxia-inducible factor 1-alpha (HIF1α) and accumulated in MSs via uptake in macrophages (MΦs) owing to increased expression of sialic acid-binding Ig-like lectin 1 (CD169; also known as SIGLEC1). ST3G5high -cExos induced pro-inflammatory cytokines and glucose metabolic changes in MΦs, and the interaction of these MΦs with PMCs promoted mesothelial-mesenchymal transition (MMT) in PMCs, thereby generating αSMA+ myofibroblasts. ST3G5high -cExos also increased the expression of immune checkpoint molecules and T-cell exhaustion in MSs, which accelerated metastasis to the omentum. These events were prevented following ST3G5 depletion in cancer cells. Mechanistically, ST3G5high -cExos upregulated chemokines, including CC-chemokine ligand 5 (CCL5), in recipient MΦs and dendritic cells (DCs), which induced MMT and immunosuppression via activation of signal transducer and activator of transcription 3 (STAT3). Maraviroc, a C-C chemokine receptor type 5 (CCR5) antagonist, prevented ST3G5high -cExo-mediated MMT, T-cell suppression, and metastasis in MSs. Our results suggest ST3G5 as a suitable therapeutic target for preventing cExo-mediated peritoneal dissemination.

[Case of Mixed Neuroendocrine-Non-Neuroendocrine Neoplasm of the Papilla of Vater Metastasizing to the Lung after Resection].

A 79-year-old man visited a hospital for right upper abdominal pain and nausea. After conservative treatment for cholangitis and pancreatitis owing to a pancreatic head lesion, he was referred to our hospital for further evaluation and treatment of the lesion. He was diagnosed with pancreatic head cancer or carcinoma of papilla of Vater and underwent subtotal stomach- preserving pancreaticoduodenectomy. Postoperative histopathological examination revealed the coexistence of adenocarcinoma( 60%)and neuroendocrine carcinoma(40%)components, consistent with the diagnosis of mixed neuroendocrine- non-neuroendocrine neoplasm(MiNEN). In addition, regional lymph node metastasis of the adenocarcinoma component was found. Adjuvant chemotherapy was not administered because of a poor performance status. Lung metastasis occurred 13 months after surgery. Chemotherapy with S-1 was administered, and partial response was obtained 17 months after surgery. Herein, we report this rare case of MiNEN of the papilla of Vater with lung metastasis.

CCDC85A is regulated by miR-224-3p and augments cancer cell resistance to endoplasmic reticulum stress.

MicroRNAs (miRNAs) play pivotal roles in the tumor microenvironment. Here, we analyzed miRNAs in tumor stromal fibroblasts. Expression of miR-224-3p in cancer-associated fibroblasts (CAF) from scirrhous gastric cancer patients was lower than in normal fibroblasts (NF). Introduction of a miR-224-3p mimic attenuated migration and invasion of CAF. Coiled-coil domain containing 85A (CCDC85A), whose function in tumors is not understood, was the target gene of miR-224-3p. Immunohistological analysis revealed that CCDC85A is expressed to varying degrees by cancer cells and CAFs in gastric and pancreatic carcinomas. Downregulation of CCDC85A in cancer cells revealed that these cells are vulnerable to endoplasmic reticulum (ER) stress induced by thapsigargin or tunicamycin, which were ameliorated after addback of CCDC85A. Injection of NF-derived exosomes containing miR-224-3p into the xenograft tumor increased tumor shrinkage by cisplatin treatment. Mechanistically, CCDC85A associated with the molecular chaperone GRP78 and GRP94, thereby inhibiting association of these negative regulators of the unfolded protein response (UPR), leading to sustained activation of PERK and downstream eIF2〈 and ATF4 upon ER stress. These data suggest a novel miR-224-3p-mediated function for CCDC85A: protection from ER stress and cisplatin resistance.

Macrophage numbers in the marginal area of sarcomas predict clinical prognosis.

Even when treated comprehensively by surgery, chemotherapy, and radiotherapy, soft-tissue sarcoma has an unfavorable outcome. Because soft-tissue sarcoma is rare, it is the subject of fewer clinicopathological studies, which are important for clarifying pathophysiology. Here, we examined tumor-associated macrophages in the intratumoral and marginal areas of sarcomas to increase our knowledge about the pathophysiology. Seventy-five sarcoma specimens (not limited to a single histological type), resected at our institution, were collected, and the number of CD68-, CD163-, and CD204-positive macrophages in the intratumoral and marginal areas was counted. We then performed statistical analysis to examine links between macrophage numbers, clinical factors, and outcomes. A high number of macrophages positive for all markers in both areas was associated with worse disease-free survival (DFS). Next, we divided cases according to the FNCLCC classification (Grade 1 and Grades 2/3). In the Grade 1 group, there was no significant association between macrophage number and DFS. However, in the Grade 2/3 group, high numbers of CD163- and CD204-positive macrophages in the marginal area were associated with poor DFS. By contrast, there was no significant difference between the groups with respect to high or low numbers of CD68-, CD163-, or CD204-positive macrophages in the intratumoral area. Multivariate analysis identified the number of CD163- and CD204-positive macrophages in the marginal area as an independent prognostic factor. Macrophage numbers in the marginal area of soft-tissue sarcoma may better reflect clinical behavior.

A New Chemotactic Mechanism Governs Long-Range Angiogenesis Induced by Patching an Arterial Graft into a Vein.

Chemotaxis, the migration of cells in response to chemical stimulus, is an important concept in the angiogenesis model. In most angiogenesis models, chemotaxis is defined as the migration of a sprout tip in response to the upgradient of the VEGF (vascular endothelial growth factor). However, we found that angiogenesis induced by performing arterial patch grafting on rabbits occurred under the decreasing VEGFA gradient. Data show that the VEGFA concentration peaked at approximately 0.3 to 0.5 cm away from the arterial patch and decreased as the measurement approaches the patch. We also observed that the new blood vessels formed are twisted and congested in some areas, in a distinguishable manner from non-pathological blood vessels. To explain these observations, we developed a mathematical model and compared the results from numerical simulations with the experimental data. We introduced a new chemotactic velocity using the temporal change in the chemoattractant gradient to govern the sprout tip migration. We performed a hybrid simulation to illustrate the growth of new vessels. Results indicated the speed of growth of new vessels oscillated before reaching the periphery of the arterial patch. Crowded and congested blood vessel formation was observed during numerical simulations. Thus, our numerical simulation results agreed with the experimental data.

[Postmortem diagnosis of intravascular large B-cell lymphoma after atraumatic splenic rupture due to splenic infiltration].

Atraumatic splenic rupture (ASR) is a rare but fatal complication of malignant lymphoma. However, only one case of intravascular large B-cell lymphoma (IVLBCL)-related ASR (IVLBCL-ASR) has previously been reported, and the mechanism of IVLBCL-ASR is unknown. We present the case of a 78-year-old man who died unexpectedly and was diagnosed with IVLBCL-ASR pathologically by autopsy. A massive intraperitoneal hemorrhage and four lacerations on the splenic surface were discovered during the autopsy. CD20-positive lymphoma cells that infiltrated into small vessels were highly concentrated in the center of the spleen and were only slightly distributed in the lacerations on the splenic surface. Therefore, increased intrasplenic pressure due to lymphoma cell proliferation was identified as the cause of ASR. The patient had undergone 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for tongue cancer evaluation 3 months earlier, and positive uptake was found in the right adrenal gland, where lymphoma cell infiltration was confirmed by the autopsy. Our findings suggest that clinicians should be aware that the advanced stage of IVLBCL can cause fatal ASR via increased intrasplenic pressure. Therefore, early diagnosis and early treatment intervention are desirable to prevent the onset of IVLBCL-ASR, and 18F-FDG PET/CT is useful for the early diagnosis of IVLBCL.

The prognostic role of M2 tumor-associated macrophages in non-small-cell lung cancer.

Lung cancer is a high-risk tumor and is a main cause of death worldwide. The tumor aggressiveness and degree of malignancy depend not only on the tumor itself, but also on the microenvironment. The inflammatory microenvironment is one of the key factors in promoting the progression of lung cancer. It has been found that macrophages are the most abundant immune cells in the tumor microenvironment, with strong plasticity and heterogeneity. Tumor-Associated Macrophages (TAMs) are important components of the tumor immune microenvironment. TAMs are thought to be polarized into two main phenotypes: inflammatory or classically activated (M1) and antiinflammatory or alternatively activated (M2) macrophages. Their phenotype and function change according to environment and the appearance of tumor cells. M2 macrophages have been reported to be protumorigenic, because they can promote the formation of blood vessels in the tumor microenvironment, helping tumor cells escape the body's immune defense and promote their growth, by releasing a variety of cytokines, including chemokines, inflammatory factors and growth factor. However, the prognostic impact of TAMs and their phenotypes in non-small-cell lung cancer (NSCLC) remains to be fully elucidated. Some reports of the association between the characteristics of macrophages in lung tumor and patients' survival outcomes show contradicting results. In order to explore the prognostic role of TAMs in NSCLS, the association between the phenotype, density and distribution of macrophages and the prognosis of human NSCLC, as well as the potential mechanisms of M2 macrophages leading to poor prognosis in NSCLC, are reviewed in this study.

SKAP2 suppresses inflammation-mediated tumorigenesis by regulating SHP-1 and SHP-2.

Inflammatory bowel diseases, like ulcerative colitis and Crohn's disease are frequently accompanied by colorectal cancers. However, the mechanisms underlying colitis-associated cancers are not fully understood. Src Kinase Associated Phosphoprotein 2 (SKAP2), a substrate of Src family kinases, is highly expressed in macrophages. Here, we examined the effects of SKAP2 on inflammatory responses in a mouse model of tumorigenesis with colitis induced by azoxymethane/dextran sulfate sodium. SKAP2 knockout increased the severity of colitis and tumorigenesis, as well as lipopolysaccharide (LPS) induced acute inflammation. SKAP2 attenuated inflammatory signaling in macrophages induced by uptake of cancer cell-derived exosomes. SKAP2-/- mice were characterized by the activation of NF-κB signaling and the upregulation and release of cytokines including TNFα, IL-1ß, IL-6, CXCL-9/-10/-13, and sICAM1; SKAP2 overexpression attenuated NF-κB activation. Mechanistically, SKAP2 formed a complex with the SHP-1 tyrosine phosphatase via association with the Sirpα transmembrane receptor. SKAP2 also physically associated with the TIR domain of MyD88, TIRAP, and TRAM, adaptors of toll-like receptor 4 (TLR4). SKAP2-mediated recruitment of the Sirpα/SHP-1 complex to TLR4 attenuated inflammatory responses, whereas direct interaction of SKAP2 with SHP-2 decreased SHP-2 activation. SHP-2 is required for efficient NF-κB activation and suppresses the TRAM/TRIF-INFß pathway; therefore, SKAP2-mediated SHP-2 inhibition affected two signaling axes from TLR4. The present findings indicate that SKAP2 prevents excess inflammation by inhibiting the TLR4-NF-κB pathway, and it activates the TLR4-IFNß pathway through SHP-1 and SHP-2, thereby suppressing inflammation-mediated tumorigenesis.

Cancer-associated fibroblasts educate normal fibroblasts to facilitate cancer cell spreading and T-cell suppression.

In some tumors, a small number of cancer cells are scattered in a large fibrotic stroma. Here, we demonstrate a novel mechanism for expansion of pro-tumor fibroblasts via cancer-associated fibroblast (CAF)-mediated education of normal fibroblasts (NFs). When NFs were incubated with conditioned medium from CAFs, the resulting CAF-educated fibroblasts (CEFs) generated reactive oxygen species, which induced NF-κB-mediated expression of inflammatory cytokines and the extracellular matrix protein asporin (ASPN), while expression of a common CAF marker gene, α-SMA, was not increased. ASPN further increased CEF expression of downstream molecules, including indoleamine 2,3-dioxygenase 1 (IDO-1), kynureninase (KYNU), and pregnancy-associated plasma protein-A (PAPP-A). These CEFs induce cytocidal effects against CD8+ T cells and IGF-I activation in cancer cells. CEFs were generated without cancer cells by the direct mixture of NFs and CAFs in mouse xenografts, and once CEFs were generated, they sequentially educated NFs, leading to continuous generation of CEFs. In diffuse-type gastric cancers, ASPNhigh /IDO-1high /KYNUhigh /α-SMA- CEFs were located at the distal invading front. These CEFs expanded in the fibrotic stroma and caused dissemination of cancer cells. ASPN may therefore be a key molecule in facilitating tumor spreading and T-cell suppression.

A forensic autopsy case: Sudden unexpected death due to cardiac inflammatory myofibroblastic tumor.

We report an autopsy case of a 25-year-old man with no medical history who died suddenly in an Internet cafe. He was found in cardiorespiratory arrest and did not respond to cardiopulmonary resuscitation. Traumatic lesions were not observed on his body. An autopsy was performed to investigate the cause of death. Upon examination, we discovered a heart tumor that infiltrated from the outside wall to the outflow tract of the left ventricle. Left ventricular outflow tract obstruction due to a cardiac tumor was considered the mechanism of death. Histological examination identified an inflammatory myofibroblastic tumor (IMT). The final diagnosis was death secondary to circulatory failure due to a cardiac IMT. Additionally, a cardiac tumor was diagnosed using post-mortem computed tomography. Only few cases of sudden unexpected death due to cardiac IMT have been reported; we report this case along with a review of the literature.

Disorganization of intercalated discs in dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is a primary myocardial disease, the pathology of which is left ventricular or biventricular dilation and impaired myocardial contractility. The clinical and pathological diagnosis of DCM is difficult, and other cardiac diseases must be ruled out. Several studies have reported pathological findings that are characteristic of DCM, including cardiomyocyte atrophy, nuclear pleomorphism, and interstitial fibrosis, but none of these findings are DCM-specific. In this study, we examined the morphological differences in the intercalated discs (ICDs) between three groups of patients, a DCM group, a chronic heart failure group, and a control group. A total of 22 autopsy cases, including five DCM cases, nine CHF cases and eight control cases, were retrieved from the archives of the Department of Pathology at Akita University, Japan. The morphological differences were examined using multiple methods: macroscopic examination, light microscopy, immunohistochemistry, electron microscopy, and gene expression analyses. We observed disorganized ICDs, clearly illustrated by N-cadherin immunostaining in the DCM group. "Reduction of N-cadherin immunostaining intensity" and "ICD scattering" was DCM-specific. The results suggest that disorganized ICDs contribute to the development of DCM, and that N-cadherin immunostaining is useful for determining the presence of disorganized ICDs and for the pathological diagnosis of DCM.

Collision of Epstein-Barr virus-positive and -negative gastric cancer, diagnosed by molecular analysis: a case report.

BACKGROUND: Epstein-Barr virus (EBV)-positive gastric carcinoma (GC) is defined by the proliferation of GC cells with EBV infection. The co-existence of EBV-positive and -negative components in a single GC is rare. We report a case of GC with the co-existence of EBV-positive and EBV-negative components, in which we performed-for the first time-various molecular analyses to elucidate their histogenesis. CASE PRESENTATION: An 81-year-old man was diagnosed with GC based on the results of endoscopy and a pathological examination of the biopsy specimen. Systemic chemotherapy was performed, since lymph node and lung metastases were diagnosed based on computed tomography. Total gastrectomy and lymph node dissection were performed after chemotherapy, after confirming that the size of the metastatic lymph nodes had decreased and that the lung metastasis had disappeared. Grossly, a type 3 tumor was located in the middle posterior part of the stomach body. At the cut section, the tumor consisted of a white and solid part on the anal side of the tumor and a flat and elevated part on the oral side. Histologically, the former part consisted of GC with lymphoid stroma and the latter part was composed of poorly differentiated adenocarcinoma without prominent lymphocytic infiltration. The two histopathological components were clearly separated from each other. On EBV-encoded small RNA (EBER)-in situ hybridization (ISH), the part with the lymphoid stroma component was positive, while the other part was negative. Immunohistochemistry revealed that both components showed the overexpression of p53. Sequencing of TP53 using DNA extracted from the two components was conducted, and revealed different patterns. Targeted next generation sequencing revealed MYC amplification in the EBV-positive component of the tumor and HER2 amplification in the EBV-negative part. Immunohistochemistry revealed that the EBV-positive part was C-MYC( +)/HER2(-) and the EBV-negative part was C-MYC(-)/HER2( +). Correspondingly, chromogenic ISH and dual-color ISH showed amplification of C-MYC and no amplification of HER2 in the EBV-positive part, and no amplification of C-MYC and amplification of HER2 in the EBV-negative part. CONCLUSION: We presented a case of collision of two different GCs composed of EBER-ISH ( +)/C-MYC ( +) and EBER-ISH (-)/HER2 ( +) cells.

Aberrant Hypermethylation-Mediated Suppression of PYCARD Is Extremely Frequent in Prostate Cancer with Gleason Score ≥ 7.

Epigenetic gene silencing by aberrant DNA methylation leads to loss of key cellular pathways in tumorigenesis. In order to analyze the effects of DNA methylation on prostate cancer, we established LNCaP-derived human prostate cancer cells that can pharmacologically induce global reactivation of hypermethylated genes by the methyl-CpG targeted transcriptional activation (MeTA) method. The MeTA suppressed the growth of LNCaP-derived cells and induced apoptosis. Microarray analysis indicated that PYCARD (PYD and CARD domain containing) encoding an apoptosis-inducing factor was upregulated by 65-fold or more after treatment with MeTA. We analyzed DNA methylation statuses using 50 microdissected primary prostate cancer tissues and found an extremely high frequency of tumor-specific promoter hypermethylation of PYCARD (90%, 45/50). Moreover, DNA methylation status was significantly associated with Gleason score (P = 0.0063); the frequency of tumor-specific hypermethylation was 96% (44/46) in tumors with Gleason score ≥ 7, whereas that in tumors with Gleason score 6 was 25% (1/4). Immunohistochemical analyses using these 50 cases indicated that only 8% (4/50) of cancerous tissues expressed PYCARD, whereas 80% (40/50) of corresponding normal prostate epithelial and/or basal cells expressed PYCARD. In addition, there was no relationship between PYCARD immunostaining and the Gleason score in cancerous tissue and surrounding normal tissue. Inducible expression of PYCARD inhibited cell proliferation by induction of apoptosis. These results suggest that aberrant methylation of PYCARD is a distinctive feature of prostate cancers with Gleason score ≥ 7 and may play an important role in escaping from apoptosis in prostatic tumorigenesis.

PD-L1 overexpression in EBV-positive gastric cancer is caused by unique genomic or epigenomic mechanisms.

Epstein-Barr virus-positive gastric cancer [EBV (+) GC] is a distinct GC subtype with unique genetic and epigenetic aberrations. Here, we examined resected GC samples and publicly available microarray data and The Cancer Genome Atlas (TCGA) database to identify the mechanism underlying overexpression of PD-L1 in EBV (+) GC. We found that high levels of PD-L1 overexpression in EBV (+) GC were caused by focal amplification of CD274. By contrast, relatively high expression of PD-L1 in tumor tissue and infiltrating immune cells correlated with CD8 lymphocyte infiltration and IFN-γ expression via IRF3 activation. Since we reported previously that PD-L1 expression is associated both with the presence of CD8 T cells in the tumor microenvironment and with IFN-γ expression in GC, we examined a database to see whether IFN-γ-associated overexpression of PD-L1 plays a significant role in EBV (+) GC. Immunohistochemical staining showed that expression of the IRF3 signature in clinical GC samples was higher in EBV (+) than in EBV (-) cases. The data presented herein reveal a unique dual mechanism underlying PD-L1 overexpression in EBV (+) GC: high focal amplification of CD274 or IFN-γ-mediated signaling via activation of IRF3.

Detection of MED12 mutations in mesenchymal components of uterine adenomyomas.

Adenomyoma of the uterus is a biphasic nodular lesion composed of a mesenchymal component with smooth muscle differentiation and a glandular epithelium. The neoplastic nature of uterine adenomyomas has been controversial because some are considered to be nodular adenomyosis. MED12 mutations are involved in the pathogenesis of uterine smooth muscle tumors (leiomyomas and leiomyosarcomas) and biphasic tumors of the breast (fibroadenomas and phyllodes tumor). To investigate the histogenesis of uterine adenomyomas, we performed pathological and genetic analyses, including Sanger sequencing of MED12. In total, 15 cases of uterine adenomyomas were retrieved and assessed for clinicopathological factors. Immunohistochemistry for smooth muscle actin, desmin, and CD10 was performed. Exon 2 of MED12 was Sanger sequenced using DNA obtained by macrodissection of the adenomyomas. For cases that were positive for somatic MED12 mutations, we next performed microdissection of the mesenchymal and epithelial components. The DNA extracted from each component was further analyzed for MED12 mutations. MED12 mutations were detected in two adenomyomas (2/15, 13%), all in a known hot spot (codon 44). In both lesions, MED12 mutations were detected in multiple spots of the mesenchymal component. The epithelial component did not harbor MED12 mutations. The relatively low frequency of MED12 mutations suggests that not all adenomyomas are leiomyomas with entrapped glands. However, the results of our study suggest that a subset of uterine adenomyomas are true mesenchymal neoplasms.