The specific shapes of capillaries are associated with worse prognosis in patients with invasive breast cancer.

Angiogenesis is considered essential for tumor progression; however, whether histological counting of blood vessel numbers, expressed as microvessel density (MVD), can be a prognostic factor in breast cancer remains controversial. It has been suggested that the specific morphology of blood vessels such as glomeruloid microvascular proliferation (GMP) is associated with clinical parameters. Here, we aimed to clarify the significance of MVD with revised immunohistochemistry and to identify new blood vessel shapes that predict prognosis in breast cancer. Four hundred and eleven primary breast cancer specimens were collected, and the sections were immunohistochemically stained with CD31 (single staining) and CD31 and Collagen IV (double staining). The prognosis of patients was examined based on the MVD value, and the presence of GMP and other blood vessels with other specific shapes. As a result, high MVD value and the presence of GMP were not associated with worse prognosis. By contrast, patients with deep-curved capillaries surrounding tumor cell nests (C-shaped) or excessively branched capillaries near tumor cell nests showed a significantly poor prognosis. The presence of these capillaries was also correlated with clinicopathological parameters such as Ki-67 index. Thus, the morphology of capillaries rather than MVD can be a better indicator of tumor aggressiveness.

SPRED2 Is a Novel Regulator of Autophagy in Hepatocellular Carcinoma Cells and Normal Hepatocytes.

Sprouty-related enabled/vasodilator-stimulated phosphoprotein homology 1 domain containing 2 (SPRED2) is an inhibitor of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway and has been shown to promote autophagy in several cancers. Here, we aimed to determine whether SPRED2 plays a role in autophagy in hepatocellular carcinoma (HCC) cells. The Cancer Genome Atlas (TCGA) Liver Cancer Database showed a negative association between the level of SPRED2 and p62, a ubiquitin-binding scaffold protein that accumulates when autophagy is inhibited. Immunohistochemically, accumulation of p62 was detected in human HCC tissues with low SPRED2 expression. Overexpression of SPRED2 in HCC cells increased the number of autophagosomes and autophagic vacuoles containing damaged mitochondria, decreased p62 levels, and increased levels of light-chain-3 (LC3)-II, an autophagy marker. In contrast, SPRED2 deficiency increased p62 levels and decreased LC3-II levels. SPRED2 expression levels were negatively correlated with translocase of outer mitochondrial membrane 20 (TOM20) expression levels, suggesting its role in mitophagy. Mechanistically, SPRED2 overexpression reduced ERK activation followed by the mechanistic or mammalian target of rapamycin complex 1 (mTORC1)-mediated signaling pathway, and SPRED2 deficiency showed the opposite pattern. Finally, hepatic autophagy was impaired in the liver of SPRED2-deficient mice with hepatic lipid droplet accumulation in response to starvation. These results indicate that SPRED2 is a critical regulator of autophagy not only in HCC cells, but also in hepatocytes, and thus the manipulation of this process may provide new insights into liver pathology.

SPRED2: A Novel Regulator of Epithelial-Mesenchymal Transition and Stemness in Hepatocellular Carcinoma Cells.

The downregulation of SPRED2, a negative regulator of the ERK1/2 pathway, was previously detected in human cancers; however, the biological consequence remains unknown. Here, we investigated the effects of SPRED2 loss on hepatocellular carcinoma (HCC) cell function. Human HCC cell lines, expressing various levels of SPRED2 and SPRED2 knockdown, increased ERK1/2 activation. SPRED2-knockout (KO)-HepG2 cells displayed an elongated spindle shape with increased cell migration/invasion and cadherin switching, with features of epithelial-mesenchymal transition (EMT). SPRED2-KO cells demonstrated a higher ability to form spheres and colonies, expressed higher levels of stemness markers and were more resistant to cisplatin. Interestingly, SPRED2-KO cells also expressed higher levels of the stem cell surface markers CD44 and CD90. When CD44+CD90+ and CD44-CD90- populations from WT cells were analyzed, a lower level of SPRED2 and higher levels of stem cell markers were detected in CD44+CD90+ cells. Further, endogenous SPRED2 expression decreased when WT cells were cultured in 3D, but was restored in 2D culture. Finally, the levels of SPRED2 in clinical HCC tissues were significantly lower than those in adjacent non-HCC tissues and were negatively associated with progression-free survival. Thus, the downregulation of SPRED2 in HCC promotes EMT and stemness through the activation of the ERK1/2 pathway, and leads to more malignant phenotypes.

Exosomal Wnt7a from a low metastatic subclone promotes lung metastasis of a highly metastatic subclone in the murine 4t1 breast cancer.

BACKGROUND: Patients with triple-negative breast cancer (TNBC) often have poorer prognosis than those with other subtypes because of its aggressive behaviors. Cancer cells are heterogeneous, and only a few highly metastatic subclones metastasize. Although the majority of subclones may not metastasize, they could contribute by releasing factors that increase the capacity of highly metastatic cells and/or provide a favorable tumor microenvironment (TME). Here, we analyzed the interclonal communication in TNBC which leads to efficient cancer progression, particularly lung metastasis, using the polyclonal murine 4T1 BC model. METHODS: We isolated two 4T1 subclones, LM.4T1 and HM.4T1 cells with a low and a high metastatic potential, respectively, and examined the effects of LM.4T1 cells on the behaviors of HM.4T1 cells using the cell scratch assay, sphere-forming assay, sphere invasion assay, RT-qPCR, and western blotting in vitro. We also examined the contribution of LM.4T1 cells to the lung metastasis of HM.4T1 cells and TME in vivo. To identify a critical factor which may be responsible for the effects by LM.4T1 cells, we analyzed the data obtained from the GEO database. RESULTS: Co-injection of LM.4T1 cells significantly augmented lung metastases by HM.4T1 cells. LM.4T1-derived exosomes promoted the migration and invasion of HM.4T1 cells in vitro, and blocking the secretion of exosome abrogated their effects on HM.4T1 cells. Analyses of data obtained from the GEO database suggested that Wnt7a might be a critical factor responsible for the enhancing effects. In fact, a higher level of Wnt7a was detected in LM.4T1 cells, especially in exosomes, than in HM.4T1 cells, and deletion of Wnt7a in LM.4T1 cells significantly decreased the lung metastasis of HM.4T1 cells. Further, treatment with Wnt7a increased the spheroid formation by HM.4T1 cells via activation of the PI3K/Akt/mTOR signaling pathway. Finally, infiltration of αSMA-positive fibroblasts and angiogenesis was more prominent in tumors of LM.4T1 cells and deletion of Wnt7a in LM.4T1 cells markedly reduced angiogenesis. CONCLUSIONS: We demonstrated, for the first time, that a low metastatic subclone can enhance lung metastasis of highly metastatic subclone via exosomal Wnt7a and propose Wnt7a as a molecular target to treat TNBC patients.

Crosstalk between Cancer Cells and Fibroblasts for the Production of Monocyte Chemoattractant Protein-1 in the Murine 4T1 Breast Cancer.

The chemokine monocyte chemoattractant protein-1 (MCP-1/CCL2) is shown to promote the progression of breast cancer. We previously identified cancer cell-derived granulocyte-macrophage colony-stimulating factor (GM-CSF) as a potential regulator of MCP-1 production in the murine 4T1 breast cancer, but it played a minimum role in overall MCP-1 production. Here, we evaluated the crosstalk between 4T1 cells and fibroblasts. When fibroblasts were co-cultured with 4T1 cells or stimulated with the culture supernatants of 4T1 cells (4T1-sup), MCP-1 production by fibroblasts markedly increased. 4T1 cells expressed mRNA for platelet-derived growth factor (PDGF)-a, b and c, and the PDGF receptor inhibitor crenolanib almost completely inhibited 4T1-sup-induced MCP-1 production by fibroblasts. However, PDGF receptor antagonists failed to reduce MCP-1 production in tumor-bearing mice. Histologically, 4T1 tumors contained a small number of αSMA-positive fibroblasts, and Mcp-1 mRNA was mainly associated with macrophages, especially those surrounding necrotic lesions on day 14, by in situ hybridization. Thus, although cancer cells have the capacity to crosstalk with fibroblasts via PDGFs, this crosstalk does not play a major role in MCP-1 production or cancer progression in this model. Unraveling complex crosstalk between cancer cells and stromal cells will help us identify new targets to help treat breast cancer patients.

Detection of cutaneous prion protein deposits could help diagnose GPI-anchorless prion disease with neuropathy.

BACKGROUND AND PURPOSE: To investigate prion protein (PrP) deposits in cutaneous tissues of patients of glycosylphosphatidylinositol (GPI)-anchorless prion diseases with neuropathy. METHODS: Cutaneous tissue samples from three patients with GPI-anchorless prion diseases were obtained, two cutaneous biopsy samples from the lower leg of Case 1 (Y162X) and Case 3 (D178fs25), and a cutaneous sample taken from the abdomen during an autopsy of Case 2 (D178fs25). We performed immunohistochemistry for PrP to look for abnormal PrP deposits. RESULTS: PrP deposits were observed in the dermal papilla, the sweat glands, the hair follicles, the arrector pili muscles, and peripheral nerves of all examined cases of GPI-anchorless prion disease with neuropathy. The abnormal PrP accumulation was frequently localized at the basement membrane, and colocalized with laminin. CONCLUSION: Immunohistochemical detection of PrP in cutaneous samples could be used to definitively diagnose GPI-anchorless PrP disease with neuropathy.

PolyI:C suppresses TGF-ß1-induced Akt phosphorylation and reduces the motility of A549 lung carcinoma cells.

BACKGROUNDS: Epithelial mesenchymal transition (EMT) is a critical process involved in the invasion and metastasis of cancer, including lung cancer (LC). Transforming growth factor (TGF)-ß is one of factors capable of inducing EMT. Polyinosinic-polycytidylic acid (polyI:C), a synthetic agonist for toll-like receptor (TLR) 3, can enhance immune responses and has been used as an adjuvant for cancer vaccines; however, it remains unclear whether it influences other process, such as EMT. In the present study, we examined the effects of polyI:C on TGF-ß-treated A549 human LC cells. METHODS AND RESULTS: By in vitro cell proliferation assay, polyI:C showed no effect on the growth of A549 cells treated with TGF-ß1 at the concentration range up to 10 µg/ml; however, it markedly suppressed the motility in a cell scratch and a cell invasion assay. By Western blotting, polyI:C dramatically decreased TGF-ß1-induced Ak strain transforming (Akt) phosphorylation and increased phosphatase and tensin homologue (PTEN) expression without affecting the Son of mothers against decapentaplegic (Smad) 3 phosphorylation or the expression level of E-cadherin, N-cadherin or Snail, indicating that polyI:C suppressed cell motility independently of the 'cadherin switching'. The Akt inhibitor perifosine inhibited TGF-ß1-induced cell invasion, and the PTEN-specific inhibitor VO-OHpic appeared to reverse the inhibitory effect of polyI:C. CONCLUSION: PolyI:C has a novel function to suppress the motility of LC cells undergoing EMT by targeting the phosphatidylinositol 3-kinase/Akt pathway partly via PTEN and may prevent or reduce the metastasis of LC cells.

Elastin and collagen IV double staining: A refined method to detect blood vessel invasion in breast cancer.

Blood vessel invasion (BVI) is a prognostic indicator in various cancers. Elastic stain, which highlights blood vessel walls, is commonly used to detect BVI. In the breast, however, its diagnostic usefulness is limited because it also highlights some intraductal carcinoma components, which often mimic BVI. In this study, we aimed to improve BVI detection in breast cancer and developed a double staining: Victoria blue for elastin and immunohistochemistry for collagen IV. Collagen IV fibers were retained along the basement membranes of intraductal carcinoma components, whereas they were rearranged or lost in BVI. From these observations, we defined BVI as the presence of tumor cells inside an elastic ring with a rearrangement or loss of collagen IV fibers. Using these criteria, we found BVI in 148 cases (49%) among 304 cases of primary operable invasive breast carcinoma, and the presence of BVI correlated significantly with poor prognosis. By contrast, we detected BVI in 94 cases (31%) or 14 cases (5%) by elastic van Gieson or CD31 immunostaining among the same cases, respectively, with no statistically significant association with prognosis. Thus, elastin and collagen IV double staining facilitates the detection of BVI in breast cancer and is useful to predict prognosis.

Juvenile Granulosa Cell Tumor with an Unusual Clinical Course: A Late-onset and Late Recurrent Case.

Juvenile granulosa cell tumors (JGCTs) are rare ovarian tumors with overall good prognoses. They differ from adult granulosa cell tumors (AGCTs), which are well known for late recurrence. Most JGCTs (～97%) occur in individuals <30 years old. We report a recurrent JGCT in a 40-year-old woman 5 years after initial presentation. The histological appearance and lack of 402C>G missense point mutation of FOXL2 gene (characteristic of AGCT but absent in JGCT) allowed differentiation from AGCT. This is the first comprehensive report of JGCT with late recurrence. Although rare, late recurrence of JGCT can occur; long-term surveillance is suggested.

SOCS3 overexpression in T cells ameliorates chronic airway obstruction in a murine heterotopic tracheal transplantation model.

PURPOSE: Suppressor of cytokine signaling-3 (SOCS3) is a negative feedback inhibitor of cytokine signaling with T-cell-mediated immunosuppressive effects on obliterative bronchiolitis (OB). In this study, we aimed to investigate the impact of T-cell-specific overexpression of SOCS3 using a murine heterotopic tracheal transplantation (HTT) model. METHODS: Tracheal allografts from BALB/c mice were subcutaneously transplanted into wild-type C57BL/6J (B6; WT) mice and SOCS3 transgenic B6 (SOCS3TG) mice. Tracheal allografts were analyzed by immunohistochemistry and quantitative polymerase chain reaction assays at days 7 and 21. RESULTS: At day 21, allografts in SOCS3TG mice showed significant amelioration of airway obstruction and epithelial loss compared with allografts in WT mice. The intragraft expression of IFN-γ and CXCL10 was suppressed, while that of IL-4 was enhanced in SOCS3TG mice at day 7. The T-bet levels were lower in SOCS3TG allografts than in WT allografts at day 7. CONCLUSION: We revealed that the overexpression of SOCS3 in T cells effectively ameliorates OB development in a murine HTT model by inhibiting the Th1 phenotype in the early phase. Our results suggest that the regulation of the T-cell response, through the modulation of SOCS expression, has potential as a new therapeutic strategy for chronic lung allograft dysfunction.

Cancer Cell-Derived Granulocyte-Macrophage Colony-Stimulating Factor Is Dispensable for the Progression of 4T1 Murine Breast Cancer.

We previously reported that 4T1 murine breast cancer cells produce GM-CSF that up-regulates macrophage expression of several cancer promoting genes, including Mcp-1/Ccl2, Ccl17 and Rankl, suggesting a critical role of cancer cell-derived GM-CSF in cancer progression. Here, we attempted to define whether 4T1 cell-derived GM-CSF contributes to the expression of these genes by 4T1tumors, and their subsequent progression. Intraperitoneal injection of anti-GM-CSF neutralizing antibody did not decrease the expression of Mcp-1, Ccl17 or Rankl mRNA by 4T1 tumors. To further examine the role of cancer cell-derived GM-CSF, we generated GM-CSF-deficient 4T1 cells by using the Crisper-Cas9 system. As previously demonstrated, 4T1 cells are a mixture of cells and cloning of cells by itself significantly reduced tumor growth and lung metastasis. By contrast, GM-CSF-deficiency did not affect tumor growth, lung metastasis or the expression of these chemokine and cytokine genes in tumor tissues. By in-situ hybridization, the expression of Mcp-1 mRNA was detected in both F4/80-expressing and non-expressing cells in tumors of GM-CSF-deficient cells. These results indicate that cancer cell-derived GM-CSF is dispensable for the tuning of the 4T1 tumor microenvironment and the production of MCP-1, CCL17 or RANKL in the 4T1 tumor microenvironment is likely regulated by redundant mechanisms.

Tracheal stenosis caused by unnoticed foreign bodies.

We describe an extremely rare case of tracheal stenosis caused by unnoticed microscopic fiber-like foreign bodies. A 66-year-old woman complained of dyspnea with inspiratory stridor. Magnifying electroendoscopy and computed tomography revealed stenosis involving the entire circumference of the tracheal lumen. Tracheotomy and biopsy were performed. Histologically, the lesion showed chronic inflammation with a deposition of fiber-like foreign bodies. The patient had no history of trauma or inhalation injury, but had undergone intratracheal intubation on 4 occasions. The lesion was incised using semiconductor laser photoresection, and the postoperative course was good. To the best of our knowledge, this represents the first report in the English literature of tracheal stenosis caused by unnoticed foreign bodies. The origin of these fiber-like foreign bodies remains unclear but might be related to chronic inflammation resulting from intratracheal intubations.

Oxaliplatin-induced liver injury mimicking metastatic tumor on images: a case report.

Oxaliplatin-based chemotherapy is widely used for advanced colorectal cancer treatment, but it occasionally induces liver injury that is characterized histologically by sinusoidal dilatation, hepatic plate atrophy and/or venular obstruction. Most of the patients do not reveal apparent radiological abnormalities, however. Here, we report the case of a 47-year-old man with a radiologically detectable mass-forming oxaliplatin-induced sinusoidal injury that mimicked multiple liver tumors. These mass lesions were found on computed tomography images after the administration of six cycles of folinic acid, fluorouracil and oxaliplatin therapy as adjuvant chemotherapy for Stage III rectal cancer. The patient had to undergo liver resection because imaging studies could not exclude metastases. The histological examination revealed that a resected mass lesion was composed of severe sinusoidal dilatation. Milder dilatation was also seen in the surrounding parenchyma. We diagnosed the patient as having an oxaliplatin-induced sinusoidal injury with severe deviation. As oxaliplatin is a standard agent in colorectal cancer therapy today, all clinicians and pathologists should be aware of such non-neoplastic lesions as one of the rare differential diagnoses of metastatic liver tumor, to prevent overtreatment.

Factors that make it difficult to diagnose cervical tuberculous lymphadenitis.

Cervical tuberculous lymphadenitis is mainly diagnosed by analyzing tissue samples obtained by fine-needle aspiration (FNA). However, some cases remain diagnostic challenges even after polymerase chain reaction analysis of FNA specimens. To delineate differences between cases that are relatively easy to diagnose and those for which diagnosis is difficult, 22 patients with cervical tuberculous lymphadenitis were studied retrospectively. FNA tissues were used to diagnose 14 cases (group A), whereas excisional biopsy was required for accurate diagnosis of 8 cases (group B). These two groups were compared with regard to results of blood examinations, ultrasound appearance, and various other procedures required to reach the final diagnosis. The results indicated that diagnosis of cervical tuberculous lymphadenitis was more difficult for patients with lower white blood cell counts, lower serum C-reactive protein levels, and absence of lymph node fusion or abscess formation on ultrasonography. The possibility of tuberculosis as a cause of cervical lymphadenopathy should always be considered, even when the presenting symptoms are not typical of this disease.

Papillary thyroid carcinoma arising from a median ectopic thyroid with no thyroglossal duct remnant.

Thyroid carcinomas arising from ectopic thyroid tissue are uncommon;most of them arise from thyroid tissue in thyroglossal cysts. A rare case of a 66-year-old woman with papillary thyroid carcinoma arising from median ectopic thyroid tissue lacking a thyroglossal duct remnant is reported. The tumor was resected by Sistrunk's procedure, and the patient's postoperative course was good.

Highly Metastatic Subpopulation of TNBC Cells Has Limited Iron Metabolism and Is a Target of Iron Chelators.

Excess iron is known to be a risk factor of carcinogenesis. Although iron chelators show anti-cancer effects, they have not been used successfully to treat cancer patients. Triple-negative breast cancer (TNBC) is a disease with poor prognosis without effective treatments. Thus, we aimed to evaluate a possibility of iron chelators as a therapy for TNBC. Deferasirox (DFX), an iron chelator, suppressed the growth of 4T1 murine TNBC cell line cells in vitro and in vivo. Lung metastasis was further significantly reduced, leading to the hypothesis that iron metabolism between metastatic and non-metastatic cells may be different. An analysis of existing database demonstrated that the expression of iron-uptake genes was significantly suppressed in TNBC cells that metastasized to lymph nodes or lungs compared to those in primary tumors. A highly metastatic clone of the murine 4T1 TNBC cells (4T1-HM) did not proliferate well under iron-rich or iron-depleted conditions by iron chelators compared to a low-metastatic clone (4T1-LM). Bulk RNA-seq analysis of RNA from 4T1-HM and 4T1-LM cells suggested that the PI3K-AKT pathway might be responsible for this difference. Indeed, DFX suppressed the proliferation via the AKT-mTOR pathway in 4T1-HM and the human MDA-MB-231 cells, a human mesenchymal-like TNBC cell line. DFX also suppressed the growth of 4T1-HM tumors in comparison to 4T1-LM tumors, and reduced lung metastases after surgical resection of primary 4T1 tumors. These results indicated, for the first time, that highly metastatic TNBC cells have limited iron metabolism, and they can be more effectively targeted by iron chelators.

Endometrial polyps: MR imaging features.

The purpose of this study is to evaluate the diagnostic usefulness of magnetic resonance imaging (MRI) characteristics of endometrial polyps in order to differentiate them from other endometrial lesions. MRI was retrospectively reviewed in 40 patients with pathologically proven endometrial polyps. Special attention was paid to the sizes, shapes, margins, internal structures, signal intensities, and post-contrast enhancement patterns. A central fibrous core, intratumoral cysts, and hemorrhage were seen in 30 (75%), 22 (55%), and 14 (35%) patients, respectively. The predominant signal intensity of the lesions showed iso-to slightly low signal intensity relative to the endometrium on T2-weighted images in 36 (90%), low signal intensity on diffusion-weighted images in 32 (80%), and strong or moderate enhancement on enhanced T1-weighted images in 28 patients (70%), respectively. In 32 (80%) patients, the endometrial polyps showed global or partial early enhancement. On dynamic study, rapid enhancement with a persistent strong enhancement pattern was seen in 17 (42.5%) and a gradually increasing enhancement pattern was seen in 17 patients (42.5%). These MRI features can be helpful to distinguish the endometrial polyps from various other endometrial lesions.

Thioredoxin interacting protein protects mice from fasting induced liver steatosis by activating ER stress and its downstream signaling pathways.

Under normal conditions, fasting results in decreased protein disulfide isomerase (PDI) activity and accumulation of unfolded proteins, leading to the subsequent activation of the unfolded protein response (UPR)/autophagy signaling pathway to eliminate damaged mitochondria. Fasting also induces upregulation of thioredoxin-interacting protein (TXNIP) expression and mice deficient of this protein (TXNIP-KO mice) was shown to develop severe hypoglycemia, hyperlipidemia and liver steatosis (LS). In the present study, we aimed to determine the role of TXNIP in fasting-induced LS by using male TXNIP-KO mice that developed LS without severe hypoglycemia. In TXNIP-KO mice, fasting induced severe microvesicular LS. Examinations by transmission electron microscopy revealed mitochondria with smaller size and deformities and the presence of few autophagosomes. The expression of ß-oxidation-associated genes remained at the same level and the level of LC3-II was low. PDI activity level stayed at the original level and the levels of p-IRE1 and X-box binding protein 1 spliced form (sXBP1) were lower. Interestingly, treatment of TXNIP-KO mice with bacitracin, a PDI inhibitor, restored the level of LC3-II after fasting. These results suggest that TXNIP regulates PDI activity and subsequent activation of the UPR/autophagy pathway and plays a protective role in fasting-induced LS.

Diagnostic Utility of the PD-L1 Immunostaining in Biopsy Specimens of Patients with Biliary Tract Neoplasms.

BACKGROUND: Anti-programmed death 1/programmed death ligand 1 (PD1/PD-L1) antibodies have been successfully used as treatment agents for several solid tumors; however, it is difficult to predict their effectiveness. We evaluated whether biopsy specimens could predict the positive status of PD-L1 in surgically resected tissue. METHODS: Among 91 patients who underwent tissue sampling with endoscopic or liver biopsy before surgery for biliary tract neoplasms in an academic center, 45 (49%) patients were selected for retrospective analysis because the quality and quantity of their biopsy specimens were adequate for histologic evaluation. We performed immunohistochemical staining to investigate the PD-L1 expression in both resected and biopsy specimens. The percentage of the positively stained cells was calculated for subsequent use in the correlation investigation. RESULTS: The biopsy methods were endoscopic retrograde cholangiopancreatography (ERCP) in 28 cases, percutaneous liver biopsy in 10 cases, and endoscopic ultrasound fine-needle aspiration in 7 cases. Among the 45 patients, when patients with > 10% positive tumor cells in surgically resected tissues were regarded as truly positive PD-L1, the positive and negative concordance rates between surgically resected tissues and biopsy samples were 56% (5/9) and 100% (36/36), respectively. With regard to the use of preoperative biopsy as a diagnostic tool, all (5/5) PD-L1-positive patients had a positive resected specimen. The accuracy of each biopsy method was as follows: ERCP, 89% (25/28); fine-needle aspiration, 86% (6/7); and liver biopsy, 100% (10/10). CONCLUSIONS: Biopsy samples could be a surrogate material for the assessment of the PD-L1 expression with substantial positive and high negative concordance rates.

Spred2 controls the severity of Concanavalin A-induced liver damage by limiting interferon-gamma production by CD4+ and CD8+ T cells.

Introduction: Mitogen-activated protein kinases (MAPKs) are involved in T cell-mediated liver damage. However, the inhibitory mechanism(s) that controls T cell-mediated liver damage remains unknown. Objectives: We investigated whether Spred2 (Sprouty-related, EVH1 domain-containing protein 2) that negatively regulates ERK-MAPK pathway has a biological impact on T cell-mediated liver damage by using a murine model. Methods: We induced hepatotoxicity in genetically engineered mice by intravenously injecting Concanavalin A (Con A) and analyzed the mechanisms using serum chemistry, histology, ELISA, qRT-PCR, Western blotting and flow cytometry. Results: Spred2-deficient mice (Spred2-/-) developed more sever liver damage than wild-type (WT) mice with increased interferon-γ (IFNγ) production. Hepatic ERK phosphorylation was enhanced in Spred2-/- mice, and pretreatment of Spred2-/- mice with the MAPK/ERK inhibitor U0126 markedly inhibited the liver damage and reduced IFNγ production. Neutralization of IFNγ abolished the damage with decreased hepatic Stat1 activation in Spred2-/- mice. IFNγ was mainly produced from CD4+ and CD8+ T cells, and their depletion decreased liver damage and IFNγ production. Transplantation of CD4+ and/or CD8+ T cells from Spred2-/- mice into RAG1-/- mice deficient in both T and B cells caused more severe liver damage than those from WT mice. Hepatic expression of T cell attractants, CXCL9 and CXCL10, was augmented in Spred2-/- mice as compared to WT mice. Conversely, liver damage, IFNγ production and the recruitment of CD4+ and CD8+ T cells in livers after Con A challenge were lower in Spred2 transgenic mice, and Spred2-overexpressing CD4+ and CD8+ T cells produced lower levels of IFNγ than WT cells upon stimulation with Con A in vitro. Conclusion: We demonstrated, for the first time, that Spred2 functions as an endogenous regulator of T cell IFNγ production and Spred2-mediated inhibition of ERK-MAPK pathway may be an effective remedy for T cell-dependent liver damage.