An Analysis of Delayed Bleeding in Cases of Colorectal Endoscopic Submucosal Dissection Due to Types of Direct Oral Anticoagulants in Japan.

BACKGROUND & AIMS: Reported rates of delayed bleeding (DB) after endoscopic resection using direct oral anticoagulants (DOACs) are high and heterogeneous. This large-scale multicenter study analyzed cases of DB after colorectal endoscopic submucosal dissection related to various types of DOACs in Japan (the ABCD-J study) with those associated with warfarin. METHODS: We retrospectively reviewed 1019 lesions in patients treated with DOACs and 459 lesions in patients treated with warfarin among 34,455 endoscopic submucosal dissection cases from 47 Japanese institutions between 2012 and 2021. The DB rate (DBR) with each DOAC was compared with that with warfarin. Risk factors for DB in patients treated with DOACs or warfarin were also investigated. RESULTS: The mean tumor sizes in the DOAC and warfarin groups were 29.6 ± 14.0 and 30.3 ± 16.4 mm, respectively. In the DOAC group, the DBR with dabigatran (18.26%) was significantly higher than that with apixaban (10.08%, P = .029), edoxaban (7.73%, P = .001), and rivaroxaban (7.21%, P < .001). Only rivaroxaban showed a significantly lower DBR than warfarin (11.76%, P = .033). In the multivariate analysis, heparin bridging therapy (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.27-3.73, P = .005), rectal location (2.01, 1.28-3.16, P = .002), and procedure time ≥55 minutes (2.43, 1.49-3.95, P < .001) were significant risk factors for DB in the DOAC group. The DB risk in the DOAC group (OR, (95% CI)) was 2.13 (1.30-3.50) and 4.53 (2.52-8.15) for 1 and 2 significant risk factors, respectively. CONCLUSIONS: Dabigatran was associated with a higher DBR than other DOACs, and only rivaroxaban was associated with a significantly lower DBR than warfarin.

Inflammatory Hepatocellular Adenoma Mimicking Focal Nodular Hyperplasia That Grew during Pregnancy and Changed Its Appearance on Magnetic Resonance Imaging after Delivery.

We reported a notable case of inflammatory hepatocellular adenoma that grew during pregnancy, consequently changing its appearance on magnetic resonance imaging remarkably. A 5-months-pregnant 35-year-old woman presented with a 37-mm liver nodule that had been diagnosed as focal nodular hyperplasia 3 years earlier. She had never used oral contraceptives. After 2 months, the nodule grew to 57 mm. The patient delivered a full-term infant without complications. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging performed after delivery revealed markedly different findings compared with the first images. A liver biopsy was performed, and the tumor was diagnosed as inflammatory hepatocellular adenoma.

Clinical characteristics of adult T-cell leukemia/lymphoma infiltration in the gastrointestinal tract.

BACKGROUND: Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell malignancy caused by human T-cell leukemia virus type 1. The clinical course of ATLL is very heterogeneous, and many organs, including the gastrointestinal (GI) tract, can be involved. However, there are few detailed reports on ATLL infiltration in the GI tract. We investigated the clinical characteristics of ATLL infiltration in the GI tract. METHODS: This retrospective observational single-center study included 40 consecutive ATLL patients who underwent GI endoscopy. The patients' demographic and clinical characteristics and endoscopic findings were analyzed retrospectively. Patients with ATLL who were diagnosed by histological examination were divided into two groups based on GI tract infiltration. RESULTS: Multivariate analysis revealed that the absence of skin lesions was significantly associated with GI infiltration (P < 0.05). Furthermore, the infiltration group tended to have similar macroscopic lesions in the upper and lower GI tracts, such as diffuse type, tumor-forming type, and giant-fold type. CONCLUSIONS: GI endoscopy may be considered for ATLL patients without skin lesions.

Single Rectal Neuroendocrine Tumor Associated with Multiple Endocrine Cell Micronests.

Although a few reports of neuroendocrine tumor (NET) in the stomach or appendix with surrounding micronests have been published, cases of rectal NET are rare. We herein report a unique case of a patient with single rectal NET treated endoscopically. A pathological examination revealed multiple endocrine cell micronests (ECMs) in the submucosal layer around the main NET lesion. Neither lymph node metastasis nor distant metastasis in computed tomography was observed six years after the treatment. Because case reports of multiple ECM are very rare, the significance of malignancy is unclear. It therefore appears to be necessary to accumulate similar cases.

Mice with Calr mutations homologous to human CALR mutations only exhibit mild thrombocytosis.

Calreticulin (CALR) exon 9 frameshift mutations, commonly detected in essential thrombocythemia (ET) and primary myelofibrosis patients, activate signal transducer and activator of transcription (STAT) proteins in the presence of Myeloproliferative Leukemia Virus (MPL) and induce ET in vivo. Loss of the KDEL motif, an endoplasmic reticulum retention signal, and generation of many positively charged amino acids (AAs) in the mutated C-terminus are thought to be important for disease induction. To test this hypothesis, we generated mice harboring a Calr frameshift mutation using the CRISPR/Cas9 system. Deletion of 19-base pairs in exon 9 (c.1099-1117del), designated the del19 mutation, induced loss of the KDEL motif and generated many positively charged AAs, similar to human mutants. Calr del19 mice exhibited mild thrombocytosis, slightly increased megakaryocytes, and mild splenomegaly. In vitro experiments revealed that the murine CALR del19 mutant had a weaker ability to combine with murine MPL than the human CALR del52 mutant. Consequently, STAT5 activation was also very weak downstream of the murine mutant and murine MPL, and may be the reason for the mild disease severity. In summary, loss of the KDEL motif and positively charged AAs in the C-terminus of CALR is insufficient for MPL binding and ET development.

Multicenter prospective study on the histological diagnosis of gastric cancer by narrow band imaging-magnified endoscopy with and without acetic acid.

Background and study aims The usefulness of endoscopy for diagnosing histological type remains unclear. This study aimed to examine the diagnostic accuracy of white light endoscopy (WLE), magnified endoscopy with narrow band imaging (NBI-ME), and NBI-ME with acetic acid enhancement (NBI-AA) for histological type of gastric cancer. Patients and methods Patients with depressed-type gastric cancers resected by endoscopic submucosal dissection were prospectively enrolled, and 221 cases were analyzed. Histological type was diagnosed by WLE, followed by NBI-ME and NBI-AA. Histological type was classified into differentiated adenocarcinoma and undifferentiated adenocarcinoma. Histological type was diagnosed based on lesion color in WLE, surface patterns (pit, villi, and unclear) and vascular irregularities in NBI-ME, and surface patterns in NBI-AA. Results Histological types of target areas were differentiated adenocarcinoma and undifferentiated adenocarcinoma in 206 and 15 cases, respectively. Diagnostic accuracy of WLE, NBI-ME, and NBI-AA for the histological type was 96.4 % (213/221), 96.8 % (214/221), and 95.5 % (211/221), respectively. No significant differences were observed among modalities. Positive predictive value based on endoscopic findings in NBI-ME was 98.0 % (149/152) for the villi pattern, 100 % (19/19) for the irregular pit pattern, 100 % (9/9) for the unclear surface pattern with a vascular network, 90.3 % (28/31) for the unclear surface pattern with mild vascular irregularity, and 88.9 % (8/9) for the unclear surface pattern with severe vascular irregularity. Conclusions NBI-ME and NBI-AA did not show any advantages over WLE for diagnostic accuracy. Villi pattern, irregular pit pattern, and vascular network may be useful for identifying differentiated adenocarcinoma.

Loss of Tyrosine Kinase 2 Does Not Affect the Severity of Jak2V617F-induced Murine Myeloproliferative Neoplasm.

BACKGROUND/AIM: In myeloproliferative neoplasms (MPN), Janus kinase 2 (JAK2) is activated by mutations including JAK2V617F (JAK2VF). It is unclear whether JAK kinases [i.e. JAK1, JAK2, JAK3, or tyrosine kinase 2 (TYK2)] other than JAK2 have cooperative actions such as enhancement or suppression of JAK2. If other kinases enhance activation, therapies that co-target them could have a therapeutic efficacy. We examined the role of TYK2 in Jak2VF-induced murine MPN. MATERIALS AND METHODS: We crossed Jak2VF transgenic mice and Tyk2-knockout (Tyk2KO) mice to generate Jak2VF/Tyk2KO mice. The disease severity and treatment effect with a JAK2 inhibitor was compared between Jak2VF and Jak2VF/Tyk2KO mice. RESULTS: Both types of mice developed MPN, and there were no differences in peripheral blood counts, spleen weight, or survival period. Upon JAK2 inhibitor therapy, both types of mice had equally improved leukocytosis and splenomegaly. CONCLUSION: TYK2 does not have cooperative effects with JAK2VF upon MPN onset nor in the presence of a JAK2 inhibitor.

TET2 mutation in diffuse large B-cell lymphoma.

Ten-eleven translocation-2 (TET2) mutation is frequently observed in myeloid malignancies, and loss-of-function of TET2 is essential for the initiation of malignant hematopoiesis. TET2 mutation presents across disease entities and was reported in lymphoid malignancies. We investigated TET2 mutations in 27 diffuse large B-cell lymphoma (DLBCL) patients and found a frameshift mutation in 1 case (3.7%). TET2 mutation occurred in some populations of DLBCL patients and was likely involved in the pathogenesis of their malignancies.

Surrounding Gastric Mucosa Findings Facilitate Diagnosis of Gastric Neoplasm as Gastric Adenoma or Early Gastric Cancer.

Background and Aim. It is difficult to master the skill of discriminating gastric adenoma from early gastric cancer by conventional endoscopy or magnifying endoscopy combined with narrow-band imaging, because the colors and morphologies of these neoplasms are occasionally similar. We focused on the surrounding gastric mucosa findings in order to determine how to discriminate between early gastric cancer and gastric adenoma by analyzing the characteristics of the gastric background mucosa. Methods. We retrospectively examined 146 patients who underwent endoscopic submucosal dissection for gastric neoplasm between October 2009 and January 2015. The boundary of atrophic gastritis was classified endoscopically according to the Kimura-Takemoto classification system. Of 146 lesions, 63 early gastric cancers and 21 gastric adenomas were ultimately evaluated and assessed. Results. Almost all gastric adenomas were accompanied by open-type gastritis, whereas 47 and 16 early gastric cancers were accompanied by open-type and closed-type gastritis, respectively (p = 0.037). Conclusions. The evaluation of the boundary of atrophic gastritis associated with gastric neoplasms appears to be useful for discrimination between early gastric cancer and gastric adenoma. When gastric neoplasm is present in the context of surrounding localized gastric atrophy, gastric cancer is probable but not certain.

Gene expression profiling of loss of TET2 and/or JAK2V617F mutant hematopoietic stem cells from mouse models of myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPNs) are clinically characterized by the chronic overproduction of differentiated peripheral blood cells and the gradual expansion of malignant intramedullary/extramedullary hematopoiesis. In MPNs mutations in JAK2 MPL or CALR are detected mutually exclusive in more than 90% of cases [1,2]. Mutations in them lead to the abnormal activation of JAK/STAT signaling and the autonomous growth of differentiated cells therefore they are considered as "driver" gene mutations. In addition to the above driver gene mutations mutations in epigenetic regulators such as TET2 DNMT3A ASXL1 EZH2 or IDH1/2 are detected in about 5%-30% of cases respectively [3]. Mutations in TET2 DNMT3A EZH2 or IDH1/2 commonly confer the increased self-renewal capacity on normal hematopoietic stem cells (HSCs) but they do not lead to the autonomous growth of differentiated cells and only exhibit subtle clinical phenotypes [4,6-8,5]. It was unclear how mutations in such epigenetic regulators influenced abnormal HSCs with driver gene mutations how they influenced the disease phenotype or whether a single driver gene mutation was sufficient for the initiation of human MPNs. Therefore we focused on JAK2V617F and loss of TET2-the former as a representative of driver gene mutations and the latter as a representative of mutations in epigenetic regulators-and examined the influence of single or double mutations on HSCs (Lineage(-)Sca-1(+)c-Kit(+) cells (LSKs)) by functional analyses and microarray whole-genome expression analyses [9]. Gene expression profiling showed that the HSC fingerprint genes [10] was statistically equally enriched in TET2-knockdown-LSKs but negatively enriched in JAK2V617F-LSKs compared to that in wild-type-LSKs. Double-mutant-LSKs showed the same tendency as JAK2V617F-LSKs in terms of their HSC fingerprint genes but the expression of individual genes differed between the two groups. Among 245 HSC fingerprint genes 100 were more highly expressed in double-mutant-LSKs than in JAK2V617F-LSKs. These altered gene expressions might partly explain the mechanisms of initiation and progression of MPNs which was observed in the functional analyses [9]. Here we describe gene expression profiles deposited at the Gene Expression Omnibus (GEO) under the accession number GSE62302 including experimental methods and quality control analyses.

Loss of TET2 has dual roles in murine myeloproliferative neoplasms: disease sustainer and disease accelerator.

Acquired mutations of JAK2 and TET2 are frequent in myeloproliferative neoplasms (MPNs). We examined the individual and cooperative effects of these mutations on MPN development. Recipients of JAK2V617F cells developed primary myelofibrosis-like features; the addition of loss of TET2 worsened this JAK2V617F-induced disease, causing prolonged leukocytosis, splenomegaly, extramedullary hematopoiesis, and modestly shorter survival. Double-mutant (JAK2V617F plus loss of TET2) myeloid cells were more likely to be in a proliferative state than JAK2V617F single-mutant myeloid cells. In a serial competitive transplantation assay, JAK2V617F cells resulted in decreased chimerism in the second recipients, which did not develop MPNs. In marked contrast, cooperation between JAK2V617F and loss of TET2 developed and maintained MPNs in the second recipients by compensating for impaired hematopoietic stem cell (HSC) functioning. In-vitro sequential colony formation assays also supported the observation that JAK2V617F did not maintain HSC functioning over the long-term, but concurrent loss of TET2 mutation restored it. Transcriptional profiling revealed that loss of TET2 affected the expression of many HSC signature genes. We conclude that loss of TET2 has two different roles in MPNs: disease accelerator and disease initiator and sustainer in combination with JAK2V617F.

TET2 Mutation in Adult T-Cell Leukemia/Lymphoma.

Loss-of-function of ten-eleven translocation-2 (TET2) is a common event in myeloid malignancies, and plays pleiotropic roles, including augmenting stem cell self-renewal and skewing hematopoietic cells to the myeloid lineage. TET2 mutation has also been reported in lymphoid malignancies; 5.7～12% of diffuse large B-cell lymphomas and 18～83% of angioimmunoblastic T-cell lymphomas had TET2 mutations. We investigated TET2 mutations in 22 adult T-cell leukemia/lymphoma (ATLL) patients and identified a missense mutation in 3 cases (14%). TET2 mutation occurred in a number of ATLL patients and was likely involved in their leukemogenesis.

[A case report of gastrointestinal stromal tumor of the small intestine presenting with liver abscesses caused by Streptococcus constellatus].

A 49-year-old woman visited a local hospital in October 2007 with complaint of fever and melena. Abdominal ultrasonography and abdominal computed tomography revealed an irregular mass in the lower abdomen, together with multiple masses in the liver. She was admitted because of anemia, and the high fever was determined to be an inflammatory response. Blood tests revealed elevated biliary enzyme levels. Percutaneous biopsy of the liver mass was performed, which revealed liver abscesses caused by Streptococcus constellatus. On abdominal angiography, the mass was suspected to be a tumor of the small intestine. In late November 2007, laparoscopy-assisted partial small bowel resection was performed, and pathological examination of the surgical specimen confirmed gastrointestinal stromal tumor (GIST) of the small bowel. Because reports of small intestinal GIST with liver abscesses caused by Streptococcus constellatus are rare, this case description could provide valuable information.