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Robot-assisted surgery for congenital biliary dilatation has been evolving primarily with the da Vinci® Surgical System. The hinotori™ Surgical Robot System, developed in Japan, received approval for gastroenterological surgery in 2022. We present the inaugural case of congenital biliary dilatation surgery utilizing the hinotori™ system. A 57-year-old woman was referred to our institution for evaluation and treatment of common bile duct dilatation classified under Todani Type Ia congenital biliary dilatation. Robotic resection of the extrahepatic bile duct and hepaticojejunostomy with Roux-en-Y were performed. The operation lasted 292 min with minimal blood loss (10 mL). The patient had an uneventful postoperative course and was discharged 10 days after surgery. Robotic surgery using the hinotori™ system for congenital biliary dilatation can be safely performed., (© 2024 Asia Endosurgery Task Force and Japan Society of Endoscopic Surgery and John Wiley & Sons Australia, Ltd.)

Background: Pancreatic ductal occlusion can accompany pancreatic head cancer, leading to pancreatic exocrine insufficiency (PEI) and adverse effects on nutritional status and postoperative outcomes. We investigated its impact on nutritional status, body composition, and postoperative outcomes in patients with pancreatic head cancer undergoing neoadjuvant therapy (NAT)., Methods: We analyzed 136 patients with pancreatic head cancer who underwent NAT prior to intended pancreaticoduodenectomy (PD) between 2015 and 2022. Nutritional and anthropometric indices (body mass index [BMI], albumin, prognostic nutritional index [PNI], Glasgow prognostic score, psoas muscle index, subcutaneous adipose tissue index [SATI], and visceral adipose tissue index) and postoperative outcomes were compared between the occlusion (n = 78) and non-occlusion (n = 58) groups, in which 61 and 44 patients, respectively, ultimately underwent PD., Results: The occlusion group showed significantly lower post-NAT BMI, PNI, and SATI (p = 0.011, 0.005, and 0.015, respectively) in the PD cohort. The occlusion group showed significantly larger main pancreatic duct, smaller pancreatic parenchyma, and greater duct-parenchymal ratio (p < 0.001), and these morphological parameters significantly correlating with post-NAT nutritional and anthropometric indices. Postoperative 3-year survival and recurrence-free survival (RFS) rates were significantly poorer (p = 0.004 and 0.013) with pancreatic ductal occlusion, also identified as an independent postoperative risk factor for overall survival (hazard ratio [HR]: 2.31, 95% confidence interval [CI] 1.08-4.94, p = 0.030) and RFS (HR: 2.03, 95% CI 1.10-3.72, p = 0.023), in multivariate analysis., Conclusions: Pancreatic ductal occlusion may be linked to poorer postoperative outcomes due to PEI-related malnutrition., (© 2024. The Author(s).)

Objective: Krüppel-like transcription factor 4(KLF4) mutations are more frequently observed in low-grade lesions than in high-grade lesions of intraductal papillary mucinous neoplasms (IPMN) of the pancreas. However, the role of KLF4 mutations in IPMNs with concomitant pancreatic ductal adenocarcinoma (PDAC) remains unclear. This study clarified the rate and effect of KLF4 mutations in IPMN with concomitant PDAC., Methods: DNA was extracted from 65 formalin-fixed and paraffin-embedded samples from 52 patients including 13 IPMN with concomitant PDAC and 39 IPMN alone. A comprehensive screening was performed using next-generation sequencing (NGS) for the 5 IPMNs with concomitant PDAC and 5 IPMNs alone, followed by targeted sequencing for KLF4, GNAS, and KRAS mutations., Results: In NGS screening, KRAS mutations were observed in all samples except for one, GNAS mutation in two IPMNs with concomitant PDAC, and a KLF4 mutation in one IPMN with concomitant PDAC. Targeted sequence detected KLF4 mutations in 11 of the 52 IPMNs. Concomitant PDAC developed only in the non-intestinal, non-invasive, and branch duct IPMN cases, and KLF4 mutations were more frequent in this IPMN type than in the other type (36% vs. 10%, p = 0.04). For this IPMN type with KLF4 mutation, PDAC-prediction sensitivity, specificity, and accuracy were 63%, 82%, and 79%, respectively., Conclusion: For selected IPMNs with non-intestinal, non-invasive, and branch duct, genetic assessment might be a helpful tool for predicting the possible development of concomitant PDAC, although a prospective validation study using a larger study population is needed., Competing Interests: Conflicts of Interest and Source of Funding: The authors declare no conflicts of interest related to this article. This study was funded by Grant-in-Aid for Scientific Research (KAKEN) (20H03753, 22K16514, 22K19567, 23H02984)., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Surgical resection is standard treatment for invasive intraductal papillary mucinous carcinoma (IPMC); however, impact of multidisciplinary treatment on survival including postoperative adjuvant therapy (AT), neoadjuvant therapy (NAT), and treatment for recurrent lesions is unclear. We investigated the effectiveness of multidisciplinary treatment in prolonging survival of patients with invasive IPMC., Methods: This retrospective multi-institutional study included 1183 patients with invasive IPMC undergoing surgery at 40 academic institutions. We analyzed the effects of AT, NAT, and treatment for recurrence on survival of patients with invasive IPMC., Results: Completion of the planned postoperative AT for 6 months improved the overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS) of patients with stage IIB and stage III resected invasive IPMC, elevated preoperative carbohydrate antigen 19-9 level, lymphovascular invasion, perineural invasion, serosal invasion, and lymph node metastasis on un-matched and matched analyses. Of the patients with borderline resectable (BR) invasive IPMC, the OS ( p  = 0.001), DSS ( p  = 0.001), and RFS ( p  = 0.001) of patients undergoing NAT was longer than that of those without on the matched analysis. Of the 484 invasive IPMC patients (40.9%) who developed recurrence after surgery, the OS of 365 patients who received any treatment for recurrence was longer than that of those without treatment (40.6 vs. 22.4 months, p  < 0.001)., Conclusion: Postoperative AT might benefit selected patients with invasive IPMC, especially those at high risk of poor survival. NAT might improve the survivability of BR invasive IPMC. Any treatment for recurrence after surgery for invasive IPMC might improve survival., Competing Interests: Author SH was supported by grants from the Japan Pancreas Society. Author MU was supported by grants from Taiho Pharma, however, the funding source had no role in the design, practice, or analysis of this study. Author SS was supported by grants from Nihon Servier, Amino‐Up co, however, the funding source had no role in the design, practice, or analysis of this study. Authors HN, KH, and HY are editorial board members of Annals of Gastroenterological Surgery. Authors SH, IE, and AH are associate editors of Annals of Gastroenterological Surgery., (© 2024 The Authors. Annals of Gastroenterological Surgery published by John Wiley & Sons Australia, Ltd on behalf of The Japanese Society of Gastroenterological Surgery.)

Most surgeons perform laparoscopic left lateral sectionectomy (Lap LLS) using the caudo-peripheral approach (C-P approach). However, recently, a cranio-dorsal approach (C-D approach) has been applied to various types of hepatectomy owing to its advantage of preventing split injury. No studies yet have compared the perioperative outcomes of Lap LLS using each approach. Therefore, this study aimed to determine whether the C-D approach is useful for Lap LLS by comparing its perioperative outcomes with the C-P approach. Data of patients who underwent Lap LLS in our institution between 2010 and 2022 for liver tumors were retrospectively collected. We compared the perioperative outcomes of Lap LLS using a conventional C-P approach, which transects hepatic parenchyma in the caudo-peripheral direction and a C-D approach, which transects hepatic parenchyma in the cranio-caudal direction. All surgeries were performed only by board-certified expert surgeons to minimize technical bias. Furthermore, the perioperative procedures employed at our institution remained unchanged throughout the study period. A total of 36 patients were included in the study (C-P approach, n = 25; C-D approach, n = 11). The C-D approach showed a significantly shorter operation time than the C-P approach (median, 225 min vs. 262 min, p = 0.04). In addition, the C-D approach showed significantly lower blood loss than the C-P approach (median, 20 mL vs. 100 mL, p < 0.01). Other parameters, such as morbidity and hospital stay, were comparable between groups. The C-D approach could offer better surgical outcomes than the conventional C-P approach., (© 2023. Italian Society of Surgery (SIC).)

Coronin proteins are actin-related proteins containing WD repeat domains encoded by seven genes ( CORO1A , CORO1B , CORO1C , CORO2A , CORO2B , CORO6 , and CORO7 ) in the human genome. Analysis of large cohort data from The Cancer Genome Atlas revealed that expression of CORO1A , CORO1B , CORO1C , CORO2A , and CORO7 was significantly upregulated in pancreatic ductal adenocarcinoma (PDAC) tissues ( p < 0.05). Moreover, high expression of CORO1C and CORO2A significantly predicted the 5 year survival rate of patients with PDAC ( p = 0.0071 and p = 0.0389, respectively). In this study, we focused on CORO1C and investigated its functional significance and epigenetic regulation in PDAC cells. Knockdown assays using siRNAs targeting CORO1C were performed in PDAC cells. Aggressive cancer cell phenotypes, especially cancer cell migration and invasion, were inhibited by CORO1C knockdown. The involvement of microRNAs (miRNAs) is a molecular mechanism underlying the aberrant expression of cancer-related genes in cancer cells. Our in silico analysis revealed that five miRNAs ( miR-26a-5p , miR-29c-3p , miR-130b-5p , miR-148a-5p , and miR-217 ) are putative candidate miRNAs regulating CORO1C expression in PDAC cells. Importantly, all five miRNAs exhibited tumor-suppressive functions and four miRNAs except miR-130b-5p negatively regulated CORO1C expression in PDAC cells. CORO1C and its downstream signaling molecules are potential therapeutic targets in PDAC.

Background: Microbiota have been reported to influence the development of various gastrointestinal neoplasms through the mechanism of sustained inflammation; however, few data are available regarding their influence on intraductal papillary mucinous neoplasms. The aim of this study was to assess the association between specific microbiota and the clinicopathologic characteristics of intraductal papillary mucinous neoplasms of the pancreas., Methods: DNA was extracted from formalin-fixed, paraffin-embedded samples of 30 patients who underwent pancreatectomy for intraductal papillary mucinous neoplasm, and polymerase chain reaction was used to create sequence libraries using the primer set for the V3 and V4 region of 16S recombinant DNA. Filtered sequence reads were then processed into operational taxonomic units with a 97% identity threshold and the relative abundance of bacteria compared between the 2 groups using operational taxonomic units., Results: There was a trend toward fewer Firmicutes and more Proteobacteria and Fusobacteria in the relative abundance of main duct operational taxonomic units than in branch duct operational taxonomic units. The relative abundances of Bacteroidetes (P < .01) and Fusobacteria (P = .04) were significantly higher in invasive intraductal papillary mucinous neoplasms than in noninvasive intraductal papillary mucinous neoplasms. The relative abundance of the intestinal type was significantly lower in Firmicutes than the relative abundance of the nonintestinal type (P = .04). Notably, main duct operational taxonomic units with the intestinal subtype were affected by increased proportions of Proteobacteria and Fusobacteria, and Fusobacteria were abundant in the intestinal type of invasive main duct operational taxonomic units., Conclusion: Intratumoral microbiota may be involved in the progression of operational taxonomic units., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Patients diagnosed with resectable pancreatic ductal adenocarcinoma often experience early recurrence even after upfront R0 resection. This study aimed to define early recurrence and identify preoperative risk factors for early recurrence after upfront pancreaticoduodenectomy in patients with resectable pancreatic ductal adenocarcinoma of the pancreatic head., Methods: This multicenter, retrospective study involved 500 patients who underwent pancreaticoduodenectomy resectable pancreatic ductal adenocarcinoma of the pancreatic head at 10 institutions between 2007 and 2016. Preoperative, intraoperative, and postoperative clinicopathological results were compared between early and non-early recurrence groups. Predictors of early recurrence were determined using statistical analyses., Results: Log-rank tests revealed a significant difference (P < .001) between recurrence within 3 to 6 months and 6 to 9 months. Early recurrence was subsequently defined as recurrence within 6 months. Patients were categorized into early recurrence (n = 104) and non-early recurrence groups (n = 389). The median overall survival of the early and non-early recurrence groups was 8.6 months and 42.6 months (P < .001), respectively. Preoperatively, high carbohydrate antigen 19-9 levels ≥120 U/mL, retroperitoneal invasion, and diabetes mellitus were identified as independent predictive risk factors for early recurrence according to multivariate analysis. Comparing survival rates among patients with 3, 2, 1, or none of these factors, the median overall survival was 17.6 (n = 90), 21.2 (n = 184), 47 (n = 141), and 61.5 (n = 73) months, respectively., Conclusion: The optimal period that defines the early recurrence for resectable pancreatic ductal adenocarcinoma of the pancreatic head is 6 months. Tumor size ≥20 mm, preoperative carbohydrate antigen 19-9 levels ≥120 U/mL, retroperitoneal invasion of the tumor, and the presence of diabetes mellitus are independently associated with early recurrence., (Copyright © 2022 Elsevier Inc. All rights reserved.)

We recently determined the RNA sequencing-based microRNA (miRNA) expression signature of colorectal cancer (CRC). Analysis of the signature showed that the expression of both strands of pre- miR-139 ( miR-139-5p , the guide strand, and miR-139-3p , the passenger strand) was significantly reduced in CRC tissues. Transient transfection assays revealed that expression of miR-139-3p blocked cancer cell malignant transformation (e.g., cell proliferation, migration, and invasion). Notably, expression of miR-139-3p markedly blocked RAC-alpha serine/threonine-protein kinase (AKT) phosphorylation in CRC cells. A combination of in silico database and gene expression analyses of miR-139-3p -transfected cells revealed 29 putative targets regulated by miR-139-3p in CRC cells. RNA immunoprecipitation analysis using an Argonaute2 (AGO2) antibody revealed that KRT80 was efficiently incorporated into the RNA-induced silencing complex. Aberrant expression of Keratin 80 ( KRT80 ) was detected in CRC clinical specimens by immunostaining. A knockdown assay using small interfering RNA (siRNA) targeting KRT80 showed that reducing KRT80 expression suppressed the malignant transformation (cancer cell migration and invasion) of CRC cells. Importantly, inhibiting KRT80 expression reduced AKT phosphorylation in CRC cells. Moreover, hexokinase-2 (HK2) expression was reduced in cells transfected with the KRT80 siRNAs or miR-139-3p . The involvement of miRNA passenger strands (e.g., miR-139-3p ) in CRC cells is a new concept in miRNA studies. Our tumor-suppressive miRNA-based approach helps elucidate the molecular pathogenesis of CRC.

Background: By examining skeletal muscle catabolism, we aimed to investigate whether laparoscopic left lateral sectionectomy (LLS) is less invasive compared with the open approach., Methods: The psoas muscle index (PMI) was measured using computed tomography images before and after surgery. We assessed the relationship between the perioperative PMI reduction rate and the estimation of physiologic ability and surgical stress (E-PASS) score and then compared the PMI reduction rates associated with different approaches., Results: Of the 31 patients, 13 and 18 underwent the open and laparoscopic approaches, respectively. A strong correlation was observed between the PMI reduction rates and surgical stress scores (SSS) ( r =0.561, P <0.01). The laparoscopic approach was associated with a significantly lower PMI reduction rate ( P <0.01) and SSS ( P <0.01) than the open approach., Conclusion: Laparoscopic LLS should be less invasive than the open approach from the perspective of not only perioperative outcomes but also skeletal muscle catabolism., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background/aim: The development and application of cancer immunotherapy to pancreatic cancer has not progressed because its efficacy has not been proven in clinical trials. In this study, we aimed to explore potential targets of immune checkpoint inhibitor therapy for pancreatic cancer treatment., Materials and Methods: We collected resected specimens from 40 patients with pancreatic cancer who underwent resection at our Institution without any preoperative treatment. We evaluated the expression of molecules in the programmed death receptor-1 (PD-1), T cell immunoglobulin mucin-3 (Tim-3)/Galectin-9, and CD155/T cell immunoreceptor with Ig and ITIM domains (TIGIT) pathways using immunohistochemical staining. The correlation between the expression pattern of these molecules and patient prognosis were assessed using Kaplan-Meier analysis., Results: An increased number of CD8 + T cells in pancreatic cancer tissue was significantly associated with a better patient prognosis. Additionally, patients with a higher ratio of PD-1 expression to CD8 + T cells had a worse prognosis. We observed no correlation between the Tim-3/Galectin-9 and CD155/TIGIT pathways and patient prognosis., Conclusion: Modifications in the immune environment to increase T cell infiltration into tumors could result in the PD-1 pathway becoming a potential target to treat pancreatic cancer using immune checkpoint inhibition., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Lymphatic metastasis is a major route of metastasis in distal cholangiocarcinoma (DCC). The present study aimed to elucidate the pattern of lymph node (LN) metastasis and the effectiveness of LN dissection and postoperative adjuvant chemotherapy in patients with DCC., Methods: Patients who underwent surgical resection with curative intent for DCC were enrolled. The nomenclature of the LN stations was defined according to the Japanese Society of Hepato-Biliary-Pancreatic Surgery guidelines. Effectiveness of LN dissection of each station was calculated using frequency of LN metastasis to the station and 5-year survival rate of patients with LN metastasis to that station., Results: Of the 105 patients included in the study, 46 (43.8%) had LN metastasis, and 43 (41.0%) underwent postoperative adjuvant therapy. LN metastasis, serum carbohydrate antigen (CA) 19-9 level > 37 U/mL, and positive bile duct margin were independent risk factors for shorter overall survival (OS). The most common metastatic LN station at surgery was No. 13 (32.7%), followed by No. 12 (19.2%), No. 17 (9.6%), and No. 8 (6.6%). There was no effectiveness of LN dissection of the station No. 8, 14, and 16. Adjuvant chemotherapy was significantly associated with longer OS in patients with LN metastasis but not in those with positive ductal margins or serum CA 19-9 level > 37 U/mL., Conclusions: Postoperative adjuvant chemotherapy was associated with a better prognosis in patients with DCC and LN metastasis. However, a more effective therapeutic strategy is required to improve the prognosis of patients with other negative prognostic factors., (© 2022. The Author(s) under exclusive licence to Japan Society of Clinical Oncology.)

Background: Locoregional recurrence and metastasis to the liver, peritoneum, and lung are the most common recurrent patterns of pancreatic ductal adenocarcinoma (PDAC) after radical resection. Recurrence in the abdominal wall is extremely rare. Herein, we report our experience with a patient who had recurrent PDAC in the abdominal wall with long-term survival by means of multidisciplinary therapy., Case Presentation: A 76-year-old Japanese woman was diagnosed with resectable pancreatic tail cancer. She underwent distal pancreatectomy with regional lymphadenectomy after two cycles of gemcitabine plus S-1 as neoadjuvant therapy. She also received eight cycles of S-1 as adjuvant chemotherapy. Approximately 14 months after the initial surgery, imaging examinations identified a mass suggesting recurrence in the abdominal wall at the middle wound that involved the transverse colon. After two cycles of gemcitabine plus nab-paclitaxel, chemoradiotherapy (S-1 plus 45 Gy) and seven cycles of modified FOLFIRINOX (5-fluorouracil/leucovorin, irinotecan, and oxaliplatin) were administered. The patient did not develop any new recurrent lesions during chemotherapy and chemoradiotherapy. Therefore, the recurrent lesion in the abdominal wall and the involved transverse colon were resected. We confirmed the lack of peritoneal dissemination during surgery. Pathological examination revealed that the resected lesion was metastasis of primary PDAC, and the surgical margin was 1 mm. However, re-recurrence localized in the abdominal wall was detected 9 months later. The re-recurrent lesion was diagnosed as local recurrence of the first recurrent lesion. We performed a second resection of the abdominal wall using a femoral myocutaneous flap to achieve sufficient surgical margin. The pathological findings of the resected specimen were the same as those of the previous specimens, and the resection margin was negative. The patient's postoperative course was uneventful. Seven years after the initial surgery and 3 years and 7 months after the third surgery, the patient is alive with no signs of recurrence., Conclusions: Long-term survival could be achieved by radical resection with sufficient surgical margins for recurrence of PDAC in the abdominal wall if new other recurrent lesions, including peritoneal dissemination, are prevented through chemotherapy., (© 2022. The Author(s).)

Background: Solid pseudopapillary neoplasm (SPN) is a rare pancreatic tumor that predominantly affects young females. Prognosis is excellent; however, 10-15% of patients show metastasis at the time of surgery or develop tumor recurrence after pancreatectomy., Case Presentation: We reviewed the clinical course of three patients with advanced or recurrent SPN and subsequently underwent multidisciplinary treatment at our institution between 2002 and 2019. The primary tumor was resected in all three patients, and metastases were also resected if indicated. Intensive combined therapy, including re-resection, chemotherapy, ablation, arterial chemoembolization, and radiation therapy, allowed all patients to survive for a long time. The literature review showed that resection seems to be more effective than other treatments for metastatic SPN., Conclusions: Multidisciplinary treatment, including resection, may improve the prognosis of patients with SPN with recurrence or metastasis., (© 2022. The Author(s).)

Background: Hepatocellular carcinoma (HCC) patients with metastases to the cervical lymph nodes are extremely rare, and its clinical course is characterized by rapidly progressive disease. Hence, there have been no reports of metastatic cervical lymph node recurrence indicated after a long postoperative surveillance period., Case Presentation: The patient was a 63-year-old male who underwent right hepatectomy for HCC of the right upper lobe. Three years after resection, metastatic lymph node recurrence was detected in the subdiaphragm, superior mediastinum, and right cervical lymph nodes. The patient underwent excisional biopsy of the cervical lymph node, followed by molecular-targeted therapy and radiation therapy. Lenvatinib reduced the size of all metastatic lymph nodes and the patient survived for a relatively long period of 43 months after the recurrence was detected., Conclusions: After resection of HCC in the right upper lobe, there is the possibility of metastatic lymph node recurrence in unusual sites, including the cervical region, and lenvatinib may be effective in those recurrences., (© 2021. The Author(s).)

Background/aim: Our recent miRNA analyses revealed that miR-30a-5p has tumor-suppressive activity in pancreatic ductal adenocarcinoma (PDAC). Herein, we sought to identify tumor-suppressive genes controlled by miR-30a-5p, emphasizing on genes that are closely involved in the molecular pathogenesis of PDAC. We uncovered several novel findings regarding the pathogenesis of this disease., Materials and Methods: In silico analyses were used to identify the putative target genes of miR-30a-5p and assess their expression levels. Direct regulation of RRM2 by miR-30a-5p and its oncogenic functions were evaluated in PDAC cell lines. Overexpression of RRM2 was demonstrated in clinical samples., Results: A total of 24 putative targets were identified by in silico database analysis. High expression of 4 genes (CBFB, RRM2, AHNAK, and DCBLD1) was significantly associated with shorter survival of patients with PDAC. Functional assays demonstrated that knockdown of RRM2 attenuated the malignant phenotype of PDAC cells., Conclusion: The miR-30a-5p/RRM2 axis facilitated the malignant transformation of PDAC cells., (Copyright © 2021 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Purpose: Neoadjuvant therapy (NAT) is used to treat not only advanced pancreatic cancer but also resectable lesions. The present study investigated the effectiveness of postoperative adjuvant chemotherapy for patients with pancreatic cancer who underwent surgical resection after NAT., Methods: Patients who underwent macroscopically curative resection after NAT for pancreatic cancer were enrolled. Adjuvant chemotherapy was defined as at least 1 cycle of planned chemotherapy within 3 months after the date of surgery and included S-1, gemcitabine, or both. We retrospectively examined the effect of adjuvant chemotherapy on overall survival (OS) and recurrence-free survival (RFS) as a function of patients' clinicopathological factors., Results: Ninety-seven patients were included in the study, of which 68 (70.1%) underwent adjuvant chemotherapy. Administration of adjuvant chemotherapy was significantly associated with prolonged OS and RFS in patients whose elevated levels of carbohydrate antigen 19-9 or duke pancreatic monoclonal antigen type-2 did not normalize after NAT. In patients with pathological lymph node metastasis, the administration of adjuvant chemotherapy was significantly associated with longer OS but did not improve PFS., Conclusions: Postoperative adjuvant chemotherapy was associated with prolonged postoperative survival in patients with pancreatic cancer who did not sufficiently respond to NAT as judged by tumor marker expression., (© 2021. Society of Surgical Oncology.)

The diagnostic value of 18 F-fluorodeoxyglucose (FDG) uptake in the management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas remains unclear. This study aimed to assess the role of FDG uptake in the diagnosis of different degrees of dysplasia of IPMNs. We retrospectively analyzed the following three points in 84 patients with IPMNs: (1) risk factors to predict high-grade dysplasia (HGD) and invasive carcinoma (INV); (2) the relationship between FDG uptake and glucose transporter 1 (GLUT-1) expression; and (3) the relationship between FDG uptake and the presence of mural nodules. The histopathological diagnosis was low-grade dysplasia (LGD) in 43 patients, HGD in 16, and INV in 25. The maximum standardized uptake value (SUV-max) was significantly higher in INV than in LGD/HGD ( p < 0.0001, p = 0.0136). The sensitivity and specificity to discriminate INV from LGD/HGD were 80.0% and 86.2%, respectively, using the receiver operator characteristic curve, when the optimal cutoff score of SUV-max was set at 4.03. Those values were not different between HGD and LGD. More than half of HGD patients had low GLUT-1 expression. Taken together, FDG-PET/CT is useful in distinguishing between non-invasive and invasive IPMN. Our results offer critical information that may determine surgical treatment strategies.

To elucidate novel aspects of the molecular pathogenesis of colorectal cancer (CRC), we have created a new microRNA (miRNA) expression signature based on RNA-sequencing. Analysis of the signature showed that 84 miRNAs were upregulated, and 70 were downregulated in CRC tissues. Interestingly, our signature indicated that both guide and passenger strands of some miRNAs were significantly dysregulated in CRC tissues. These findings support our earlier data demonstrating the involvement of miRNA passenger strands in cancer pathogenesis. Our study focused on downregulated miR-490-3p and investigated its tumor-suppressive function in CRC cells. We successfully identified a total of 38 putative oncogenic targets regulated by miR-490-3p in CRC cells. Among these targets, the expression of three genes ( IRAK1 : p = 0.0427, FUT1 : p = 0.0468, and GPRIN2 : p = 0.0080) significantly predicted 5-year overall survival of CRC patients. Moreover, we analyzed the direct regulation of IRAK1 by miR-490-3p , and its resultant oncogenic function in CRC cells. Thus, we have clarified a part of the molecular pathway of CRC based on the action of tumor-suppressive miR-490-3p . This new miRNA expression signature of CRC will be a useful tool for elucidating new molecular pathogenesis in this disease.

Background: Creating a good surgical visual field is one of the most important factors for performing a successful surgery. Here, we introduce a useful technique for creating a good liver parenchymal visual transection plane during laparoscopic partial hepatectomy and compare the perioperative outcomes of our current technique with those of conventional techniques., Methods: We reviewed the data of patients who underwent laparoscopic partial hepatectomy between July 2016 and December 2020. The current technique for creating transection planes was first applied in our department in April 2019. The patients were divided into conventional (forceps) and current (silicone ring) technique groups, depending on the surgical technique., Results: Twenty-eight and 12 patients underwent laparoscopic partial hepatectomy using the conventional and current techniques, respectively, when the difficulty level-as determined by IWATE criteria-was low. Although the tumor size was significantly larger (median: 22.5 vs. 15 mm, P=0.04) in the current technique group, the estimated intraoperative blood loss was significantly lower (median: 50 vs. 100 mL, P=0.01), and the median surgical margin was significantly longer (median: 7 vs. 3 mm, P=0.02). There were no significant between-group differences in surgical time (median: 344 vs. 240 min, P=0.14), postoperative hospital stay duration (median: 11 vs. 9.5 d, P=0.051), and the incidence of complications (P=0.63)., Conclusion: We believe that the technique involving the use of a silicone ring can result in better surgical outcomes as it provides a good visual hepatic transection plane during laparoscopic partial hepatectomy., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

The aggressive nature of intrahepatic cholangiocarcinoma (ICC) renders it a particularly lethal solid tumor. Searching for therapeutic targets for ICC is an essential challenge in the development of an effective treatment strategy. Our previous studies showed that the miR-29-3p -family members ( miR-29a-3p , miR-29b-3p and miR-29c-3p ) are key tumor-suppressive microRNAs that control many oncogenic genes/pathways in several cancers. In this study, we searched for therapeutic targets for ICC using the miR-29-3p -family as a starting point. Our functional studies of cell proliferation, migration and invasion confirmed that the miR-29-3p -family act as tumor-suppressors in ICC cells. Moreover, in silico analysis revealed that "focal adhesion", "ECM-receptor", "endocytosis", "PI3K-Akt signaling" and "Hippo signaling" were involved in oncogenic pathways in ICC cells. Our analysis focused on the genes for integrin-α6 ( ITGA6 ) and integrin-β1 ( ITGB1 ), which are involved in multiple pathways. Overexpression of ITGA6 and ITGB1 enhanced malignant transformation of ICC cells. Both ITGA6 and ITGB1 were directly regulated by the miR-29-3p -family in ICC cells. Interestingly, expression of ITGA6 / ITGB1 was positively controlled by the transcription factor SP1, and SP1 was negatively controlled by the miR-29-3p -family. Downregulation of the miR-29-3p -family enhanced SP1 -mediated ITGA6 / ITGB1 expression in ICC cells. MicroRNA-based exploration is an attractive strategy for identifying therapeutic targets for ICC.

Background: Unresectable pancreatic ductal adenocarcinoma (UR-PDAC) has a poor prognosis. Conversion surgery is considered a promising strategy for improving the prognosis of UR-PDAC. This study aimed to investigate the clinical benefits of conversion surgery in patients with UR-PDAC., Methods: We retrospectively evaluated patients with PDAC who were referred to our department for possible surgical resection between January 2006 and December 2019. Conversion surgery was performed only in patients with UR-PDAC who could expect R0 resection. We analyzed the prognostic factors for overall survival among patients who underwent conversion surgery., Results: Overall, 638 patients with advanced pancreatic cancer were enrolled in this study. According to resectability, resectable cancer (R) was present in 180 patients, borderline resectable cancer (BR) was present in 60 patients, unresectable locally advanced cancer (UR-LA) was present in 252 patients, and unresectable cancer with distant metastasis (UR-M) was present in 146 patients. Conversion surgery was performed in 20 of the 398 UR cases (5.1%). The median period between the initial therapy and conversion surgery was 15.5 months. According to the Response Evaluation Criteria in Solid Tumors (RECIST) evaluation, the treatment response was CR in one patient, PR in 13, SD in five, and PD in one. Downstaging was pathologically determined in all cases. According to the Evans grading system, grade I was observed in four patients (20%), grade IIb was observed in seven (35%), III was observed in seven (35%), and IV was observed in two (10%). We compared the overall survival period from initial treatment among patients undergoing conversion surgery; the median overall survival durations in the conversion surgery, R, BR, UR-LA, and UR-M groups were 73.7, 32.7, 22.7, 15.7, and 8.8 months, respectively. Multivariate analysis revealed that the presence or absence of chemoradiotherapy (CRT) and the RECIST partial response (PR)/complete response (CR) for the main tumor were statistically significant prognostic factors for overall survival among patients undergoing conversion surgery ( p = 0.004 and 0.03, respectively)., Conclusion: In UR-PDAC, it is important to perform multidisciplinary treatment, including CRT with conversion surgery.

Background: Cholangiolocellular carcinoma (CoCC) is an extremely rare disease comprising less than 1% of all primary malignant liver tumors. No effective treatment other than resection has been established. Herein, we report a case of locally advanced CoCC diagnosed as unresectable, which was successfully treated with curative resection after downsizing chemotherapy., Case Presentation: A 59-year-old Japanese woman with chronic hepatitis B was diagnosed with locally advanced intrahepatic cholangiocellular carcinoma. As it was difficult to perform R0 resection in the local hospital, chemotherapy combined with gemcitabine plus cisplatin was administered every 3 weeks. After a total of 10 courses of chemotherapy over 10 months the tumor was shown to be reduced in size by computed tomography imaging, and she was referred to our department for surgical resection. The effect of chemotherapy was classified as a "partial response" in the response evaluation criteria of solid tumors. After adding one course of chemotherapy, an extended left hepatectomy with resection of the caudate lobe was performed. R0 resection was achieved. Based on the pathological findings, the final diagnosis of CoCC was determined and eight courses of S-1 adjuvant chemotherapy were administered. At 14 months after the operation, the patient was alive without tumor recurrence., Conclusions: Downsizing chemotherapy with gemcitabine and cisplatin may be an effective treatment strategy in locally advanced CoCC. Further evidence is required to establish an optimal strategy for the treatment of locally advanced CoCC.

Background: Mesenteric cysts have various histological forms, including mesenteric cystadenomas and borderline cystic neoplasms. Primary cystadenocarcinoma of the mesentery is extremely rare; therefore, the clinical and radiological features of this tumor have not been fully elucidated., Case Presentation: A 50-year-old Japanese woman had a complaint of a left-sided abdominal distention. Enhanced computed tomography and magnetic resonance imaging revealed a unilocular cystic lesion measuring approximately 10 cm located in the left side of the abdomen. 18 F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) revealed mottled mild FDG uptake in the cyst wall and intense FDG uptake in several mural nodules. The cystic mass with the descending colon was completely removed. Pathological examination of the specimens revealed various histologic patterns of adenocarcinoma, including mucin production in the mural nodules. We eventually diagnosed a primary cystadenocarcinoma arising from the mesentery of the descending colon., Conclusions: Malignancy should be suspected in mesenteric or retroperitoneal cystic tumors with high FDG uptake, and complete resection should be performed with adequate margins.

Aberrantly expressed microRNAs (miRNAs) disrupt intracellular RNA networks and contribute to malignant transformation of cancer cells. Utilizing the latest RNA sequencing technology, we newly created the miRNA expression signature of esophageal squamous cell carcinoma (ESCC). A total of 47 miRNAs were downregulated in ESCC tissues, and these miRNAs were candidates for antitumor miRNAs in ESCC cells. Analysis of the signature revealed that several passenger strands of miRNAs were significantly downregulated in ESCC, e.g., miR-28-3p, miR-30a-3p, miR-30c-3p, miR-133a-3p, miR-139-3p, miR-143-5p, and miR-145-3p. Recent studies indicate that some passenger strands of miRNAs closely involved in cancer pathogenesis. In this study, we focused on both strands of pre-miR-143, and investigated their antitumor roles and target oncogenes in ESCC. Ectopic expression of miR-143-5p and miR-143-3p significantly attenuated malignant phenotypes (e.g., proliferation, migration, and invasive abilities) in ESCC cell lines. We revealed that six genes (HN1, HMGA2, NETO2, STMN1, TCF3, and MET) were putative targets of miR-143-5p regulation, and one gene (KRT80) was a putative target of miR-143-3p regulation in ESCC cells. Our ESCC miRNA signature and analysis strategy provided important insights into the molecular pathogenesis of ESCC.

Background: The clamp crushing method and the use of the Cavitron ultrasonic surgical aspirator (CUSA) are widely accepted techniques for hepatic parenchymal transection. The actuator-driven pulsed water jet (ADPJ) with high tissue selectivity is a new technology that was shown as a safe transection tool in preclinical models, although not much is known about its safety criteria in patients. Therefore, its strongest advantage, the best indications for its use, and its performance in comparison with other transection methods remain to be clarified. In this report, we present several representative cases to help answer these questions., Methods: We started using the ADPJ in December 2017, only in cases where the tumor was very close to major vessels or attached to them, along a considerable length, to preserve vessels and prevent postoperative liver failure. All the cases underwent highly demanding procedures. We avoided using this device in cases such as liver cirrhosis, where the hepatic parenchyma was very hard., Results: Six cases fulfilled our limited indications for using ADPJ. The median age and number of tumors were 55 years (10 to 69 y) and 2.5 years (1 to 4 y), respectively. The mean tumor size was 7.8 cm (2.8 to 21 cm), the minimum distance between the tumor and major vessels to be preserved was 0 mm (0 to 4 mm), and the contact length of the tumor and major vessels was 26 mm (19 to 40 mm). Regarding the surgical outcome, the median operation time and blood loss were 559 minutes (508 to 919 min) and 620 mL (230 to 860 mL), respectively. We achieved a negative surgical margin (R0 resection) in all cases., Conclusions: Using ADPJ, we could perform R0 hepatectomy in all cases, which preoperatively were considered to have a high chance of being margin positive. We consider the best indication for using ADPJ is when the tumor and vessels to be preserved are attached or very close over a long distance.

Introduction: In closure of a stoma, the small working space and adhesions hinder a precise surgical procedure, compared with conventional approaches to digestive surgery. The aim of this prospective study was to introduce a new technique of laparoscopic stoma closure (LASC)., Materials and Surgical Techniques: After starting with three trocars, it is a priority to dissect around the arising ileum; a linear stapler is precisely inserted in both orifices of the loop stoma and applied two times, extracorporeally. Ultimately, both the oral and anal sides of the loop ileum are cut and closed using a linear cutter stapler in a delta-shaped manner just under the abdominal wall, intracorporeally. Eventually, the arising stoma is removed using an intra-abdominal and cutaneous approach., Discussion: LASC for patients with a temporary loop ileostomy is safe and feasible. More data and experience will be required to verify the benefits of this new technique., (© 2020 The Authors. Asian Journal of Endoscopic Surgery published by Asia Endosurgery Task Force and Japan Society of Endoscopic Surgery and John Wiley & Sons Australia, Ltd.)

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive types of cancer, and its prognosis is abysmal; only 25% of patients survive one year, and 5% live for five years. MicroRNA (miRNA) signature analysis of PDAC revealed that both strands of pre- miR-30c ( miR-30c-5p , guide strand; miR-30c-2-3p , passenger strand) were significantly downregulated, suggesting they function as tumor-suppressors in PDAC cells. Ectopic expression assays demonstrated that these miRNAs attenuated the aggressiveness of PDAC cells, e.g., cell proliferation, migration, and invasiveness. Through a combination of in silico analyses and gene expression data, we identified 216 genes as putative oncogenic targets of miR-30c-5p and miR-30c-2-3p regulation in PDAC cells. Among these, the expression of 18 genes significantly predicted the 5-year survival rates of PDAC patients ( p < 0.01). Importantly, the expression levels of 10 genes ( YWHAZ, F3, TMOD3, NFE2L3, ENDOD1, ITGA3, RRAS, PRSS23, TOP2A , and LRRFIP1 ) were found to be independent prognostic factors for patient survival ( p < 0.01). We focused on TOP2A (DNA Topoisomerase II Alpha) and investigated its potential as a therapeutic target for PDAC. The overexpression of TOP2A and its transcriptional activators ( SP1 and HMGB2 ) was detected in PDAC clinical specimens. Moreover, the knockdown of TOP2A enhanced the sensitivity of PDAC cells to anticancer drugs. Our analyses of the PDAC miRNA signature and tumor-suppressive miRNAs provide important insights into the molecular pathogenesis of PDAC.

Our recent studies have implicated some passenger strands of miRNAs in the molecular pathogenesis of human cancers. Analysis of the microRNA (miRNA) expression signature in pancreatic ductal adenocarcinoma (PDAC) has shown that levels of miR-30a-3p, the passenger strand derived from pre-mir-30a, are significantly downregulated in PDAC tissues. This study aimed to identify the oncogenes closely involved in PDAC molecular pathogenesis under the regulation of miR-30a-3p. Ectopic expression assays showed that miR-30a-3p expression inhibited the aggressiveness of the PDAC cells, suggesting that miR-30a-3p acts as a tumor-suppressive miRNA in PDAC cells. We further identified 102 putative targets of miR-30a-3p regulation in PDAC cells by combining in silico analysis with gene expression data. Of these, ten genes ( EPS8 , HMGA2 , ENDOD1 , SLC39A10 , TGM2 , MGLL , SERPINE1 , ITGA2 , DTL, and UACA ) were independent prognostic factors in multivariate analysis of survival of patients with PDAC ( p < 0.01). We also investigated the oncogenic function of the integrin ITGA2 in PDAC cell lines. The integrin family comprises cell adhesion molecules expressed as heterodimeric, transmembrane proteins on the surface of various cells. Overexpression of ITGA2/ITGB1 (an ITGA2 binding partner) was detected in the PDAC clinical specimens. The knockdown of ITGA2 expression attenuated the malignant phenotypes of the PDAC cells. Together, results from these microRNA-based approaches can accelerate our understanding of PDAC molecular pathogenesis.

RNA-sequencing-based microRNA (miRNA) expression signatures have revealed that miR-148a-5p (the passenger strand of the miR-148a-duplex) is downregulated in various kinds of cancer tissues. Analysis of The Cancer Genome Atlas (TCGA) database showed that low expression of miR-148a-5p was predictive of a lower survival rate (p = 0.041) in patients with gastric cancer (GC). Downregulation of miR-148a-5p was confirmed in GC clinical specimens, and its ectopic expression attenuated GC cell proliferation. Our search for miRNA target genes identified a total of 18 oncogenic targets of miR-148a-5p in GC cells. Among these targets, high expression levels of six genes (THBS2, P4HA3, SERPINH1, CDH11, BCAT1, and KCNG3) were closely associated with a poor prognosis (10-year survival rates) in GC patients (p < 0.05) according to TCGA database analyses. Furthermore, we focused on SERPINH1 as a chaperone protein involved in collagen folding in humans. Aberrant expression of SERPINH1 (mRNA and protein levels) was confirmed in GC clinical specimens. Knockdown assays of SERPINH1 using siRNAs resulted in inhibition of the aggressive phenotype of GC cells. Exploring the molecular networks controlled by miRNAs (including miRNA passenger strands) will broaden our understanding of the molecular pathogenesis of GC.

Aberrantly expressed microRNA (miRNA) are known to disrupt intracellular RNA networks in cancer cells. Exploring miRNA-dependent molecular networks is a major challenge in cancer research. In this study, we performed RNA-sequencing of breast cancer (BrCa) clinical specimens to identify tumor-suppressive miRNA in BrCa. In total, 64 miRNA were identified as candidate tumor-suppressive miRNA in BrCa cells. Analysis of our BrCa signature revealed that several miRNA duplexes (guide strand/passenger strand) derived from pre-miRNA were downregulated in BrCa tissues (e.g. miR-99a-5p/-3p, miR-101-5p/-3p, miR-126-5p/-3p, miR-143-5p/-3p, and miR-144-5p/-3p). Among these miRNA, we focused on miR-101-5p, the passenger strand of pre-miR-101, and investigated its tumor-suppressive roles and oncogenic targets in BrCa cells. Low expression of miR-101-5p predicted poor prognosis in patients with BrCa (overall survival rate: P = 0.0316). Ectopic expression of miR-101-5p attenuated aggressive phenotypes, e.g. proliferation, migration, and invasion, in BrCa cells. Finally, we identified seven putative oncogenic genes (i.e. High Mobility Group Box 3, Epithelial splicing regulatory protein 1, GINS complex subunit 1 (GINS1), Tumor Protein D52, Serine/Arginine-Rich Splicing Factor Kinase 1, Vang-like protein 1, and Mago Homolog B) regulated by miR-101-5p in BrCa cells. The expression of these target genes was associated with the molecular pathogenesis of BrCa. Furthermore, we explored the oncogenic roles of GINS1, whose function had not been previously elucidated, in BrCa cells. Aberrant expression of GINS1 mRNA and protein was observed in BrCa clinical specimens, and high GINS1 expression significantly predicted poor prognosis in patients with BrCa (overall survival rate: P = 0.0126). Knockdown of GINS1 inhibited the malignant features of BrCa cells. Thus, identification of tumor-suppressive miRNA and molecular networks controlled by these miRNA in BrCa cells may be an effective strategy for elucidation of the molecular pathogenesis of this disease., (© 2019 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.)

Background: /Objectives: The lung is a major metastatic site of pancreatic cancer (PC). We aimed to assess the features and prognosis of patients with PC according to the recurrence pattern and the effect of resection of recurrent lung lesion., Methods: We enrolled 168 PC patients who had undergone macroscopically curative resection. All resected lung tumors were evaluated immunohistochemically for expressions of thyroid transcription factor-1 (TTF-1) and napsin A., Results: The most common site of first recurrence was the liver and local site, followed by the lung, peritoneum, and lymph node. Lung recurrence was observed significantly later than was liver recurrence. The median survival time (MST) after recurrence in patients with first recurrence in the lung was significantly longer than MST in patients with first recurrence in the liver (15.2 months vs 5.2 months, p = 0.039). Seven patients with lung recurrence underwent resection of the recurrent lesion. Surgical resection of single metastasis limited to the lung showed favorable overall survival after recurrence (MST = 36.5 months). Patients with single metastasis limited to the lung showed significantly lower value of FDG-PET SUV max of the primary pancreatic tumor., Conclusions: Patients with first recurrence in the lung showed better prognosis than did patients with first recurrence in the liver. Single metastasis limited to the lung could benefit from surgical resection and was significantly associated with lower FDG-PET SUV max of the primary pancreatic tumor., (Copyright © 2019 IAP and EPC. Published by Elsevier B.V. All rights reserved.)

Our ongoing analyses identifying dysregulated microRNAs (miRNAs) and their controlled target RNAs have shed light on novel oncogenic pathways in pancreatic ductal adenocarcinoma (PDAC). The PDAC miRNA signature obtained by RNA sequencing showed that both strands of pre-miR-130b (miR-130b-5p, the passenger strand and miR-130b-3p, the guide strand) were significantly downregulated in cancer tissues. Our functional assays revealed that miR-130b-5p significantly blocked the malignant abilities of PDAC cell lines (PANC-1 and SW1990), e.g., cancer cell proliferation, migration, and invasion. A total of 103 genes were identified as possible oncogenic targets by miR-130b-5p regulation in PDAC cells based on genome-wide gene expression analysis and in silico database search. Among the possible targets, high expression of 9 genes (EPS8, ZWINT, SMC4, LDHA, GJB2, ZCCHC24, TOP2A, ANLN, and ADCY3) predicted a significantly poorer prognosis of PDAC patients (5-year overall survival, p < 0.001). Furthermore, we focused on EPS8 because its expression had the greatest impact on patient prognosis (overall survival, p < 0.0001). Overexpression of EPS8 was detected in PDAC clinical specimens. Knockdown assays with siEPS8 showed that its overexpression enhanced cancer cell proliferation, migration, and invasion. Analysis of downstream RNA networks regulated by EPS8 indicated that MET, HMGA2, FERMT1, RARRES3, PTK2, MAD2L1, and FLI1 were closely involved in PDAC pathogenesis. Genes regulated by antitumor miR-130b-5p were closely involved in PDAC molecular pathogenesis. Our approach, discovery of antitumor miRNAs and their target RNAs, will contribute to exploring the causes of this malignant disease.

Previously, we established a microRNA (miRNA) expression signature in pancreatic ductal adenocarcinoma (PDAC) tissues using RNA sequencing and found significantly reduced expression of miR-204-5p . Here, we aimed to investigate the functional significance of miR-204-5p and to identify miR-204-5p target genes involved in PDAC pathogenesis. Cancer cell migration and invasion were significantly inhibited by ectopic expression of miR-204-5p in PDAC cells. Comprehensive gene expression analyses and in silico database searches revealed 25 putative targets regulated by miR-204-5p in PDAC cells. Among these target genes, high expression levels of RACGAP1 , DHRS9 , AP1S3 , FOXC1 , PRP11 , RHBDL2 and MUC4 were significant predictors of a poor prognosis of patients with PDAC. In this study, we focused on RACGAP1 (Rac guanosine triphosphatase-activating protein 1) because its expression was most significantly predictive of PDAC pathogenesis (overall survival rate: p = 0.0000548; disease-free survival rate: p = 0.0014). Overexpression of RACGAP1 was detected in PDAC clinical specimens, and its expression enhanced the migration and invasion of PDAC cells. Moreover, downstream genes affected by RACGAP1 (e.g., MMP28 , CEP55 , CDK1 , ANLN and S100A14 ) are involved in PDAC pathogenesis. Our strategy to identify antitumor miRNAs and their target genes will help elucidate the molecular pathogenesis of PDAC.

Although miR‑145‑5p (the guide strand of the miR‑145 duplex) is established as a tumor suppressive microRNA (miRNA or miR), the functional significance of miR‑145‑3p (the passenger strand of the miR‑145 duplex) in cancer cells and its targets remains obscure. In our continuing analysis of esophageal squamous cell carcinoma (ESCC) pathogenesis, the aim of the present study was to identify important oncogenes and proteins that are controlled by miR‑145‑3p. Overexpression of miR‑145‑3p significantly reduced cancer cell proliferation, migration and invasive abilities, and further increased apoptotic abilities. In ESCC cells, 30 possible oncogenic targets were identified that might be regulated by miR‑145‑3p. Among these targets, dehydrogenase/reductase member 2 (DHRS2) and myosin IB (MYO1B) were focused on to investigate their functional roles in ESCC cells. DHRS2 and MYO1B were directly regulated by miR‑145‑3p in ESCC cells by dual luciferase reporter assays. Aberrantly expressed DHRS2 and MYOIB were detected in ESCC clinical specimens, and their overexpression enhanced cancer cell aggressiveness. Genes regulated by antitumor miR‑145‑3p were closely associated with the molecular pathogenesis of ESCC. The approach based on antitumor miRNAs may contribute to the understanding of ESCC molecular pathogenesis.

Triple-negative breast cancer (TNBC) is an aggressive type of cancer associated with a poor prognosis. Identification of novel therapeutic targets in TNBC is urgently needed. Here, we investigated the microRNA (miRNA) expression signature of TNBC using clinical specimens. In total, 104 miRNAs (56 upregulated and 48 downregulated) were significantly dysregulated in TNBC tissues; miR-204-5p showed the most dramatic downregulation. We then examined the antitumor roles of miR-204-5p in breast cancer (BC) cells. Notably, cancer cell migration and invasion were significantly reduced by ectopic expression of miR-204-5p in BC cells. Genome-wide gene expression analysis and in silico database search revealed that 32 genes were putative miR-204-5p targets. High expression of AP1S3, RACGAP1, ELOVL6, and LRRC59 was significantly associated with poor prognosis in patients with BC, and adaptor-related protein complex 1 sigma 3 subunit (AP1S3) was directly regulated by miR-204-5p, as demonstrated by luciferase reporter assays. AP1S3 overexpression was detected in TNBC clinical specimens and enhanced cancer cell aggressiveness. We further analyzed downstream RNA networks regulated by AP1S3 in BC cells. Overall, this miRNA signature is expected to be an effective tool for identification of miRNA-mediated molecular mechanisms of TNBC pathogenesis.

Objective: Our recent studies have revealed that both strands of pre-miRNAs, the guide strand and the passenger strand, are involved in cancer pathogenesis. Analyses of miRNA expression signatures by RNA sequencing in head and neck squamous cell carcinoma (HNSCC) showed that both of the strands of pre-miR-150 (miR-150-5p and miR-150-3p) were significantly downregulated, and that these miRNAs acted as antitumor miRNAs in HNSCC cells. The aim of this study was to identify oncogenic genes in HNSCC cells that were regulated by miR-150-5p and miR-150-3p., Methods: Genome-wide gene expression studies, in silico analyses and dual-luciferase reporter assays were carried out to predict miR-150-5p and miR-150-3p regulation in HNSCC cells. Knockdown assay was applied to investigate the functional significance of the target gene. Overall patient survival as a function of target gene expression was estimated by The Cancer Genome Atlas (TCGA) database., Results: A total of 19 genes were putative targets of both miR-150-5p and miR-150-3p regulation. Among them, SPOCK1 (SPARC/osteonectin, cwcv and kazal-like domains proteoglycan 1) was directly regulated by both miRNAs in HNSCC cells. Knockdown studies using si-SPOCK1 showed that expression of SPOCK1 enhanced HNSCC cell aggressiveness. Overexpression of SPOCK1/SPOCK1 was confirmed in HNSCC clinical specimens. Interestingly, analysis of a large number of patients in the TCGA database (n=248) demonstrated that patients with high SPOCK1 expression had significantly shorter survival than did those with low SPOCK1 expression (P=0.0003). Moreover, 15 pathways were identified as SPOCK1-mediated downstream pathways., Conclusion: Downregulation of both strands of pre-miR-150 (miR-150-5p and miR-150-3p) and overexpression of SPOCK1 contribute to the aggressive nature of HNSCC. The involvement of passenger strand miRNA in the regulation of HNSCC pathogenesis is a novel concept in RNA research., (Copyright © 2017 Elsevier B.V. All rights reserved.)

MicroRNAs (miRNAs) are unique in that a single miRNA molecule regulates a vast number of RNA transcripts. Thus, aberrantly expressed miRNAs disrupt tightly controlled RNA networks in cancer cells. Our functional screening showed that expression of miR-124-3p was downregulated in pancreatic ductal adenocarcinoma (PDAC) tissues. Here, we aimed to investigate the anti-tumor roles of miR-124-3p in PDAC cells and to identify miR-124-3p -mediated oncogenic signaling in this disease. Ectopic expression of miR-124-3p inhibited cancer cell migration and invasion in PDAC cells. Moreover, restoration of miR-124-3p suppressed oncogenic signaling, as demonstrated by reduced phosphorylation of focal adhesion kinase, AKT, and extracellular signal-regulated kinase, in PDAC cells. Our in silico database analyses and luciferase reporter assays showed that two cell-surface matrix receptors, integrin α3 ( ITGA3 ) and integrin β1 ( ITGB1 ), were directly regulated by miR-124-3p in PDAC cells. Overexpression of ITGA3 and ITGB1 was confirmed in PDAC clinical specimens. Interestingly, a large number of cohort analyses from TCGA database showed that high expressions of ITGA3 and ITGB1 were significantly associated with poor prognosis of patients with PDAC. Knockdown of ITGA3 and ITGB1 by siRNAs markedly suppressed the migration and invasion abilities of PDAC cells. Moreover, downstream oncogenic signaling was inhibited by ectopic expression of miR-124-3p or knockdown of the two integrins. The discovery of anti-tumor miRNAs and miRNA-mediated oncogenic signaling may provide novel therapeutic targets for the treatment of PDAC., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.

We previously used RNA sequencing to establish the microRNA (miRNA) expression signature of pancreatic ductal adenocarcinoma (PDAC). We found that both strands of pre-miR-148a (miR-148a-5p: the passenger strand and miR-148a-3p: the guide strand) were downregulated in cancer tissues. Ectopic expression of miR-148a-5p and miR-148a-3p significantly inhibited cancer cell migration and invasion, indicating that both strands of pre-miR-148a had tumor-suppressive roles in PDAC cells. In silico database and genome-wide gene expression analyses identified a total of 15 genes that were putative targets regulated by these miRNAs. High expression of miR-148a-5p targets (PHLDA2, LPCAT2 and AP1S3) and miR-148a-3p targets (SMA, ENDOD1 and UHMK1) was associated with poor prognosis of patients with PDAC. Moreover, knockdown of PHLDA2 expression inhibited cancer cell aggressiveness, suggesting PHLDA2 acted as an oncogene in PDAC cells. Involvement of the passenger strand of pre-miR-148a (miR-148-5p) is a new concept in cancer research. Novel approaches that identify tumor-suppressive miRNA regulatory networks in lethal PDAC might provide new prognostic markers and therapeutic targets for this disease., (© 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Analyses of microRNA (miRNA) expression signatures obtained by RNA sequencing revealed that some passenger miRNAs (miR-144-5p, miR-145-3p, miR-149-3p, miR-150-3p, and miR-199a-3p) acted as anti-tumor miRNAs in several types of cancer cells. The involvement of passenger strands in the pathogenesis of human cancer is a novel concept. Based on the miRNA signature of bladder cancer (BC) obtained by RNA sequencing, we focused on both strands of the miR-223-duplex (miR-223-5p and miR-223-3p) and investigated their functional significance in BC cells. Ectopic expression of these miRNAs showed that both miR-223-3p (the guide strand) and miR-223-5p (the passenger strand) inhibited cancer cell migration and invasion of BC cells. The role of miR-223-5p (the passenger strand) has not been well studied. Combining gene expression studies and in silico database analyses, we demonstrated the presence of 20 putative target genes that could be regulated by miR-223-5p in BC cells. Among these targets, high expression of five genes (ANLN, INHBA, OIP5, CCNB1, and CDCA2) was significantly associated with poor prognosis of BC patients based on The Cancer Genome Atlas (TCGA) database. Moreover, we showed that a gene (ANLN) encoding a multifunctional actin-binding protein was directly regulated by miR-223-5p in BC cells. Overexpression of ANLN was observed in BC clinical specimens and high expression of ANLN was significantly associated with poor prognosis of BC patients. We suggest that studies of regulatory cancer networks, including the passenger strands of miRNAs, may provide new insights into the pathogenic mechanisms of BC.

Analysis of the microRNA (miRNA) expression signature of head and neck squamous cell carcinoma (HNSCC) based on RNA sequencing showed that dual strands of pre‑miR‑145 (miR‑145‑5p, guide strand; and miR‑145‑3p, passenger strand) were significantly reduced in cancer tissues. In miRNA biogenesis, passenger strands of miRNAs are degraded and have no biological activities in cells. The aims of this study were to investigate the functional significance of the passenger strand of miR‑145 and to identify miR‑145‑3p‑regulated oncogenic genes in HNSCC cells. Expression levels of miR‑145‑5p and miR‑145‑3p were significantly downregulated in HNSCC tissues and cell lines (SAS and HSC3 cells). Ectopic expression of miR‑145‑3p inhibited cancer cell proliferation, migration and invasion, similar to miR‑145‑5p, in HNSCC cells. Myosin 1B (MYO1B) was directly regulated by miR‑145‑3p, and knockdown of MYO1B by siRNA inhibited cancer cell aggressiveness. Overexpression of MYO1B was confirmed in HNSCC clinical specimens by analysis of protein and mRNA levels. Interestingly, high expression of MYO1B was associated with poor prognosis in patients with HNSCC by analysis of The Cancer Genome Atlas database (p=0.00452). Our data demonstrated that the passenger strand of miR‑145 acted as an antitumor miRNA through targeting MYO1B in HNSCC cells. The involvement of dual strands of pre‑miR‑145 (miR‑145‑5p and miR‑145‑3p) in the regulation of HNSCC pathogenesis is a novel concept in present RNA research.

Analysis of our microRNA (miRNA) expression signatures of human cancers based on RNA sequencing have shown that both strands of pre-miR-150, miR-150-5p (the guide strand) and miR-150-3p (the passenger strand), are significantly reduced in cancer tissues. We have investigated the functional significance of both strands of pre-miR-150 in cancer cells. The aim of this study was to investigate the antitumor function of these miRNAs and how these miRNAs regulated oncogenic targets in esophageal squamous cell carcinoma (ESCC). Ectopic expression studies demonstrated that both strands of pre-miR-150 miRNA inhibited ESCC cancer cell migration and invasion, indicating that both miR-150-5p and miR-150-3p acted as antitumor miRNAs. A combination of genome-wide gene expression analyses and in silico database searches showed that SPOCK1 (SPARC/osteonectin, cwcv and kazal-like domains proteoglycan 1) was a candidate target of miR-150-5p and miR-150-3p in ESCC cells. Luciferase reporter assays showed that SPOCK1 was directly regulated by these miRNAs. Silencing of SPOCK1 by small interfering RNA inhibited cancer cell migration and invasion. Overexpression of SPOCK1/SPOCK1 was confirmed by real-time PCR methods and immunohistochemistry. Taken together, downregulation of both strands of pre-miR-150 and overexpression of SPOCK1 are involved in ESCC pathogenesis. The involvement of passenger strand miRNAs in the regulation of cancer cell aggressiveness is a novel concept in RNA research.

Analysis of our original microRNA (miRNA) expression signature of patients with advanced renal cell carcinoma (RCC) showed that microRNA-10a-5p (miR-10a-5p) was significantly downregulated in RCC specimens. The aims of the present study were to investigate the antitumor roles of miR-10a-5p and the novel cancer networks regulated by this miRNA in RCC cells. Downregulation of miR-10a-5p was confirmed in RCC tissues and RCC tissues from patients treated with tyrosine kinase inhibitors (TKI). Ectopic expression of miR-10a-5p in RCC cell lines (786-O and A498 cells) inhibited cancer cell migration and invasion. Spindle and kinetochore-associated protein 1 (SKA1) was identified as an antitumor miR-10a-5p target by genome-based approaches, and direct regulation was validated by luciferase reporter assays. Knockdown of SKA1 inhibited cancer cell migration and invasion in RCC cells. Overexpression of SKA1 was observed in RCC tissues and TKI-treated RCC tissues. Moreover, analysis of The Cancer Genome Atlas database demonstrated that low expression of miR-10a-5p and high expression of SKA1 were significantly associated with overall survival in patients with RCC. These findings showed that downregulation of miR-10a-5p and overexpression of the SKA1 axis were highly involved in RCC pathogenesis and resistance to TKI treatment in RCC., (© 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

We analysed the RNA sequence-based microRNA (miRNA) signature of pancreatic ductal adenocarcinoma (PDAC). Aberrantly expressed miRNAs were successfully identified in this signature. Using the PDAC signature, we focused on 4 clustered miRNAs, miR-216a-5p , miR-216a-3p , miR-216b-5p and miR-216b-3p on human chromosome 2p16.1. All members of the miR-216 cluster were significantly reduced in PDAC specimens. Ectopic expression of these miRNAs suppressed cancer cell aggressiveness, suggesting miR-216 cluster as anti-tumour miRNAs in PDAC cells. The impact of miR-216b-3p (passenger strand of pre- miR-216b ) on cancer cells is still ambiguous. Forkhead box Q1 ( FOXQ1 ) was directly regulated by miR-216b-3p and overexpression of FOXQ1 was confirmed in clinical specimens. High expression of FOXQ1 predicted a shorter survival of patients with PDAC by Kaplan-Meier analysis. Loss-of-function assays showed that cancer cell migration and invasion activities were significantly reduced by si FOXQ1 transfectants. We investigated pathways downstream from FOXQ1 by using genome-wide gene expression analysis. Identification of the miR-216-3p/FOXQ1 -mediated network in PDAC should enhance understanding of PDAC aggressiveness at the molecular level., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.

Analysis of our microRNA (miRNA) expression signature in human cancers has shown that guide and passenger strands of pre-miR‑150, i.e., miR‑150‑5p and miR‑150‑3p, are significantly downregulated in cancer tissues. In miRNA biogenesis, the passenger strand of miRNA is degraded and is thought to have no functions. Thus, the aim of this study was to investigate the functional significance of miR‑150‑5p and miR‑150‑3p in naïve prostate cancer (PCa) and castration-resistant prostate cancer (CRPC). Ectopic expression assays showed that both strands of miRNAs significantly suppressed cancer cell migration and invasion. Our strategies of miRNA target searching demonstrated that SPOCK1 (SPARC/osteonectin, cwcv and kazal like domains proteoglycan 1) was directly regulated by miR‑150‑5p and miR‑150‑3p. Knockdown of SPOCK1 by siRNA inhibited cancer cell aggressiveness. Moreover, overexpression of SPOCK1 was observed in naïve PCa and CRPC tissues. Taken together, dual strands of pre-miR‑150 (miR‑150‑5p and miR‑150‑3p) acted as antitumor miRNAs in naïve PCa and CRPC cells. Expression of oncogenic SPOCK1 was involved in naïve PCa and CRPC pathogenesis. Novel approaches to analysis of antitumor miRNA-regulated RNA networks in cancer cells may provide new insights into the pathogenic mechanisms of naïve PCa and CRPC.

Analysis of our microRNA (miRNA) expression signature of pancreatic ductal adenocarcinoma (PDAC) revealed that microRNA-217 ( miR-217 ) was significantly reduced in cancer tissues. The aim of this study was to investigate the antitumor roles of miR-217 in PDAC cells and to identify miR-217 -mediated molecular pathways involved in PDAC aggressiveness. The expression levels of miR-217 were significantly reduced in PDAC clinical specimens. Ectopic expression of miR-217 significantly suppressed cancer cell migration and invasion. Transcription of actin-binding protein Anillin (coded by ANLN ) was detected by our in silico and gene expression analyses. Moreover, luciferase reporter assays showed that ANLN was a direct target of miR-217 in PDAC cells. Overexpression of ANLN was detected in PDAC clinical specimens by real-time PCR methods and immunohistochemistry. Interestingly, Kaplan-Meier survival curves showed that high expression of ANLN predicted shorter survival in patients with PDAC by TCGA database analysis. Silencing ANLN expression markedly inhibited cancer cell migration and invasion capabilities of PDAC cell lines. We further investigated ANLN -mediated downstream pathways in PDAC cells. "Focal adhesion" and "Regulation of actin binding protein" were identified as ANLN -modulated downstream pathways in PDAC cells. Identification of antitumor miR-217 / ANLN -mediated PDAC pathways will provide new insights into the potential mechanisms underlying the aggressive course of PDAC., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.