The rice wound-inducible transcription factor RERJ1 sharing same signal transduction pathway with OsMYC2 is necessary for defense response to herbivory and bacterial blight.

KEY MESSAGE: This study describes biological functions of the bHLH transcription factor RERJ1 involved in the jasmonate response and the related defense-associated metabolic pathways in rice, with particular focus on deciphering the regulatory mechanisms underlying stress-induced volatile emission and herbivory resistance. RERJ1 is rapidly and drastically induced by wounding and jasmonate treatment but its biological function remains unknown as yet. Here we provide evidence of the biological function of RERJ1 in plant defense, specifically in response to herbivory and pathogen attack, and offer insights into the RERJ1-mediated regulation of metabolic pathways of specialized defense compounds, such as monoterpene linalool, in possible collaboration with OsMYC2-a well-known master regulator in jasmonate signaling. In rice (Oryza sativa L.), the basic helix-loop-helix (bHLH) family transcription factor RERJ1 is induced under environmental stresses, such as wounding and drought, which are closely linked to jasmonate (JA) accumulation. Here, we investigated the biological function of RERJ1 in response to biotic stresses, such as herbivory and pathogen infection, using an RERJ1-defective mutant. Transcriptome analysis of the rerj1-Tos17 mutant revealed that RERJ1 regulated the expression of a typical family of conserved JA-responsive genes (e.g., terpene synthases, proteinase inhibitors, and jasmonate ZIM domain proteins). Upon exposure to armyworm attack, the rerj1-Tos17 mutant exhibited more severe damage than the wildtype, and significant weight gain of the larvae fed on the mutant was observed. Upon Xanthomonas oryzae infection, the rerj1-Tos17 mutant developed more severe symptoms than the wildtype. Among RERJ1-regulated terpene synthases, linalool synthase expression was markedly disrupted and linalool emission after wounding was significantly decreased in the rerj1-Tos17 mutant. RERJ1 appears to interact with OsMYC2-a master regulator of JA signaling-and many OsJAZ proteins, although no obvious epistatic interaction was detected between them at the transcriptional level. These results indicate that RERJ1 is involved in the transcriptional induction of JA-mediated stress-responsive genes via physical association with OsMYC2 and mediates defense against herbivory and bacterial infection through JA signaling.

The blockade of interleukin-33 released by hepatectomy would be a promising treatment option for cholangiocarcinoma.

Interleukin-33 (IL-33), an alarmin released during tissue injury, facilitates the development of cholangiocarcinoma (CCA) in a murine model. However, it is unclear whether IL-33 is associated with human CCA. The aim of this study was to support the following hypothesis: IL-33 is released during hepatectomy for CCA, subsequently facilitating the development of subclinical CCA and eventually leading to recurrent disease. IL-33 expression was assessed in various samples from both humans and mice including resected liver and paired plasma samples collected at hepatectomy and after surgery, and its influences on recurrent disease and patient prognosis were determined. Homogenized human liver samples with high or low IL-33 expression were added to the culture medium of human CCA cells, and the changes in proliferation and migration were evaluated. To examine the effects of inhibiting the IL-33 release induced by hepatectomy, syngraft transplantation of murine CCA cells was performed in C57BL/6J mice with or without IL-33 blockade. The amount of IL-33 released into the plasma during hepatectomy correlated with the background liver expression. High expression of IL-33 in the liver was an independent risk factor for recurrence. Homogenized liver tissue strongly expressing IL-33 increased both the proliferation and migration of tumor cells. Mice who underwent hepatectomy exhibited CCA progression in the remnant liver, whereas blockade of IL-33 during hepatectomy inhibited tumor progression. Thus, we concluded that surgery for CCA with curative intent paradoxically induced IL-33 release, which facilitated CCA recurrence, and anti-IL-33 therapy during hepatectomy might reduce the risk of CCA recurrence.

Impact of an older donor pancreas on the outcome of pancreas transplantation: single-center experience of the expansion of donor criteria.

PURPOSE: The impact of using an older donor pancreas on the clinical outcomes of pancreas transplantation (PTx) is unknown. We investigated this by comparing the outcomes of PTx using older and younger donors in a single Japanese center, to expand the donor criteria. METHODS: The subjects were 54 patients who received PTx from deceased donors in our institution. Posttransplant outcomes were analyzed based on donor age, with older donors defined as those aged ≥ 60 years. RESULTS: The donors included six older (11.1%; aged 64 ± 4 years) and 48 younger donors (88.9%; aged 43 ± 12 years). There was no significant difference in the donor age between the recipients with vs. those without postoperative complications or between those with vs. those without early pancreas graft loss. Long-term outcomes, including overall, pancreas graft, and kidney graft survival after PTx, did not differ significantly between the older and younger donor groups. Graft age, defined as the age of the donor at the time of procurement plus the graft survival period, was not associated with graft loss. CONCLUSION: Our results suggest that post-transplant outcomes of PTx using pancreas from older donors aged ≥ 60 years are comparable to those using pancreas from younger donors, and support expansion of the donor pool for transplantation therapy for type 1 diabetes mellitus.

A Prospective, Multi-Center Phase I Study of Postoperative Enoxaparin Treatment in Patients Undergoing Curative Hepatobiliary-Pancreatic Surgery for Malignancies.

BACKGROUND: Venous thromboembolism (VTE) is one of the critical complications that can occur after surgery. A positive association between cancer and VTE risk is well established; however, the safety and efficacy of VTE prophylaxis have not been established in hepatobiliary-pancreatic surgery, especially in surgery for malignancies. METHODS: A prospective, multi-center Phase I study to determine the safety of enoxaparin was performed. Subcutaneous injection of enoxaparin was initiated 48-72 h after surgery and repeated for 8 days. The primary endpoint was the incidence of bleeding events. This study was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000007761). RESULTS: A total of 154 patients was registered and 133 patients including 74 hepatectomies and 35 pancreaticoduodenectomies were analyzed. Three patients (2.3%) exhibited major bleeding events postoperatively, while 7 (5.2%) had minor bleeding. No Symptomatic VTE was observed. CONCLUSIONS: Our study indicated that enoxaparin was well tolerated and safe for patients who received hepatobiliary-pancreatic surgery for malignancies.

Exosomal miR-155 Derived from Hepatocellular Carcinoma Cells Under Hypoxia Promotes Angiogenesis in Endothelial Cells.

PURPOSE: In this study, we aim to clarify whether exosomes secreted from hepatocellular carcinoma (HCC) cells under hypoxia affect angiogenesis in endothelial cells. METHODS: Exosomes derived from human liver cancer cell lines were cultured under hypoxic or normoxic conditions for 24 h, isolated using ExoQuick-TC®, and co-cultured with HUVECs to evaluate angiogenic activity. We also evaluated the expression of miR-155 in the exosomes from 40 patients with HCC. RESULTS: Exosomes under hypoxia remarkably enhanced tube formation of HUVECs. Both cellular and exosomal miR-155 were significantly up-regulated under hypoxic conditions. Knockdown of miR-155 in HCC cells attenuated the promotion of tube formation by exosomes under hypoxia in HUVECs, and high expression of exosomal miR-155 in preoperative plasma was significantly correlated with early recurrence. CONCLUSION: These results suggest that exosomes derived from HCC cells under hypoxia induce tube formation of HUVECs and that exosomal miR-155 may affect angiogenic activity in HCC.

Role of histone deacetylase 1 in distant metastasis of pancreatic ductal cancer.

Current therapies for pancreatic ductal cancer (PDAC) do not sufficiently control distant metastasis. Thus, new therapeutic targets are urgently needed. Numerous studies have suggested that the epithelial-mesenchymal transition (EMT) is pivotal for metastasis of carcinomas. The fact that the EMT is reversible suggests the possibility that it is induced by an epigenetic mechanism. In this study, we aimed to investigate the role of histone deacetylase 1 (HDAC1), which is an epigenetic mechanism on distant metastasis of PDAC. We investigated the HDAC1 expression in 103 resected PDAC specimens obtained from patients who were treated with/without preoperative therapy using immunohistochemistry. To validate the findings in the clinical samples, we evaluated the HDAC1 activity, the EMT-associated genes and the migration/invasion ability in vitro, and performed an HDAC1 inhibitor assay. The high expression of HDAC1 in clinical samples was significantly associated with poor progression-free survival, especially distant metastasis-free survival. In vitro, HDAC1 inhibitors decreased the invasion ability and reversed the EMT change; the only factor to show a concomitant decrease was the expression of SNAIL. We confirmed that the HDAC1 expression was associated with the SNAIL expression in clinical samples. Moreover, the resistant cells and parental cells did not show any significant differences in the expression of HDAC1; this was consistent with the finding that preoperative therapy did not alter the HDAC1 expression in clinical samples. The targeting of HDAC1, which could suppress metastasis by inhibiting the EMT, is a promising treatment option for PDAC.

Possible involvement of Enterococcus infection in the pathogenesis of chronic pancreatitis and cancer.

(Aim) Bacterial infection underlies the pathogenesis of many human diseases, including acute and chronic inflammation. Here, we investigated a possible role for bacterial infection in the progression of chronic pancreatitis. (Materials and Methods) Pancreatic juice was obtained from patients with pancreatic cancer (n = 20) or duodenal cancer/bile duct cancer (n = 16) and subjected to PCR using universal primers for the bacterial 16S ribosomal RNA gene. Bacterial species were identified by PCR using bile samples from four pancreatic cancer patients. PCR products were subcloned into T-vectors, and the sequences were then analyzed. Immunohistochemical and serologic analyses for Enterococcus faecalis infection were performed on a large cohort of healthy volunteers and patients with chronic pancreatitis or pancreatic cancer and on mice with caerulein-induced chronic pancreatitis. The effect of E. faecalis antigens on cytokine secretion by pancreatic cancer cells was also investigated. (Results) We found that 29 of 36 pancreatic juice samples were positive for bacterial DNA. Enterococcus and Enterobacter species were detected primarily in bile, which is thought to be a pathway for bacterial infection of the pancreas. Enterococcus faecalis was also detected in pancreatic tissue from chronic pancreatitis and pancreatic cancer patients; antibodies to E. faecalis capsular polysaccharide were elevated in serum from chronic pancreatitis patients. Enterococcus-specific antibodies and pancreatic tissue-associated E. faecalis were detected in mice with caerulein-induced chronic pancreatitis. Addition of Enterococcus lipoteichoic acid and heat-killed bacteria induced expression of pro-fibrotic cytokines by pancreatic cancer cells in vitro. (Conclusion) Infection with E. faecalis may be involved in chronic pancreatitis progression, ultimately leading to development of pancreatic cancer.

Vitamin D Supplementation is a Promising Therapy for Pancreatic Ductal Adenocarcinoma in Conjunction with Current Chemoradiation Therapy.

BACKGROUND: The cancer-associated fibroblasts (CAFs) in pancreatic ductal adenocarcinoma (PDAC) are well known to play a dominant role in distant metastasis. Nevertheless, the effect on CAFs with current chemoradiation therapies remains uncertain. OBJECTIVE: This study aimed to reveal the role of CAFs under current chemoradiation therapy (CRT) and investigate the factors regulating CAFs. METHODS: α-SMA-positive cells in 86 resected PDAC specimens with/without preoperative CRT were evaluated by immunohistochemistry. Various factors, including the plasma levels of vitamin D, were investigated for association with the number of CAFs or distant metastasis-free survival (DMFS). Human pancreatic satellite cells (hPSCs) extracted from clinical specimens were used to validate the factors. RESULTS: All PDAC samples contained CAFs but the number varied widely. Multivariate analysis for DMFS indicated a larger number of CAFs was a significant risk factor. Univariate analysis for the number of CAFs identified two clinical factors: preoperative CRT and lower plasma levels of vitamin D. In subgroup analysis, the higher plasma level of vitamin D was a dominant factor for longer DMFS in PDAC patients after preoperative CRT. These results were validated by using extracted hPSCs. Irradiation activated stromal cells into CAFs facilitating malignant characteristics of PDAC and the change was inhibited by vitamin D supplementation in vitro. CONCLUSION: In conjunction with established current therapies, vitamin D supplementation may be an effective treatment for PDAC patients by inactivating CAFs.

Hypoxia-Induced PLOD2 is a Key Regulator in Epithelial-Mesenchymal Transition and Chemoresistance in Biliary Tract Cancer.

BACKGROUND: The prognosis of biliary tract cancer (BTC) is unfavorable due to its chemoresistance. Hypoxia triggers epithelial-to-mesenchymal transition (EMT), which is closely related to drug resistance. In this study, we focused on the functional roles of procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a hypoxia-induced gene, in BTC, and assessed the clinical significance of PLOD2. METHODS: The expression of PLOD2 under hypoxia was assessed in BTC cell lines. Gemcitabine-resistant (GR) BTC cell lines were transfected with small interfering RNA (siRNA) against PLOD2, and EMT markers and chemoresistance were evaluated. PLOD2 expression was also characterized using immunohistochemistry in BTC clinical specimens following resection. Patient survival was analyzed and the role of PLOD2 expression was examined. RESULTS: The expression of PLOD2 was induced by hypoxia in vitro and was upregulated in BTC-GR cell lines, which had low expression of epithelial markers and high expression of mesenchymal markers. Downregulation of PLOD2 by siRNA resulted in improved chemoresistance, recovery of epithelial markers, and reduction of mesenchymal markers. In the resected BTC samples, PLOD2 expression was significantly correlated with lymph node metastasis (p = 0.037) and stage (p = 0.001). Recurrence-free survival (p = 0.011) and overall survival (p < 0.001) rates were significantly lower in patients with high expression of PLOD2. PLOD2 expression was an independent prognostic factor for overall survival (p = 0.019). CONCLUSIONS: The expression of PLOD2 influenced chemoresistance through EMT, and high expression of PLOD2 was a significant unfavorable prognostic factor in BTC patients. PLOD2 might be a potential therapeutic target for overcoming chemoresistance.

Plasma ghrelin suppression as an early predictor for postoperative complications after pancreatoduodenectomy.

BACKGROUND/OBJECTIVES: The gut peptide hormone ghrelin induces appetite and exhibits an anti-inflammatory effect. Serial perioperative changes in ghrelin have been examined in several surgical procedures, but few in pancreatectomy. The present study analyzed perioperative changes in plasma ghrelin levels after pancreaduodenectomy (PD). METHODS: The study included 24 patients undergoing PD between May 2015 and January 2016 at Osaka University Hospital. Plasma ghrelin and interleukin-6 (IL-6) levels, as well as white blood cells (WBCs) and C-reactive protein (CRP), were measured preoperatively and on postoperative day (POD) 1, 3, 7, and 14 by enzyme-linked immunosorbent assay. The relationship between the individual ghrelin ratio relative to preoperative value (IGR) and the development of grade IIIa-V Clavien-Dindo (CD) complications was examined. RESULTS: Twelve patients (50%) developed grade IIIa CD complications (n = 6 [25%] pancreatic fistula, n = 7 [29%] intraabdominal abscess, n = 3 [13%] post-pancreatectomy hemorrhage, n = 5 [21%] wound infection, and n = 1 [4%] lymphorrhea). The IGR on POD 1 was significantly lower (p = 0.014) in patients who developed the complications compared to those who did not, but no significant differences were found in terms of WBC, CRP, or IL-6 on POD 1. When the IGR cut-off was set to 82% by receiver operative curve analysis, the sensitivity was 83%, specificity 75% and area under the curve 0.80. The lower IGR group (≤82%) had more postoperative complications and longer hospital stay. CONCLUSIONS: The IGR on POD 1 after PD is a useful marker for predicting postoperative complications.

Minimally invasive liver resection for hepatocellular carcinoma of patients with liver damage B: A propensity score-based analysis.

AIM: Minimally invasive liver resection (MILR) is considered a safe and feasible treatment for malignant liver tumors. However, few studies have investigated the surgical outcomes of MILR in patients with impaired liver function. Liver damage is used for consideration of hepatectomy. The aim of this study is to clarify the efficacy of MILR for patients with impaired liver function by using propensity score matching. METHODS: Ninety-nine patients with liver damage B underwent hepatic resection were analyzed. The patients were divided into two groups, the MILR group (n = 24) and the open liver resection (OLR) group (n = 75). After matching of a propensity score, we compared clinicopathological features and surgical outcomes. RESULTS: After matching, 36 patients (18 patients from each group) were selected and the patients' characteristics and tumor characteristics were not significantly different between the two groups. Blood loss (P = 0.0163) and complication rate (P = 0.0162) were significantly decreased in the MILR group. Complications were observed in eight patients, comprising one patient in the MILR group and seven patients in the OLR group. The postoperative hospital stay was significantly shortened in the MILR group (P = 0.0118). CONCLUSION: Minimally invasive liver resection might be effective for patients with impaired liver function. It reduces surgical complications and consequently shortens hospitalization time.

Clinical significance of CD13 and epithelial mesenchymal transition (EMT) markers in hepatocellular carcinoma.

BACKGROUND & AIMS: To improve prognosis in patients with hepatocellular carcinoma (HCC), the molecular mechanisms of tumor thrombus formation and metastasis must be clarified. The epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) play crucial roles in tumor invasion and metastasis. This study aimed to reveal the clinical significance of the expression of the functional CSC marker, CD13, and investigate the correlation between CD13 expression and two EMT markers, E-cadherin and vimentin. METHODS: We acquired clinical samples from 86 patients with HCC that underwent radical liver resections. We performed immunohistochemistry to evaluate CD13, E-cadherin and vimentin expression. We investigated the relationships among protein expression levels, clinicopathological factors and prognosis. RESULTS: Based on CD13 expression, patients were categorized into CD13high (n = 30, 34.9%) and CD13low (n = 56, 65.1%) groups. The mean tumor size was significantly larger in the CD13high group than in the CD13low group (P = 0.049). Compared with the CD13low group, the CD13high group showed significantly earlier recurrences and shorter survival times. In the multivariate analysis, CD13high was an independent prognostic factor for overall survival (hazard ratio, 1.98; P = 0.044). The disease-free survival time was shorter in the vimentin-positive group than that in the vimentin-negative group (P = 0.014). In an analysis of the relationship between CD13 and EMT, there was no significant correlation between CD13 and EMT markers. CONCLUSIONS: Our findings suggested that CD13 enrichment was correlated with early recurrences, and poor prognosis in patients with HCC and that vimentin was associated with early recurrences. CD13 represents a potential therapeutic target for HCC, because CSC regulation and EMT suppression are essential in cancer therapy.

Short-term surgical outcomes of minimally invasive repeat hepatectomy for recurrent liver cancer.

BACKGROUND: Repeat liver resection is an effective treatment, with long-term surgical outcomes for recurrent hepatocellular carcinoma and colorectal liver metastasis. However, the efficacy of a minimally invasive surgical approach for recurrent liver cancer is not yet confirmed. The purpose of this study is to examine the efficacy of minimally invasive repeat liver resection (MISRLR) compared with open repeat liver resection (ORLR) for primary and metastatic liver cancer. Here, we retrospectively analyzed the clinicopathological features and short-term surgical outcomes of patients undergoing MISRLR and ORLR. METHODS: From 2005 to 2016, 97 patients with liver cancer underwent repeat hepatectomy. Of these patients, 68 patients receiving macroscopically curative resection and only hepatectomy, without other additional operations, were selected. Twenty patients underwent MISRLR and 48 patients underwent ORLR. We compared the clinicopathological and surgical parameters in the MISRLR group with those in the ORLR group. RESULTS: There were no statistically significant differences in patients' gender, age, viral infection status, Child-Pugh classification, tumor size, tumor number, tumor location, or the presence of liver cirrhosis in the two groups. The operative times were similar, but blood loss was significantly lower in MISRLR group (159 vs. 502 ml, P = 0.0035). The length of the postoperative hospital stay was significantly shorter in the MISRLR group (14.2 vs. 19.2 days, P = 0.0275). Postoperative complications were observed only in the ORLR group, with a complication rate of 19%. CONCLUSIONS: We demonstrate that MISRLR for primary and metastatic liver cancer reduces blood loss and postoperative complications compared with ORLR. MISRLR might be a feasible and effective procedure for the selected patients.

Clinical Impact of Preoperative Sarcopenia on the Postoperative Outcomes After Pancreas Transplantation.

BACKGROUND: The importance of evaluating sarcopenia is increasingly being recognized in the field of transplantation because sarcopenia can have an adverse effect on the treatment outcomes. However, the clinical significance of preoperative sarcopenia on the postoperative outcomes following pancreas transplantation (PTx) has been largely unknown. The objective of this study was to investigate the role of preoperative sarcopenia in predicting the postoperative outcomes following PTx in recipients with type 1 diabetes mellitus (T1D). METHODS: Forty-one recipients with severe T1D who underwent PTx were retrospectively reviewed. The psoas muscle mass index (PMI) and intramuscular adipose tissue content (IMAC), as determined by preoperative computed tomography, were substituted for the quantity and quality of skeletal muscle for the definition of sarcopenia, respectively. Gender-specific quartiles were generated, and PMI lower than the first quantile or IMAC higher than the third quantile was considered to represent sarcopenia. The postoperative outcomes included postoperative surgical complications and pancreas graft survival. RESULTS: Sarcopenia was identified in 11 recipients according to both the PMI and IMAC stratifications. The multivariate analyses revealed that high IMAC was independently associated with the development of postoperative surgical complications (odds ratio, 9.35; p = 0.016). In addition, the recipients with high IMAC showed unfavorable graft survival compared to those with normal IMAC (log-rank test; p = 0.038). In contrast, low PMI was not significantly associated with the postoperative outcomes. CONCLUSIONS: Our data suggested that preoperative sarcopenia, especially a decline in the quality of skeletal muscle, predicted poorer postoperative outcomes in T1D recipients undergoing PTx.

Prolonged Neoadjuvant Therapy for Locally Advanced Pancreatic Cancer.

PURPOSE: The purpose of this study was to investigate if prolonged neoadjuvant therapy, for locally advanced pancreatic cancer could be used to identify those patients who could benefit from resection surgery. METHODS: Thirty-four patients with locally advanced pancreatic cancer invading the adjacent major arteries underwent chemoradiotherapy, followed by 6 months of systemic chemotherapy, unless their tumor was already resectable. After this combination treatment, surgical resection was performed on those patients with tumors judged to be at least borderline resectable. RESULTS: Reevaluation after chemoradiotherapy revealed that, at that stage, surgery was only possible for one case; resection was successfully performed. Following 6 months of systemic chemotherapy, a further 7 patients were diagnosed with borderline resectable lesions; 4 underwent surgery with no postoperative complications. The median survival time of the patients following surgery was 3.63 years; this was reduced to approximately a third in patients not undergoing surgery (1.01 years; p = 0.0005). CONCLUSIONS: For patients with locally advanced pancreatic cancer, prolonged neoadjuvant therapy was successfully used to select candidates that could benefit from surgical resection of their tumor. Resection significantly increased the long-term survival rate.

The investigation of the survival time after recurrence in patients with pancreatic ductal adenocarcinoma for individualization of adjuvant chemotherapy.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease; however, the frequency of recurrence can be reduced if curative surgery following adjuvant chemotherapy is applied. At present, adjuvant chemotherapy is uniformly performed in all patients, as it is unclear which tumor types are controlled best or worst. We investigated patients with recurrence to establish the optimum treatment strategy. METHODS: Of 138 patients who underwent curative surgery for PDAC, 85 developed recurrence. Comprehensive clinicopathological factors were investigated for their association with the survival time after recurrence (SAR). RESULTS: The median SAR was 12.6 months. Treatments for recurrence included best supportive care, GEM-based therapy and S-1. The performance status [hazard ratio (HR) 0.12, P < 0.001], histological invasion of lymph vessels (HR 0.27, P < 0.001), kind of treatment for recurrence (HR 5.0, P < 0.001) and initial recurrence site (HR 2.9, P < 0.001) were independent significant risk factors for the SAR. The initial recurrence sites were the liver (n = 21, median SAR 8.8 months), lung (n = 10, 14.9 months), peritoneum (n = 6, 1.7 months), lymph nodes (n = 6, 14.7 months), local site (n = 17, 13.9 months) and multiple sites (n = 25, 10.1 months). A shorter recurrence-free survival (< 1 year) and higher postoperative CA19-9 level were significantly associated with critical recurrence (peritoneal/liver). CONCLUSIONS: Several risk factors for SAR were detected in this study. Further investigations are needed to individualize the adjuvant chemotherapy for each patient with PDAC.

[A Case of Repeated Surgical Resections for Tumor Seeding of Hepatocellular Carcinoma after Radiofrequency Ablation].

We report a case of repeated surgical resections for the tumor seeding of hepatocellular carcinoma(HCC)after radiofrequency ablation(RFA). A 79-year-old man, who had an intrahepatic recurrence of HCC(segment 2)5 months after RFA, was referred to our hospital for surgery, and underwent a laparoscopic lateral segmentectomy. Histological examination showed a poorly differentiated HCC(pStage II). Eight months after RFA, subcutaneous nodules along the RFA needle tract were pointed out by abdominal CT, and a tumorectomy was performed. Nineteen months after RFA, abdominal CT showed a 33mm tumor on the side of the spleen, leading to the diagnosis of the peritoneal dissemination following RFA. The tumor has been growing up to 49mm in size in spite of a radiation therapy. Accordingly, a laparoscopic tumorectomy was performed 26 months after RFA. His resected tumors were morphologically identical to the intrahepatic recurrence of HCC. The patient had remained recurrence-free for 4 months after the second tumorectomy. Our case demonstrated the utility of surgical resection for the tumor seeding of HCC following RFA.

MicroRNA-181b-5p, ETS1, and the c-Met pathway exacerbate the prognosis of pancreatic ductal adenocarcinoma after radiation therapy.

Preoperative chemoradiation therapy (CRT) for pancreatic ductal adenocarcinoma (PDAC) has emerged as a reasonable strategy that shows good prognostic impact. However, after preoperative CRT, resected specimens show remnant tumor cells, which indicate that some tumor cells had acquired or were selected for resistance to CRT. Recently, two oncological mechanisms, the EMT and the presence of CSCs, were reported to be associated with resistance in various cancers. Previous reports showed that HGF could induce EMT in PDAC cells; moreover, the HGF receptor, c-Met, was identified as a dominant pancreatic CSC marker. However, the clinical significance of c-Met expression remains unclear. So, we hypothesized that remnant PDAC tissue after CRT might harbor cells with high c-Met expression, and these cells may exacerbate patients' prognosis. In the immunohistochemical analysis, we showed that preoperative CRT was significantly associated with high c-Met expression; moreover, high c-Met expression was a significant marker of a dismal prognosis. Next, we investigated mechanisms of c-Met upregulation in PDAC cells. We established GEM-resistant and radioresistant PDAC cells to analyze the transcriptome involved in c-Met expression. The microarray data for the established radiation-resistant PDAC cells indicated miR-181b-5p downregulation, which targets ETS1, one of the transcription factors for c-Met, and it was shown that radiation exposure induced c-Met expression through ETS1 increase by the suppression of miR-181b-5p. These results suggested that targeting these mechanisms may promote the development of a novel multidisciplinary treatment strategy for improving preoperative CRT efficiency.

Patients Treated with Preoperative Chemoradiation for Pancreatic Ductal Adenocarcinoma have Impaired Bone Density, a Predictor of Distant Metastasis.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a lethal neoplasm that spreads to surrounding tissue or distant sites. This study investigated distant metastases in PDAC patients with or without preoperative chemoradiation therapy (CRT), focusing on vitamin D levels and bone density. METHODS: This study included 146 patients with PDAC who underwent surgery from 2007 to 2014. Bone density was evaluated using computed tomography, and the preoperative vitamin D level was calculated by enzyme-linked immunosorbent assay (ELISA) for patients with available plasma (48 cases). RESULTS: When the patients were divided into two groups according to the change in bone density, the group with decreased bone density had a shorter distant metastasis-free survival time (DMFS) after surgery than the other group (p < 0.05). Low vitamin D was a weak predictor of DMFS, but the difference was not significant (p = 0.08), perhaps because of the sample size. Multivariate analysis indicated three significant factors associated with distant metastasis: a decrease in bone density (hazard ratio [HR], 2.17; p = 0.04), normalization of the Dupan-2 value after surgery (hazard ratio [HR], 0.39; p = 0.02), and completion of adjuvant chemotherapy (HR, 0.29; p < 0.01). Univariate analysis showed that a low vitamin D concentration (<20 pg/ml) was a risk factor (p = 0.04) for bone density change. Multivariate analysis found that preoperative CRT was the only factor associated (±, OR, 5.8; p = 0.04) with bone density change, suggesting that preoperative CRT significantly decreases bone density in patients with insufficient vitamin D. CONCLUSION: Patients treated with preoperative CRT tend to have impaired bone density, which is a predictor of distant metastasis. Thus, vitamin D supplementation may decrease distant metastasis.

CT Density in the Pancreas is a Promising Imaging Predictor for Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Fatty pancreas (FP) was recently recognized as a risk factor for pancreatic ductal adenocarcinoma (PDAC). It is unclear whether computed tomography (CT) can be used to make a FP diagnosis. This study investigated whether CT could provide a predictive value for PDAC by diagnosing FP. METHODS: The study included 183 consecutive patients who underwent distal pancreatectomy from February 2007 to January 2017, including 75 cases of PDAC and 108 cases of other pancreatic disease. Pancreatic CT density (pancreatic index; PI) at the initial diagnosis was calculated by dividing the CT number in the pancreas by the number in the spleen. To assess whether CT could be used to detect FP, 43 cases were evaluated pathologically for FP. We investigated the correlation between FP and PI, and determined the optimal PI cutoff value for detecting FP using receiver operating characteristics analysis. We then investigated whether the PI value could be used as a predictor for PDAC. RESULTS: Fourteen cases (32.6%) were pathologically diagnosed with FP. PI was significantly lower in the FP group versus the non-FP group (0.51 vs. 0.83; p = 0.0049). ROC analysis indicated that the PI had good diagnostic accuracy for FP diagnosis (cutoff value 0.70; sensitivity 0.79, specificity 0.79). Low PI (≤0.70) was identified in the multivariate analysis as an independent risk factor for PDAC (odds ratio 2.31; p = 0.023). CONCLUSIONS: PI was strongly associated with pathological FP, which was independently associated with PDAC. PI shows promise as an imaging predictor for PDAC.