Wastewater-based reproduction numbers and projections of COVID-19 cases in three areas in Japan, November 2021 to December 2022.

BackgroundWastewater surveillance has expanded globally as a means to monitor spread of infectious diseases. An inherent challenge is substantial noise and bias in wastewater data because of the sampling and quantification process, limiting the applicability of wastewater surveillance as a monitoring tool.AimTo present an analytical framework for capturing the growth trend of circulating infections from wastewater data and conducting scenario analyses to guide policy decisions.MethodsWe developed a mathematical model for translating the observed SARS-CoV-2 viral load in wastewater into effective reproduction numbers. We used an extended Kalman filter to infer underlying transmissions by smoothing out observational noise. We also illustrated the impact of different countermeasures such as expanded vaccinations and non-pharmaceutical interventions on the projected number of cases using three study areas in Japan during 2021-22 as an example.ResultsObserved notified cases were matched with the range of cases estimated by our approach with wastewater data only, across different study areas and virus quantification methods, especially when the disease prevalence was high. Estimated reproduction numbers derived from wastewater data were consistent with notification-based reproduction numbers. Our projections showed that a 10-20% increase in vaccination coverage or a 10% reduction in contact rate may suffice to initiate a declining trend in study areas.ConclusionOur study demonstrates how wastewater data can be used to track reproduction numbers and perform scenario modelling to inform policy decisions. The proposed framework complements conventional clinical surveillance, especially when reliable and timely epidemiological data are not available.

Economic Evaluation of Wastewater Surveillance Combined with Clinical COVID-19 Screening Tests, Japan.

The COVID-19 pandemic has imposed substantial burdens on the global society. To find an optimal combination of wastewater surveillance and clinical testing for tracking COVID-19, we evaluated the economic efficiency of hypothetical screening options at a single facility in Japan. To conduct cost-benefit analyses, we developed standard decision models in which we assumed model parameters from literature and primary data, such as screening policies used at the Tokyo Olympic and Paralympic Village in 2021. We compared hypothetical 2-step screening options that used clinical PCR to diagnose COVID-19 after a positive result from primary screening using antigen tests (option 1) or wastewater surveillance (option 2). Our simulation results indicated that option 2 likely would be economically more justifiable than option 1, particularly at lower incidence levels. Our findings could help justify and promote the use of wastewater surveillance as a primary screening at a facility level for COVID-19 and other infectious diseases.

Near full-automation of COPMAN using a LabDroid enables high-throughput and sensitive detection of SARS-CoV-2 RNA in wastewater as a leading indicator.

Wastewater-based epidemiology (WBE) is a promising tool to efficiently monitor COVID-19 prevalence in a community. For WBE community surveillance, automation of the viral RNA detection process is ideal. In the present study, we achieved near full-automation of a previously established method, COPMAN (COagulation and Proteolysis method using MAgnetic beads for detection of Nucleic acids in wastewater), which was then applied to detect SARS-CoV-2 in wastewater for half a year. The automation line employed the Maholo LabDroid and an automated-pipetting device to achieve a high-throughput sample-processing capability of 576 samples per week. SARS-CoV-2 RNA was quantified with the automated COPMAN using samples collected from two wastewater treatment plants in the Sagami River basin in Japan between 1 November 2021 and 24 May 2022, when the numbers of daily reported COVID-19 cases ranged from 0 to 130.3 per 100,000 inhabitants. The automated COPMAN detected SARS-CoV-2 RNA from 81 out of 132 samples at concentrations of up to 2.8 × 105 copies/L. These concentrations showed direct correlations with subsequently reported clinical cases (5-13 days later), as determined by Pearson's and Spearman's cross-correlation analyses. To compare the results, we also conducted testing with the EPISENS-S (Efficient and Practical virus Identification System with ENhanced Sensitivity for Solids, Ando et al., 2022), a previously reported detection method. SARS-CoV-2 RNA detected with EPISENS-S correlated with clinical cases only when using Spearman's method. Our automated COPMAN was shown to be an efficient method for timely and large-scale monitoring of viral RNA, making WBE more feasible for community surveillance.

Identification of SARS-CoV-2 variants in wastewater using targeted amplicon sequencing during a low COVID-19 prevalence period in Japan.

Wastewater-based epidemiology is expected to be able to identify SARS-CoV-2 variants at an early stage via next-generation sequencing. In the present study, we developed a highly sensitive amplicon sequencing method targeting the spike gene of SARS-CoV-2, which allows for sequencing viral genomes from wastewater containing a low amount of virus. Primers were designed to amplify a relatively long region (599 bp) around the receptor-binding domain in the SARS-CoV-2 spike gene, which could distinguish initial major variants of concern. To validate the methodology, we retrospectively analyzed wastewater samples collected from a septic tank installed in a COVID-19 quarantine facility between October and December 2020. The relative abundance of D614G mutant in SARS-CoV-2 genomes in the facility wastewater increased from 47.5 % to 83.1 % during the study period. The N501Y mutant, which is the characteristic mutation of the Alpha-like strain, was detected from wastewater collected on December 24, 2020, which agreed with the fact that a patient infected with the Alpha-like strain was quarantined in the facility on this date. We then analyzed archived municipal wastewater samples collected between November 2020 and January 2021 that contained low SARS-CoV-2 concentrations ranging from 0.23 to 0.43 copies/qPCR reaction (corresponding to 3.30 to 4.15 log10 copies/L). The targeted amplicon sequencing revealed that the Alpha-like variant with D614G and N501Y mutations was present in municipal wastewater collected on December 4, 2020 and later, suggesting that the variant had already spread in the community before its first clinical confirmation in Japan on December 25, 2020. These results demonstrate that targeted amplicon sequencing of wastewater samples is a powerful surveillance tool applicable to low COVID-19 prevalence periods and may contribute to the early detection of emerging variants.

Wastewater-based prediction of COVID-19 cases using a highly sensitive SARS-CoV-2 RNA detection method combined with mathematical modeling.

Wastewater-based epidemiology (WBE) has the potential to predict COVID-19 cases; however, reliable methods for tracking SARS-CoV-2 RNA concentrations (CRNA) in wastewater are lacking. In the present study, we developed a highly sensitive method (EPISENS-M) employing adsorption-extraction, followed by one-step RT-Preamp and qPCR. The EPISENS-M allowed SARS-CoV-2 RNA detection from wastewater at 50 % detection rate when newly reported COVID-19 cases exceed 0.69/100,000 inhabitants in a sewer catchment. Using the EPISENS-M, a longitudinal WBE study was conducted between 28 May 2020 and 16 June 2022 in Sapporo City, Japan, revealing a strong correlation (Pearson's r = 0.94) between CRNA and the newly COVID-19 cases reported by intensive clinical surveillance. Based on this dataset, a mathematical model was developed based on viral shedding dynamics to estimate the newly reported cases using CRNA data and recent clinical data prior to sampling day. This developed model succeeded in predicting the cumulative number of newly reported cases after 5 days of sampling day within a factor of √2 and 2 with a precision of 36 % (16/44) and 64 % (28/44), respectively. By applying this model framework, another estimation mode was developed without the recent clinical data, which successfully predicted the number of COVID-19 cases for the succeeding 5 days within a factor of √2 and 2 with a precision of 39 % (17/44) and 66 % (29/44), respectively. These results demonstrated that the EPISENS-M method combined with the mathematical model can be a powerful tool for predicting COVID-19 cases, especially in the absence of intensive clinical surveillance.

Impact of the COVID-19 pandemic on the prevalence of influenza A and respiratory syncytial viruses elucidated by wastewater-based epidemiology.

Since the COVID-19 pandemic, a decrease in the prevalence of Influenza A virus (IAV) and respiratory syncytial virus (RSV) has been suggested by clinical surveillance. However, there may be potential biases in obtaining an accurate overview of infectious diseases in a community. To elucidate the impact of the COVID-19 on the prevalence of IAV and RSV, we quantified IAV and RSV RNA in wastewater collected from three wastewater treatment plants (WWTPs) in Sapporo, Japan, between October 2018 and January 2023, using highly sensitive EPISENS™ method. From October 2018 to April 2020, the IAV M gene concentrations were positively correlated with the confirmed cases in the corresponding area (Spearman's r = 0.61). Subtype-specific HA genes of IAV were also detected, and their concentrations showed trends that were consistent with clinically reported cases. RSV A and B serotypes were also detected in wastewater, and their concentrations were positively correlated with the confirmed clinical cases (Spearman's r = 0.36-0.52). The detection ratios of IAV and RSV in wastewater decreased from 66.7 % (22/33) and 42.4 % (14/33) to 4.56 % (12/263) and 32.7 % (86/263), respectively in the city after the COVID-19 prevalence. The present study demonstrates the potential usefulness of wastewater-based epidemiology combined with the preservation of wastewater (wastewater banking) as a tool for better management of respiratory viral diseases.

[A Case of Giant Abdominal Desmoid Tumor in a Young Man].

Desmoid tumor is a rare tumor of the soft tissue. The frequency of occurrence is 2.4 to 4.3 cases per year per million people, which is a very rare disease. We experienced a huge intra-abdominal desmoid tumor which is thought to be the primary mesentery. The case was a male in his 20s. He visited a nearby doctor with a complaint of abdominal bloating and abdominal pain. Abdominal contrast CT revealed a huge abdominal mass with a clear boundary of 35×25 cm in size extending from the upper right abdomen to the pelvis. Surgery was performed with a diagnosis of an intra-abdominal mass. Open abdominal tumor resection. Due to infiltration into the duodenum, transverse colon, and pancreas, right hemicolectomy and duodenal combined resection were performed. The pathological diagnosis was a diagnosis of desmoid tumor.

COPMAN: A novel high-throughput and highly sensitive method to detect viral nucleic acids including SARS-CoV-2 RNA in wastewater.

During the coronavirus disease 2019 (COVID-19) pandemic, wastewater-based epidemiology (WBE) attracted attention as an objective and comprehensive indicator of community infection that does not require individual inspection. Although several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection methods from wastewater have been developed, there are obstacles to their social implementation. In this study, we developed the COPMAN (Coagulation and Proteolysis method using Magnetic beads for detection of Nucleic acids in wastewater), an automatable method that can concentrate and detect multiple types of viruses from a limited volume (∼10 mL) of wastewater. The COPMAN consists of a high basicity polyaluminum chloride (PAC) coagulation process, magnetic bead-based RNA purification, and RT-preamplification, followed by qPCR. A series of enzymes exhibiting a high tolerance to PCR inhibitors derived from wastewater was identified and employed in the molecular detection steps in the COPMAN. We compared the detectability of viral RNA from 10-mL samples of virus-spiked (heat-inactivated SARS-CoV-2 and intact RSV) or unspiked wastewater by the COPMAN and other methods (PEG-qPCR, UF-qPCR, and EPISENS-S). The COPMAN was the most efficient for detecting spiked viruses from wastewater, detecting the highest level of pepper mild mottle virus (PMMoV), a typical intrinsic virus in human stool, from wastewater samples. The COPMAN also successfully detected indigenous SARS-CoV-2 RNA from 12 samples of wastewater at concentrations of 2.2 × 104 to 5.4 × 105 copies/L, during initial stages of an infection wave in the right and the left bank of the Sagami River in Japan (0.65 to 11.45 daily reported cases per 100,000 people). These results indicate that the COPMAN is suitable for detection of multiple pathogens from small volume of wastewater in automated stations.

[A Case of Liver Metastasis of Gastric Cancer Successfully Treated with SOX plus Nivolumab].

An 82-year-old, male. He visited his local doctor with a chief complaint of dyspnea on exertion. Anemia was noted, and upper gastrointestinal endoscopy was performed, which revealed an ulcerative lesion in the gastric antrum. A biopsy revealed Group 5, tub2, and HER2 negative, with PD-L1≥5%. cT3N1H1(M1 HEP), cStage ⅣB was diagnosed based on CT scan showing enlarged #8 lymph node and a single liver metastasis in the 2 cm range in S6 of the liver. The patient was deemed unresectable and was started on SOX plus nivolumab therapy. On day 11 after initiation, the patient had Grade 3 diarrhea by CTCAE v5.0, and S-1 was withdrawn for 3 days, but was administered for 2 courses. CT and MRI after chemotherapy showed shrinkage of both the primary tumor and liver metastases; R0 resection was deemed possible, and pyloric gastrectomy, D2 lymph node dissection, and partial hepatic S6 resection were performed. The histological evaluation of response to treatment was Grade 1b, and the patient was in ypStage ⅠA. The patient has been alive without recurrence for 6 months postoperatively while receiving S-1 monotherapy on an outpatient basis.

The detectability and removal efficiency of SARS-CoV-2 in a large-scale septic tank of a COVID-19 quarantine facility in Japan.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is known to be present in sewage, and wastewater-based epidemiology has attracted much attention. However, the physical partitioning of SARS-CoV-2 in wastewater and the removal efficiency of treatment systems require further investigation. This study aimed to investigate the detectability and physical partitioning of SARS-CoV-2 in wastewater and assess its removal in a large-scale septic tank employing anaerobic, anoxic, and oxic processes in a sequential batch reactor, which was installed in a coronavirus disease 2019 (COVID-19) quarantine facility. The amount of SARS-CoV-2 RNA in wastewater was determined with polyethylene glycol (PEG) precipitation followed by quantitative polymerase chain reaction (qPCR), and the association of SARS-CoV-2 with wastewater solids was evaluated by the effect of filtration prior to PEG precipitation (pre-filtration). The amount of SARS-CoV-2 RNA detected from pre-filtered samples was substantially lower than that of samples without pre-filtration. These results suggest that most SARS-CoV-2 particles in wastewater are associated with the suspended solids excluded by pre-filtration. The removal efficiency of SARS-CoV-2 in the septic tank was evaluated based on the SARS-CoV-2 RNA concentrations in untreated and treated wastewater, which was determined by the detection method optimized in this study. Escherichia coli and pepper mild mottle virus (PMMoV) were also quantified to validate the wastewater treatment system's performance. The mean log10 reduction values of SARS-CoV-2, E. coli, and PMMoV were 2.47 (range, 2.25-2.68), 2.81 (range, 2.45-3.18), and 0.66 (range, 0.61-0.70), respectively, demonstrating that SARS-CoV-2 removal by the wastewater treatment system was comparable to or better than the removal of fecal indicators. These results suggest that SARS-CoV-2 can be readily removed by the septic tank. This is the first study to determine the removal efficiency of SARS-CoV-2 in a facility-level sequencing batch activated sludge system.

The Efficient and Practical virus Identification System with ENhanced Sensitivity for Solids (EPISENS-S): A rapid and cost-effective SARS-CoV-2 RNA detection method for routine wastewater surveillance.

Wastewater-based epidemiology has attracted attention as a COVID-19 surveillance tool. Here, we developed a practical method for detecting SARS-CoV-2 RNA in wastewater (the EPISENS-S method), which employs direct RNA extraction from wastewater pellets formed via low-speed centrifugation. The subsequent multiplex one-step RT-preamplification reaction with forward and reverse primers for SARS-CoV-2 and a reverse primer only for pepper mild mottle virus (PMMoV) allowed for qPCR quantification of the targets with different abundances in wastewater from the RT-preamplification product. The detection sensitivity of the method was evaluated using wastewater samples seeded with heat-inactivated SARS-CoV-2 in concentrations of 2.11 × 103 to 2.11 × 106 copies/L. The results demonstrated that the sensitivity of the EPISENS-S method was two orders of magnitude higher than that of the conventional method (PEG precipitation, followed by regular RT-qPCR; PEG-QVR-qPCR). A total of 37 untreated wastewater samples collected from two wastewater treatment plants in Sapporo, Japan when 1.6 to 18 new daily reported cases per 100,000 people were reported in the city (March 4 to July 8, 2021), were examined using the EPISENS-S method to confirm its applicability to municipal wastewater. SARS-CoV-2 RNA was quantified in 92 % (34/37) of the samples via the EPISENS-S method, whereas none of the samples (0/37) was quantifiable via the PEG-QVR-qPCR method. The PMMoV concentrations measured by the EPISENS-S method ranged from 2.60 × 106 to 1.90 × 108 copies/L, and the SARS-CoV-2 RNA concentrations normalized by PMMoV ranged from 5.71 × 10-6 to 9.51 × 10-4 . The long-term trend of normalized SARS-CoV-2 RNA concentration in wastewater was consistent with that of confirmed COVID-19 cases in the city. These results demonstrate that the EPISENS-S method is highly sensitive and suitable for routine COVID-19 wastewater surveillance.

Mitochondrial glutathione peroxidase 4 is indispensable for photoreceptor development and survival in mice.

Glutathione peroxidase 4 (GPx4) is known for its unique function in the direct detoxification of lipid peroxides in the cell membrane and as a key regulator of ferroptosis, a form of lipid peroxidation-induced nonapoptotic cell death. However, the cytosolic isoform of GPx4 is considered to play a major role in inhibiting ferroptosis in somatic cells, whereas the roles of the mitochondrial isoform of GPx4 (mGPx4) in cell survival are not yet clear. In the present study, we found that mGPx4 KO mice exhibit a cone-rod dystrophy-like phenotype in which loss of cone photoreceptors precedes loss of rod photoreceptors. Specifically, in mGPx4 KO mice, cone photoreceptors disappeared prior to their maturation, whereas rod photoreceptors persisted through maturation but gradually degenerated afterward. Mechanistically, we demonstrated that vitamin E supplementation significantly ameliorated photoreceptor loss in these mice. Furthermore, LC-MS showed a significant increase in peroxidized phosphatidylethanolamine esterified with docosahexaenoic acid in the retina of mGPx4 KO mice. We also observed shrunken and uniformly condensed nuclei as well as caspase-3 activation in mGPx4 KO photoreceptors, suggesting that apoptosis was prevalent. Taken together, our findings indicate that mGPx4 is essential for the maturation of cone photoreceptors but not for the maturation of rod photoreceptors, although it is still critical for the survival of rod photoreceptors after maturation. In conclusion, we reveal novel functions of mGPx4 in supporting development and survival of photoreceptors in vivo.

Redundant roles of EGFR ligands in the ERK activation waves during collective cell migration.

Epidermal growth factor receptor (EGFR) plays a pivotal role in collective cell migration by mediating cell-to-cell propagation of extracellular signal-regulated kinase (ERK) activation. Here, we aimed to determine which EGFR ligands mediate the ERK activation waves. We found that epidermal growth factor (EGF)-deficient cells exhibited lower basal ERK activity than the cells deficient in heparin-binding EGF (HBEGF), transforming growth factor alpha (TGFα) or epiregulin (EREG), but all cell lines deficient in a single EGFR ligand retained the ERK activation waves. Surprisingly, ERK activation waves were markedly suppressed, albeit incompletely, only when all four EGFR ligands were knocked out. Re-expression of the EGFR ligands revealed that all but HBEGF could restore the ERK activation waves. Aiming at complete elimination of the ERK activation waves, we further attempted to knockout NRG1, a ligand for ErbB3 and ErbB4, and found that NRG1-deficiency induced growth arrest in the absence of all four EGFR ligand genes. Collectively, these results showed that EGFR ligands exhibit remarkable redundancy in the propagation of ERK activation waves during collective cell migration.

[A Case of Primary Hepatic Mucosa-Associated Lymphoid Tissue Lymphoma].

A 74-year-old man with no chronic liver disease was admitted for an incidental liver tumor by computed tomography. Serological examinations for hepatitis B and C virus were negative and tumor markers, including carcinoembryonic antigen, α-fetoprotein, carbohydrate antigen 19-9, and des-gamma-carboxy prothrombin, were within the normal range. The contrast- enhanced magnetic resonance imaging revealed that the 26 mm in diameter patchy tumor occupied the S7 in the liver. The tumor boundary was enhanced slightly in the arterial phase and inside gradually in the portal phase, and the enhancement was faded in the late phase. As a characteristic finding, vessels penetrated the tumor. The tumor was diagnosed as cholangiocarcinoma, and the patient underwent right lateral sectionectomy. After 19 days postoperatively, the patient was discharged. The diagnosis of hepatic mucosa-associated lymphoid tissue(MALT)lymphoma was made by pathological examination. Currently, the patient has no recurrence for 5 months without adjuvant chemotherapy. The primary hepatic MALT lymphoma is a rare disease among primary hepatic malignant lymphomas. The patient must be followed up carefully because 2 cases were reported as recurrent cases after several years postoperatively although the disease has a good prognosis.

[A Case of Laparoscopically Resected Sigmoid Colon Cancer and Transverse Colon Mesentery Primary Solitary Fibrous Tumor].

The patient is a 52-year-old woman who visited the general practitioner because of positive fecal occult blood test by medical examination. The patient underwent colonoscopy at the hospital, which revealed sigmoid colon cancer. Therefore, the patient was referred to our hospital for surgery. Preoperative CT scan revealed a well-defined and lobulated 54 mm tumor on the caudal side of the duodenal third portion. On MRI, the tumor showed low T1-weighted image signal and high T2-weighted and diffusion-weighted images signal, with low ADC. For preoperative diagnosis, we diagnosed sigmoid colon cancer and transverse colon mesenteric and performed laparoscopic sigmoid colon and transverse colon mesenteric tumor resections. The histopathological tumor diagnoses were sigmoid colon cancer(S, type 2, 30×30 mm, 1/2 circumference, moderately differentiated adenocarcinoma, pT3[SS], INF b, Ly1a, V1a, pN1b[#252: 2/4], sM0, fStage Ⅲb)and transverse colon mesentery primary solitary fibrous tumor. The patient was treated with XELOX as the adjuvant chemotherapy and survived without recurrence until present.

[Long-Term Survival following Multidisciplinary Therapy for Unresectable Pancreatic Body Cancer].

A 57-year-old man was diagnosed with a tumor in the pancreatic body at a nearby hospital and consulted our hospital. Examinations revealed that carbohydrate antigen 19-9(CA19-9)levels were 1,765.0 U/mL. We confirmed metastatic liver tumors in S4 and S8 of the liver by EOB-MRI. We diagnosed unresectable pancreatic cancer(T3N0M1, cStage Ⅳ)and administered 10 courses of gemcitabine(GEM)plus nab-paclitaxel(nab-PTX)therapy. The main lesion and the lesion in S4 subsequently disappeared, and the lesion in S8 degenerated into a cyst. CA19-9 levels were 113 U/mL. Surgery was determined as the best course of action after normalizing CA19-9 levels. Therefore, we further administered 6 courses of FOLFIRINOX therapy and 4 courses of GEM plus nab-PTX therapy, but CA19-9 was not normalized. We decided that it would be difficult to normalize CA19-9, and thus proceeded with surgery. During the operation, cystic degenerative lesions were found in S8 and peritoneal dissemination was found in the transverse mesentery. Because the ascites cytopathology was negative, it was judged that the peritoneal dissemination was localized. We performed distal pancreatectomy(D2)plus partial hepatectomy(S8)plus peritoneal dissemination resection. On day 52 after surgery, we resumed GEM plus nab-PTX. The patient has survived without any recurrence for 3 years after the initial surgery.

[A Case of Giant Pancreatic Mucinous Cystic Neoplasm That Was Difficult to Preoperative Diagnosis].

A 43-year-old woman with about abdominal distension was referred to our hospital for a more detailed examination. Abdominal CT showed 27 cm-sized cystic lesion with the calcification along the partition wall and a nodular hyperplasia. We suspected pancreatic pseudocyst, primary retroperitoneal tumor and we performed tumorectomy. The resected specimen had a maximum diameter of 27 cm. The histopathological diagnosis was mucinous cystadenocarcinoma of the pancreas with ovarian-type stroma. The adjuvant chemotherapy treated with gemcitabine was selected for 3 courses. She continues to do well without any recurrences 7 months later.

[A Case of Gastric Cancer Performed Curative Operation after Nivolumab].

A 69-year-old man was admitted for the severe anemia. Upper gastrointestinal endoscopy revealed type 3 gastric cancer (por1, HER2 negative)that spread from EG junction to the lesser curvature of lower gastric body. CT revealed LNs metastasis and the direct invasion to the diaphragm. We diagnosed the locally advanced gastric cancer(T4bN[+]M0, Stage ⅣA) and planed neoadjuvant chemotherapy. After 3 courses of S-1 plus CDDP therapy, serum CEA level increased. And the invasion to diaphragm was unclear although the tumor shrunk. After 3 courses of nab-PTX plus RAM therapy as the second- line, the tumor was PD. As the third-line chemotherapy, nivolumab therapy was repeated up to a total of 15 courses. As the tumor was PR, the patient underwent total gastrectomy with D2 lymphadenectomy. The histopathological examination revealed that the cancer invaded into the muscle layer without lymph nodes metastasis. The cancer was diagnosed as pT2 (MP)N0M0, Stage ⅠB. The cancer cells were EB virus positive and MSI-high. CD 8 positive T lymphocytes infiltrated into the stroma. The patient is alive 26 months without adjuvant chemotherapy. The curative operation was able to perform because the infiltrative CD8 positive T lymphocytes reactivated with nivolumab responded remarkably.

[A Case of Pancreas Neuroendocrine Carcinoma Achieved Long-Term Survival by Carboplatin plus Etoposide Therapy].

A 70-year-old man with the history of diabetes mellitus complained of lower abdominal discomfort. Abdominal ultrasonography revealed a pancreatic mass. Contrast enhanced CT showed a 2.6 cm-enhanced tumor ventral to the pancreatic head. It was diagnosed with a pancreatic neuroendocrine carcinoma(PanNEC-G3)by EUS-FNA. The patient underwent pancreatoduodenectomy with the wedge resection of the portal vein and partial resection of the transverse colon. We administered 6 cycles of adjuvant therapy with CDDP plus CPT-11. With the presentation of lymph node metastases and the local recurrence in the anastomotic site of the transverse colon 15 months after surgery, the patient received carboplatin plus etoposide(CE)therapy. Although local recurrence completely responded to the CE therapy, bone metastases were detected 27 months after surgery. Metastatic lesion did not respond to systemic chemotherapy including gemcitabine plus nab-paclitaxel and nal-IRI plus 5-FU/LV, and the patient eventually died 37 months after the surgery. PanNECs represent for less than 1% of all pancreatic tumor. They are characterized by high malignant potential and short time survival with the reported OS of 8.5 to 21 months. This case served as an important reminder to consider multimodal treatment for PanNEC patients to obtain longer survival.