Published papers

Biliary complications after hepatectomy in living donors have yet to be eradicated. We hypothesized that a standardized upfront Glissonean approach and liver hanging maneuver (GH) would prevent mechanical and thermal injuries to the hilar plate of the remnant liver by determining the point of bile duct division and the final destination of hepatectomy preceding liver parenchymal transection (safety) and facilitate liver transection deep within the parenchyma and allow maximum length of hilar structures (rationality). GH was implemented in 2016 and its incidence of bile leakage was retrospectively compared against the conventional technique. GH comprises six steps: (1) development of the retrohepatic avascular plane between the right hepatic vein (RHV) and the middle hepatic vein (MHV) and isolation of the hepatic vein(s); (2) isolation of the right or left Glissonean pedicle with the corresponding Glissonean pedicles of the caudate lobe; (3) for right liver grafts and left liver grafts with the caudate lobe, passage of the tape for the liver hanging maneuver along the retrohepatic avascular plane and above the hilar plate, and for left liver grafts without the caudate lobe and for left lateral section grafts, passage of the tape from between the RHV and the MHV, along the Arantius ligament, and to the right of the umbilical portion; (4) liver transection; (5) isolation of hilar structures; and (6) graft procurement. Until 2020, 62 consecutive living donors underwent GH (success rate, 100%). The incidence of bile leakage from the hepatic hilum (0%) was significantly lower than that among 59 donors who underwent the conventional technique in 2011–2015 (9%; p = 0.01). In conclusion, GH is highly effective in reducing bile leakage from the hepatic hilum in living donors.

Background: Although the effectiveness of epidural anesthesia on pain control after esophagectomy has been reported, the appropriate insertion level of the epidural catheter remains unclear for adequate postoperative pain control. We investigated the relationship between the epidural catheter insertion level and postoperative pain control after esophagectomy for esophageal cancer. Methods: We analyzed retrospectively 63 patients who underwent McKeown esophagectomy for esophageal cancer between October 2014 and November 2018. The epidural catheter was inserted at the T4–T10 level before general anesthesia induction, and epidural anesthesia was started during the operation. In the analysis, the epidural catheter insertion level was divided into three groups (over T6/T7, T7/T8, and under T8/T9) and determined. Postoperative pain was evaluated a numeric rating scale (NRS) for at least 7 postoperative days, and the first NRS after extubation was used to evaluate the impact of the epidural catheter insertion level on pain control. Results: Ten patients (15.9%) failed pain control. The χ2 test and a forward stepwise logistic regression analysis revealed that only the epidural catheter insertion level affected pain control (P < 0.05). The T7/T8 insertion level significantly decreased postoperative pain after esophagectomy. In the subgroup analysis, epidural catheter insertion under T8/T9 significantly increased postoperative pain after esophagectomy when thoracoscopy/laparoscopy was assisted. No significant differences were observed in the incidence of postoperative complications among the epidural catheter insertion levels. Conclusions: The T7/T8 epidural catheter insertion level contributed to postoperative pain relief and could lead to enhanced recovery after esophagectomy for esophageal cancer.

Introduction: von Hippel-Lindau disease (vHL disease) is a hereditary disease in which tumors and cysts develop in many organs, in association with central nervous system hemangioblastomas, pheochromocytomas, and pancreatic tumors. We herein report a case of vHL disease (type 2A) associated with bilateral pheochromocytomas, pancreatic neuroendocrine tumors (PNET), and cerebellar hemangioblastomas treated via pancreatectomy after adrenalectomy. Case presentation: A 51-year-old woman presented with a cerebellar tumor, bilateral hypernephroma, and pancreatic tumor detected during a medical checkup. 18F-fluorodeoxyglucose positron emission tomography–computed tomography revealed a bilateral adrenal gland tumor and a tumor in the head of the pancreas, while an abdominal computed tomography examination revealed a 30-mm tumor with strong enhancement in the head of the pancreas. Cranial magnetic resonance imaging showed a hemangioblastoma in the cerebellum. Therefore, a diagnosis of vHL disease (type 2A) was made. Her family medical history included renal cell carcinoma in her father and bilateral adrenal pheochromocytoma and spinal hemangioblastoma in her brother. A detailed examination of endocrine function showed that the adrenal mass was capable of producing catecholamine. Treatment of the pheochromocytoma was prioritized, and therefore, laparoscopic left adrenalectomy and subtotal resection of the right adrenal gland were performed. Once the postoperative steroid levels were replenished, subtotal stomach-preserving pancreatoduodenectomy was performed for the PNET. After a good postoperative course, the patient was discharged in remission on the 11th day following surgery. Histopathological examination findings indicated NET G2 (MIB-1 index 10–15%) pT3N0M0 Stage II A and microcystic serous cystadenoma throughout the resected specimen. The patient is scheduled to undergo treatment for the cerebellar hemangioblastoma. Conclusion: A two-staged resection is a safe and effective treatment option for bilateral pheochromocytoma and PNET associated with vHL disease.

The selective arterial calcium injection (SACI) test is useful for patients with functional pancreatic neuroendocrine tumors (F-PNETs). This study evaluated which patients with F-PNETs would benefit from the SACI test. We retrospectively analyzed the preoperative findings of patients on computed tomography (CT), magnetic resonance imaging (MRI), CT angiography (CTA), and the SACI test. Fourteen patients who underwent pancreatectomy between January 1997 and September 2016 for F-PNETs were evaluated. We classified these patients into groups A, B, and C; group A, one tumor detected by either CT or MRI; group B, multiple tumors detected; and group C, the tumor location was accordant on CT, MRI, and CTA, but the SACI test revealed another tumor. In group A, the tumor was also detected by CTA and the SACI test was positive on calcium injection. In group B, the focus tumor among the multiple tumors was detected by the SACI test. In group C, another tumor was identified by the SACI test, whose location was different from that detected using CT and MRI. The SACI test is more useful for multiple F-PNETs on CT or MRI. If CT or MRI detects a single tumor, the SACI test or CTA may be unnecessary.

The patient was an 81-year-old man. Laparoscopic sigmoidectomy was performed for a sigmoid colon cancer (S, type 2, pT3 [SS], INF a, Ly0, V0, BD1, Pn0, pPM0, pDM0, RM0, pN0, pM0, pStage IIIa, R0, Cur A). One year after the surgery, a blood test showed CEA as high as 68.9 ng/mL, and an abdominal enhanced computed tomography revealed a hepatic tumor showing marginal contrast in the 4th liver segment. Positron emission tomography showed an accumulation of SUVmax 19.0 at the same site, and a metastatic liver tumor was diagnosed. A laparoscopic medial hepatectomy was performed. Bleeding from the hepatectomy site increased significantly after completion. Subcutaneous emphysema spreading from the face to the trunk and thigh was observed, and blood tests revealed a pH of 7.172, PaCO2of 71.0 mmHg, lactate of 67 mg/dL, mixed acidosis, D-dimer of 118 μg/mL, and a disseminated intravascular coagulation (DIC) syndrome was diagnosed. Following the difficulty of hemostasis, the surgery was changed to laparotomy and terminated by gauze packing. We encountered a case of acidosis exacerbated by hypercapnia that progressed to DIC during laparoscopic medial hepatectomy.

The patient was a 62-year-old man with no specific medical history. Lateral segmentectomy was performed for hepatocellular carcinoma with a tumor size of approximately 14×13 cm. The histopathological diagnosis was moderately differentiated hepatocellular carcinoma: Fc (-), Fc-lnf (-), Sf (-), SO, NO, Vp2, Vv1, VaO, BO, PO, SM (-), CH. Five years after the first surgery, computed tomography (CT) revealed a left lung tumor in segment 9/10 and left lymph nodes; thus, left pneumonectomy was performed, and these tumors were identified to have metastasized from the primary tumor. Six years after the first surgery, his serum alpha-fetoprotein level was remarkably elevated from 254.9 ng/mL to 3,143.0 ng/mL for three months, and at the same time, he developed left meralgia and swelling of the left femur. Magnetic resonance imaging showed a high-density mass (30×14 cm) in the left quadriceps, and positron emission tomography-CT revealed high uptake in the left quadriceps with a maximum standardized uptake value of 12.3. A needle biopsy of the left femur tumor confirmed metastasis from the primary tumor. Radiotherapy was administered because general anesthesia can prove to be hazardous due to the patient having undergone left pneumonectomy.

Objectives Cryoablation is a potentially less invasive locoregional ablation modality. Although cryoablation has been used to treat malignancy in various organs, a limited application of this modality in the pancreas has been reported. Methods Acute phase response assessments and postprocedural course evaluations of 2 experimental locoregional ablation methods were conducted. In one method, open and laparoscopic cryoablation of a porcine pancreas using an argon-helium gas-based cryoablation system and monitoring of tissue temperature during the procedure were performed. In the other method, open cryoablation of a porcine pancreas using liquid nitrogen was performed. The animals were evaluated postoperatively. Results The size of the cryolesion was larger in the second treatment than in the first. Laparoscopic cryoablation was associated with the formation of an iceball, which possibly affected the surrounding structures. The ablated region was adequately cooled with 10 minutes of freeze/repeat cycles. The area cooled to a temperature of less than -40°C was approximately half the size of the cryolesion in diameter. The swine used for the evaluation of the postprocedural course survived 3 weeks after the procedure with a temporal elevation of the serum lipase level. Conclusions Cryoablation of the pancreas was experimentally practicable without severe complications under direct or laparoscopic vision.

BACKGROUND Cytomegalovirus (CMV) remains a critical complication after solid-organ transplantation. The CMV antigenemia (AG) test is useful for monitoring CMV infection. Although the AG-positivity rate in CMV gastroenteritis is known to be low at onset, almost all cases become positive during the disease course. We treated a patient with transverse colon perforation due to AG-negative CMV gastroenteritis, following a living donor liver transplantation (LDLT). CASE SUMMARY The patient was a 52-year-old woman with decompensated liver cirrhosis as a result of autoimmune hepatitis who underwent a blood-type compatible LDLT with her second son as the donor. On day 20 after surgery, upper and lower gastrointestinal endoscopy (GE) revealed multiple gastric ulcers and transverse colon ulcers. The biopsy tissue immunostaining confirmed a diagnosis of CMV gastroenteritis. On day 28 after surgery, an abdominal computed tomography revealed transverse colon perforation, and simple lavage and drainage were performed along with an urgent ileostomy. Although the repeated remission and aggravation of CMV gastroenteritis and acute cellular rejection made the control of immunosuppression difficult, the upper GE eventually revealed an improvement in the gastric ulcers, and the biopsy samples were negative for CMV. The CMV-AG test remained negative, therefore, we had to evaluate the status of the CMV infection on the basis of the clinical symptoms and GE. CONCLUSION This case report suggests a monitoring method that could be useful for AG-negative CMV gastroenteritis after a solid-organ transplantation.

Formalin-fixed paraffin-embedded (FFPE) tissues used for routine pathological diagnosis are valuable for cancer genomic analysis; however, the association between mutation status derived from these specimens and prognosis in pancreatic ductal adenocarcinoma (PDAC) remains unclear. We analyzed 50 cancer-related gene mutations including driver genes in PDAC, using next-generation sequencing (NGS) to clarify the association between gene mutations and prognosis. DNA was extracted from FFPE tissues obtained from 74 patients with untreated resectable PDAC who underwent surgery at our institution between 2013 and 2018. Fifty of the 74 patients with DNA extracts from FFPE samples suitable for NGS were analyzed. The prevalence of driver gene mutations was as follows: 84% for KRAS, 62% for TP53, 32% for SMAD4, and 18% for CDKN2A. There were no cases of single SMAD4 mutations; its rate of coincidence with KRAS or TP53 mutations was 30% and 2%, respectively. The combination of KRAS and SMAD4 mutations resulted in significantly shorter relapse-free survival (RFS; median survival time [MST], 12.3 vs. 28.9 months, P =.014) and overall survival (OS; MST, 22.3 months vs. not reached, P =.048). On multivariate analysis, the combination of KRAS and SMAD4 mutations was an independent prognostic factor for RFS (hazard ratio [HR] 4.218; 95% confidence interval [CI], 1.77-10.08; P =.001) and OS (HR 6.730; 95% CI, 1.93-23.43; P =.003). The combination of KRAS and SMAD4 mutations in DNA obtained from FFPE tissues is an independent poor prognostic factor in PDAC.

Human induced pluripotent stem cells (hiPSCs) are a promising cell source for elucidating disease pathology and therapy. The mass supply of hiPSC-derived cells is technically feasible. Carriers that can contain a large number of hiPSC-derived cells and evaluate their functions in vivo-like environments will become increasingly important for understanding disease pathogenesis or treating end-stage organ failure. hiPSC-derived hepatocyte-like cells (hiPSC-HLCs; 5 × 108) were seeded into decellularized organ-derived scaffolds under circumfusion culture. The scaffolds were implanted into immunodeficient microminiature pigs to examine their applicability in vivo. The seeded hiPSC-HLCs demonstrated increased albumin secretion and up-regulated cytochrome P450 activities compared with those in standard two-dimensional culture conditions. Moreover, they showed long-term survival accompanied by neovascularization in vivo. The decellularized organ-derived scaffold is a promising carrier for hiPSC-derived cells for ex vivo and in vivo use and is an essential platform for regenerative medicine and research.

Background: We aimed to evaluate the efficacy and safety of 5-fluorouracil-based neoadjuvant chemoradiotherapy (NACRT) in patients with resectable/borderline resectable pancreatic ductal adenocarcinoma (PDAC). Methods: This retrospective study investigated the clinicopathological features and > 5-year survival of patients with T3/T4 PDAC who underwent NACRT at our institute between 2003 and 2012. Results: Seventeen resectable and eight borderline resectable patients were included. The protocol treatment completion and resection rates were 92.0% and 68.0%, respectively. Two patients failed to complete chemotherapy owing to cholangitis or anorexia. Common grade 3 toxicities included anorexia (12%), neutropenia (4%), thrombocytopenia (4%), anemia (4%), and leukopenia (12%). Pathologically negative margins were achieved in 94.1% of patients who underwent pancreatectomy. Pathological response according to Evans' classification was grade IIA in 10 patients (58.8%), IIB in 5 patients (29.4%), and IV in 2 patients (11.8%). Postoperative pancreatic fistulas were observed in four patients (23.5%), delayed gastric emptying in one patient (5.9%), and other operative morbidities in four patients (23.5%). The 1-, 2-, 5-, and 10-year overall survival rates were 73.9%, 60.9%, 60.9%, and 39.1%, respectively (median follow-up period, 80.3 months). Conclusions: NACRT is tolerable and beneficial for resectable/borderline resectable PDAC, even in the long-term.

Objectives The aim of this study was to determine whether computer-assisted digital analysis and acoustic radiation force impulse (ARFI) imaging were useful for assessing pancreatic fibrosis, and if ARFI imaging predicted postoperative pancreatic fistula (POPF). Methods Seventy-eight patients scheduled to undergo pancreatic resection were enrolled. Shear wave velocity (SWV) at the pancreatic neck was measured preoperatively using ARFI imaging. Pancreatic tissue components on a whole slide image were quantified using an automatic image processing software. The relationship between SWV, fibrotic tissue content, and POPF incidence and clinical severity was analyzed. Results The median collagen fiber, fatty tissue, and acinar cell contents were 11.6%, 8.5%, and 61.3%, respectively. Unlike fatty tissue, collagen fiber content and acinar cells were correlated with SWV (ρ = 0.440, P < 0.001 and ρ =-0.428, P < 0.001, respectively). Although collagen fiber content and SWV were associated with the overall incidence of POPF (P = 0.004 and 0.001, respectively), collagen fiber content and SWV had no statistical correlation with clinically relevant POPF (P = 0.268 and 0.052, respectively). Conclusions We objectively quantified the pancreatic tissue components using an automatic image processing software. Shear wave velocity was significantly related to collagen fiber content and suggests that ARFI imaging can be useful for evaluating pancreatic fibrosis.

Background: Outflow control is difficult, and techniques required for effectively handling intraoperative hemorrhage during laparoscopic hepatectomy have not previously been adequately reported. Methods: Sixteen patients underwent surgery, of which 15 underwent laparoscopic left hepatectomy and one underwent laparoscopic partial hepatectomy of the caudate lobe. Encircling and taping of the common trunk of the middle (MHV) and left hepatic veins (LHV) was performed in 12 patients, and that of the LHV alone in four patients. Surgical techniques based on anatomical landmarks and histological findings are presented with videos. Histological confirmation of the anatomical landmarks for these procedures was performed in fresh cadavers to understand the anatomical structures and layers involved. Results: The median procedure duration was 15 (6-25) minutes. All procedures were performed safely with no major bleeding. Histological findings showed fibrous connective tissue between the tunica adventitia of the inferior vena cava (IVC) and the Laennec’s capsule of the liver. The layer of dissection was along the tunica adventitia of the IVC. Conclusions: The surgical techniques for encircling and taping of the common trunk of the MHV and LHV and the LHV alone based on anatomical landmarks were feasible and could allow for efficient outflow control in laparoscopic hepatectomy.

Background: Frailty results in a high risk for disability, hospitalization, and mortality. This study aimed to investigate perioperative details of frail patients who underwent pancreatectomy and whether frailty can be a predictive factor of postoperative complications, especially of clinically relevant postoperative pancreatic fistula (CR-POPF). Methods: This retrospective study included patients who underwent pancreatectomy in our hospital between August 2016 and March 2019. The patients were divided into frail and pre-/non-frail groups. The diagnostic criteria were based on the Japanese version of the Cardiovascular Health Study. Results: Of 93 patients, 11 (11.8%) and 82 (88.2%) were frail and pre-/non-frail patients, with median ages of 82 and 72 years, respectively (p = 0.041). Postoperative complications (Clavien-Dindo ≧ IIIa) were found in 8 and 32 patients (p = 0.034), CR-POPF in 3 and 13 patients (p = 0.346), and postoperative hospital stays were 21 and 17 days (p = 0.041), respectively. On multivariate analysis, frailty was an independent predictive factor (odds ratio [OR] 5.604, 95.0% confidence interval [CI] 1.002-30.734; p = 0.047) of postoperative complications (Clavien-Dindo ≧ IIIa) after pancreaticoduodenectomy. On multivariate analysis, a soft pancreas (OR 5.696, 95.0% CI 1.142-28.149; p = 0.034) was an independent and significant predictive factor of CR-POPF after pancreaticoduodenectomy. Conclusions: Frailty may be a useful predictive factor of postoperative complications in patients undergoing pancreaticoduodenectomy.

Environmental and genetic factors play a critical role in the pathogenesis of pancreatic cancer, which is likely to follow a multistep process that includes intraductal papillary mucinous neoplasm. The pathogenesis of familial pancreatic cancer has been reported; however, epidemiological characteristics and causative genes remain unclear. This study aimed to determine the relationship between the family history of pancreatic cancer and tumor malignancy and identify novel susceptible germline variants of pancreatic cancer. We performed an epidemiologic study at our institute on a cohort of 668 patients with intraductal papillary mucinous neoplasm and 242 with pancreatic cancer but without associated intraductal papillary mucinous neoplasm stratified by family history of pancreatic cancer. Whole-exome sequencing was conducted for 10 patients from seven families with familial pancreatic cancer and intraductal papillary mucinous neoplasm. We found that patients who had intraductal papillary mucinous neoplasm with positive family history of pancreatic cancer within first-degree relatives were more likely to develop malignancy in a shorter period than those without family history. Duplicate frameshift variants in TET2 c.3180dupG (p.Pro1061fs) and ASXL1 c.1934dupG (p.Gly646fs) in one family and POLN c.1194dupT (p.Glu399fs) in another were identified as pathogenic truncating germline variants which were previously recognised susceptibility genes. Moreover, PDIA2 c.1403C>T (p.Pro468Leu) and DPYSL4 c.926C>A (p.Pro309Gln) were shared in four and two patients, respectively. In particular, PDIA2 was identified as a novel candidate for one of the deleterious variants of familial pancreatic cancer.

Background/Objectives: According to the revised international intraductal papillary mucinous neoplasm (IPMN) guidelines (2017), the indication for surgery is based on risk classification. However, some IPMNs with high-risk stigmata (HRS) can be observed for long periods without resection. Hence, we need to reconsider the risk stratification, and this study aimed to propose a novel risk stratification for HRS-IPMNs. Methods: We enrolled 328 patients diagnosed with IPMN using endoscopic ultrasound between 2012 and 2019. We compared clinicopathological features between HRS and worrisome features (WF) and evaluated outcomes of HRS-IPMN. Results: Fifty-three patients (HRS 38, WF 15) underwent resection at initial diagnosis and 275 patients were observed. Following observation for 30 months, 22 patients (17 HRS, 5 WF) underwent resection. Analysis of resected IPMNs (n = 75) revealed that HRS had dominantly pancreatobiliary mucin subtype. Pancreatobiliary-type IPMN had larger nodule sizes and lymphatic invasion and high recurrence with poor prognosis. Seventy-four patients were diagnosed with HRS, 55 underwent resection, and 19 continue to be observed. The resected group had larger nodule sizes (median 8 mm vs. 5 mm; P = 0.060), whereas the observed group had more main pancreatic duct (MPD) dilation (median 10 mm vs. 5 mm; P = 0.005). In the resected HRS group, only patients with MPD dilation ≥10 mm (n = 10) had no recurrence but had a favorable prognosis compared with those nodule size ≥5 mm (n = 45). Conclusions: Large nodule size may be associated with pancreatobiliary subtype and poor prognosis; however, patients with MPD dilation ≥10 mm with nodule size <5 mm did not require resection.

Background/Aim: Pancreatic cancer, which exhibits resistance to cytotoxic and molecular targeted drugs, has an extremely poor prognosis. Nuclear factor-ĸB (NF-ĸB) is constitutively activated in many pancreatic cancer cases. Although the NF-ĸB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) has exhibited anti-cancer effects in pancreatic cancer models, its poor solubility limits its use to intraperitoneal administration. Materials and Methods: Poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (PMB) forms stable polymer aggregates with DHMEQ. The stability of DHMEQ aggregated with PMB in the human blood was measured by high-performance liquid chromatography–mass spectrometry (HPLC-MS) ex vivo. Anti-pancreatic cancer effects in AsPC-1 and MIA PaCa-2 pancreatic cancer cells were evaluated by cell growth inhibition assay in vitro and tumor growth inhibition assay in vivo. Results: DHMEQ aggregated with PMB (PMBDHMEQ) remained detectable after 60 min of incubation in the human blood, whereas DHMEQ aggregated with carboxymethyl cellulose (CMC-DHMEQ) was barely detectable. PMB-DHMEQ significantly inhibited AsPC-1 and MIA PaCa-2 cell growth in vitro compared to CMC-DHMEQ. Intravenous administration of PMB-DHMEQ reduced the tumor volume and liver metastasis compared to untreated or CMC-DHMEQ-treated mice. Conclusion: Aggregation with PMB improved the solubility of DHMEQ, and effectively inhibited pancreatic cancer cell growth both in vitro and in vivo.

Background:Pancreatic ductal adenocarcinoma (PDAC) has very poor prognosis despite existing multimodal therapies. This study aimed to investigate whether KRAS mutations at codons 12/13 in cell-free DNA (cfDNA) from preoperative and postoperative sera from patients with PDAC can serve as a predictive biomarker for treatment response and outcomes after surgery.Methods:Preoperative and postoperative serum samples obtained from 45 patients with PDAC whom underwent curative pancreatectomy at our institution between January 2013 and July 2016 were retrospectively analysed. Peptide nucleic acid-directed PCR clamping was used to identify KRAS mutations in cfDNA.Results:Among the 45 patients enrolled, 11 (24.4%) and 20 (44.4%) had KRAS mutations in cfDNA from preoperative and postoperative sera, respectively. Multivariate analysis revealed that KRAS mutations in postoperative serum (hazard ratio (HR)=2.919; 95% confidence interval (CI)=1.109-5.621; P=0.027) are an independent prognostic factor for disease-free survival. Furthermore, the shift from wild-type KRAS in preoperative to mutant KRAS in postoperative cfDNA (HR=9.419; 95% Cl=2.015-44.036; P=0.004) was an independent prognostic factor for overall survival.Conclusions:Changes in KRAS mutation status between preoperative and postoperative cfDNA may be a useful predictive biomarker for survival and treatment response.

KRAS mutation is a major driver of pancreatic carcinogenesis and will likely be a therapeutic target. Due to lack of sensitive assays for clinical samples of pancreatic cancer with low cellularity, KRAS mutations and their prognostic association have not been fully examined in large populations. In a multi-institutional cohort of 1162 pancreatic cancer patients with formalin-fixed paraffin-embedded tumor samples, we undertook droplet digital PCR (ddPCR) for KRAS codons 12/13/61. We examined detection rates of KRAS mutations by clinicopathological parameters and survival associations of KRAS mutation status. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for disease-free survival (DFS) and overall survival (OS) were computed using the Cox regression model with adjustment for potential confounders. KRAS mutations were detected in 1139 (98%) patients. The detection rate did not differ by age of tissue blocks, tumor cellularity, or receipt of neoadjuvant chemotherapy. KRAS mutations were not associated with DFS or OS (multivariable HR comparing KRAS-mutant to KRAS-wild-type tumors, 1.04 [95% CI, 0.62–1.75] and 1.05 [95% CI, 0.60–1.84], respectively). Among KRAS-mutant tumors, KRAS variant allele frequency (VAF) was inversely associated with DFS and OS with HRs per 20% VAF increase of 1.27 (95% CI, 1.13–1.42; ptrend <0.001) and 1.31 (95% CI, 1.16–1.48; ptrend <0.001), respectively. In summary, ddPCR detected KRAS mutations in clinical specimens of pancreatic cancer with high sensitivity irrespective of parameters potentially affecting mutation detections. KRAS VAF, but not mutation positivity, was associated with survival of pancreatic cancer patients.

Pancreatic cancer (PC) is among the most lethal malignancies due to an often delayed and difficult initial diagnosis. Therefore, the development of a novel, early stage, diagnostic PC marker in liquid biopsies is of great significance. In this study, we analyzed the differential glycomic profiling of extracellular vesicles (EVs) derived from serum (two cohorts including 117 PC patients and 98 normal controls) using lectin microarray. The glyco-candidates of PC-specific EVs were quantified using a high-sensitive exosome-counting system, ExoCounter. An absolute quantification system for altered glycan-containing EVs elevated in PC serum was established. EVs recognized by O-glycan-binding lectins ABA or ACA were identified as candidate markers by lectin microarray. Quantitative analyses using ExoCounter revealed that the ABA-or ACA-positive EVs were significantly increased in the culture of PC cell lines or in the serum of PC patients including carbohydrate antigen 19-9 negative patients with high area under curve values. The elevated numbers of EVs in PC serum returned to normal levels after pancreatectomy. Histological examination confirmed that the tumors stained with ABA/ACA. These specific EVs with O-glycans recognized by ABA/ACA are elevated in PC sera and can act as potential biomarkers in a liquid biopsy for PC patients screening.