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Oncogenic gene fusions drive many human cancers, but tools to more quickly unravel their functional contributions are needed. Here we describe methodology permitting fusion gene construction for functional evaluation. Using this strategy, we engineered the known fusion oncogenes, BCR-ABL1, EML4-ALK, and ETV6-NTRK3, as well as 20 previously uncharacterized fusion genes identified in The Cancer Genome Atlas datasets. In addition to confirming oncogenic activity of the known fusion oncogenes engineered by our construction strategy, we validated five novel fusion genes involving MET, NTRK2, and BRAF kinases that exhibited potent transforming activity and conferred sensitivity to FDA-approved kinase inhibitors. Our fusion construction strategy also enabled domain-function studies of BRAF fusion genes. Our results confirmed other reports that the transforming activity of BRAF fusions results from truncation-mediated loss of inhibitory domains within the N-terminus of the BRAF protein. BRAF mutations residing within this inhibitory region may provide a means for BRAF activation in cancer, therefore we leveraged the modular design of our fusion gene construction methodology to screen N-terminal domain mutations discovered in tumors that are wild-type at the BRAF mutation hotspot, V600. We identified an oncogenic mutation, F247L, whose expression robustly activated the MAPK pathway and sensitized cells to BRAF and MEK inhibitors. When applied broadly, these tools will facilitate rapid fusion gene construction for subsequent functional characterization and translation into personalized treatment strategies. Cancer Res; 77(13); 3502–12. ©2017 AACR.

Fusion expression detection by PCR (S1); MET fusion expression and signaling activation by immunoblot and N-terminal partner control assay (S2); NTRK2 fusion expression and signaling activation by immunoblot and N-terminal partner control assay (S3); Expression of BRAF fusion N-terminal partner controls and BRAF structure-function studies by immunoblot and qPCR (S4)

Fusion genes and their sequences from TCGA (S1-2); Primers for fusion PCR (S3); BRAF mutants and mutagenesis primers (S4); (q)PCR primers for expression detection (S5); Fusion gene construction efficiency and success rate (S6)

BACKGROUND: Multiple neoadjuvant therapy protocols have been proposed in the treatment of pancreatic adenocarcinoma, including chemotherapy (CT), chemoradiation (CRT), and total neoadjuvant therapy (TNT), defined as a CT plus CRT. A pathologic complete response (pCR) can be achieved in a minority of cases. We hypothesize that TNT is more likely to confer pCR than other neoadjuvant therapies, which may improve overall survival (OS). METHODS: A retrospective review of the National Cancer Database (NCDB) from 2006-2016 was performed, identifying patients who underwent any neoadjuvant therapy followed by definitive pancreatic resection for locally advanced or borderline resectable pancreatic adenocarcinoma. A pathologic complete response was defined as down-staging from any clinical stage to pathologic stage 0. RESULTS: A total of 5,402 patients who received neoadjuvant therapy followed by resection were identified. 177 patients (3.3%) achieved a pCR. Of the patients who achieved a pCR, 57 received CT, 41 CRT and 79 received TNT. On multivariate analysis, TNT was more likely to confer a pCR than CRT (OR 1.67, CI 1.13-2.46, p=0.0103) or CT (OR 2.61, CI 1.83-3.71, p

Early drain removal when postoperative day (POD) one drain fluid amylase (DFA) was ≤5000 U/L reduced complications in a previous randomized controlled trial. We hypothesized that most surgeons continue to remove drains late and this is associated with inferior outcomes.We assessed the practice of surgeons in a prospectively maintained pancreas surgery registry to determine the association between timing of drain removal with demographics, comorbidities, and complications. We selected patients with POD1 DFA ≤5000 U/L and excluded those without drains, and subjects without data on POD1 DFA or timing of drain removal. Early drain removal was defined as ≤ POD5.Two hundred and forty four patients met inclusion criteria. Only 90 (37%) had drains removed early. Estimated blood loss was greater in the late removal group (190 mL versus 100 mL, P = 0.005) and pathological findings associated with soft gland texture were more frequent (97 [63%] versus 35 [39%], P 0.0001). Patients in the late drain removal group had more complications (84 [55%] versus 30 [33%], P = 0.001) including pancreatic fistula (55 [36%] versus 4 [4%], P 0.0001), delayed gastric emptying (27 [18%] versus 3 [3%], P = 0.002), and longer length of stay (7 d versus 5 d, P 0.0001). In subset analysis for procedure type, complications and pancreatic fistula remained significant for both pancreatoduodenectomy and distal pancreatectomy.Despite level one data suggesting improved outcomes with early removal when POD1 DFA is ≤ 5000 U/L, experienced pancreas surgeons more frequently removed drains late. This practice was associated with known risk factors (estimated blood loss, soft pancreas) and may be associated with inferior outcomes suggesting potential for improvement.

Background Identification of incidental pancreatic lesions is increasing because of advancements in imaging. Diagnosis remains a challenge for clinicians, with intrapancreatic accessory spleens (IPAS) posing a unique dilemma. IPAS are frequently resected because of inability to exclude alternate diagnoses, subjecting patients to unnecessary risk. The purpose of this study was to examine our institutional experience with IPAS and develop a multidisciplinary algorithm to improve preoperative diagnosis. Materials and methods Patients who underwent a distal pancreatectomy at a single institution from 2005 to 2018 were identified from a prospectively maintained database. Examination of final pathology for a diagnosis of IPAS yielded the final cohort. Demographics, preoperative workup, and operative course were reviewed and analyzed. A diagnostic algorithm was composed based on the consensus of a panel of expert pancreatic surgeons, a radiologist, and a pathologist. Results Ten patients of 303 patients who underwent a distal pancreatectomy were identified with a final pathology of IPAS. The average age was 54 y, 80% were white, and 60% were male. Lesions ranged in size from 7 mm to 5.1 cm in largest diameter (mean 2.2 cm). Lesions were described as round, well-marginated, and enhancing masses within the pancreatic tail. Preoperative workup was variable in terms of imaging and laboratory testing. Diagnostic workups were examined and combined with multidisciplinary input to create a diagnostic algorithm. Conclusions Incidental pancreatic lesions like IPAS remain a diagnostic challenge for clinicians. Employing a diagnostic algorithm as proposed may aid in the distinction of malignant and premalignant pathology and prevent unwarranted pancreatic resections.

Addition of en bloc segmental venous reconstruction (VR) to pancreaticoduodenectomy (PD) for venous involvement of pancreatic tumors increases the complexity of the operation and may increase complications. The long-term mesenteric venous patency rate and oncologic outcome has not been well defined.Our prospective database was reviewed to assess 90-day postoperative outcomes for patients who underwent PD or PD + VR (September 2004-June 2016). Two independent observers reviewed CT scans to determine long-term vein patency. In patients with pancreatic ductal adenocarcinoma, the impact of VR on 5-year overall survival was assessed using multivariate Cox proportional hazards regression. Student's t-test was used to evaluate continuous variables and the chi-square test for categorical variables.Three hundred ninety-three patients underwent PD (51 PD + VR). Patients undergoing PD + VR had longer operations (561 ± 119 versus 433 ± 89 min, P 0.00001) and greater blood loss (768 ± 812 versus 327 ± 423 cc, P 0.00001). There was no difference in 90-day mortality, overall postoperative complication rates, complication severity grades, reoperation, readmission, or length of stay. 26.7% experienced venous thrombosis. Most thromboses occurred in the first year after surgery, but we also observed late thrombosis in 1 patient after 89-month follow-up. Among 135 patients with pancreatic ductal adenocarcinoma, survival was significantly longer in the PD-alone group (31.3 months [95% confidence interval: 22.9-40.0] versus 17.0 [95% confidence interval: 13.0-19.1], pPD + VR does not increase short-term morbidity, but venous thrombosis is frequent and can occur long after surgery. Survival is inferior when VR is required especially in the absence of neoadjuvant chemotherapy.

BACKGROUND: Although used as criterion for early drain removal, postoperative day (POD) 1 drain fluid amylase (DFA) ≤ 5000 U/L has low negative predictive value for clinically relevant postoperative pancreatic fistula (CR-POPF). It was hypothesized that POD3 DFA ≤ 350 could provide further information to guide early drain removal. METHODS: Data from a pancreas surgery consortium database for pancreatoduodenectomy and distal pancreatectomy patients were analyzed retrospectively. Those patients without drains or POD 1 and 3 DFA data were excluded. Patients with POD1 DFA ≤ 5000 were divided into groups based on POD3 DFA: Group A (≤ 350) and Group B (> 350). Operative characteristics and 60-day outcomes were compared using chi-square test. RESULTS: Among 687 patients in the database, all data were available for 380. Fifty-five (14.5%) had a POD1 DFA > 5000. Among 325 with POD1 DFA ≤ 5000, 254 (78.2%) were in Group A and 71 (21.8%) in Group B. Complications (35 (49.3%) vs 87 (34.4%); p = 0.021) and CR-POPF (13 (18.3%) vs 10 (3.9%); p < 0.001) were more frequent in Group B. CONCLUSIONS: In patients with POD1 DFA ≤ 5000, POD3 DFA ≤ 350 may be a practical test to guide safe early drain removal. Further prospective testing may be useful.

Many pancreatic surgeons continue to use intraperitoneal drains, but others have limited or avoided their use, believing this improves outcomes. We conducted a systematic review and meta-analysis of the literature assessing outcomes in pancreatectomy without drains, selective drainage, and early drain removal. We searched PubMed, Embase, and the Cochrane Library databases and conducted a systematic review of randomized and nonrandomized studies comparing routine intra-abdominal drainage versus no drainage, selective drain use, and early versus late drain removal after pancreatectomy, with major complications as the primary outcome. A meta-analysis of the literature assessing routine use of drains was conducted using the random-effects model. A total of 461 articles met search criteria from PubMed (168 articles), Embase (263 articles), and the Cochrane Library (30 articles). After case reports and articles without primary data on complications were excluded, 14 studies were identified for systematic review. Definitive evidence-based recommendations cannot be made regarding the management of drains following pancreatectomy because of limitations in the available literature. Based on available evidence, the most conservative approach, pending further data, is routine placement of a drain and early removal unless the patient's clinical course or drain fluid amylase concentration suggests a developing fistula.

Background With advances in cross-sectional imaging, pancreatic cysts are more frequently diagnosed and have become a common indication for pancreatectomy. The impact of pancreatectomy in these patients is important. The purpose of this study was to assess short-term outcomes, long-term nutritional status, quality of life (QOL), and pancreas function after pancreatectomy for cystic neoplasms. Materials and methods At a single institution, patients at least 3 y post-pancreatectomy for benign cystic neoplasms were identified. Using a validated questionnaire, short-term outcomes, long-term outcomes including endocrine and exocrine insufficiency, long-term nutritional status, and preoperative and postoperative QOL were compared based on operation and indication for resection. Results Among 102 eligible patients, 70 had valid contact information and 51 (72.9%) agreed to participate. Median follow-up was 6 (4-8) y. Patients undergoing pancreatoduodenectomy for benign cysts had higher morbidity than a similar cohort resected for pancreatic adenocarcinoma (patients with at least 1 ≥ grade 2 complication [49.0% versus 31.6%, P = 0.038]). After long-term follow-up, pancreatectomy did not significantly affect perceived QOL. Half of patients had mild-moderate or severe malnourishment, but pancreatic enzyme replacement was reported by only 4 (7.8%) patients. New-onset diabetes was present in 15 (29.4%) patients with median time-to-diagnosis of 6 (1-12) mo after resection. Conclusions Pancreatectomy for benign cysts did not negatively impact patients' perceived QOL. However, after long-term follow-up, malnutrition and pancreatic insufficiency occurred in a significant percentage and may be greater than previously estimated. Consideration of short- and long-term outcomes should factor into preoperative counseling, especially in cysts with minimal risk of progression to malignancy.

The objective of this study was to test the hypothesis that distal pancreatectomy (DP) without intraperitoneal drainage does not affect the frequency of grade 2 or higher grade complications.The use of routine intraperitoneal drains during DP is controversial. Prior to this study, no prospective trial focusing on DP without intraperitoneal drainage has been reported.Patients undergoing DP for all causes at 14 high-volume pancreas centers were preoperatively randomized to placement of a drain or no drain. Complications and their severity were tracked for 60 days and mortality for 90 days. The study was powered to detect a 15% positive or negative difference in the rate of grade 2 or higher grade complications. All data were collected prospectively and source documents were reviewed at the coordinating center to confirm completeness and accuracy.A total of 344 patients underwent DP with (N = 174) and without (N = 170) the use of intraperitoneal drainage. There were no differences between cohorts in demographics, comorbidities, pathology, pancreatic duct size, pancreas texture, or operative technique. There was no difference in the rate of grade 2 or higher grade complications (44% vs. 42%, P = 0.80). There was no difference in clinically relevant postoperative pancreatic fistula (18% vs 12%, P = 0.11) or mortality (0% vs 1%, P = 0.24). DP without routine intraperitoneal drainage was associated with a higher incidence of intra-abdominal fluid collection (9% vs 22%, P = 0.0004). There was no difference in the frequency of postoperative imaging, percutaneous drain placement, reoperation, readmission, or quality of life scores.This prospective randomized multicenter trial provides evidence that clinical outcomes are comparable in DP with or without intraperitoneal drainage.

Oncogenic gene fusions drive many human cancers, but tools to more quickly unravel their functional contributions are needed. Here we describe methodology permitting fusion gene construction for functional evaluation. Using this strategy, we engineered the known fusion oncogenes, BCR-ABL1, EML4-ALK, and ETV6-NTRK3, as well as 20 previously uncharacterized fusion genes identified in The Cancer Genome Atlas datasets. In addition to confirming oncogenic activity of the known fusion oncogenes engineered by our construction strategy, we validated five novel fusion genes involving MET, NTRK2, and BRAF kinases that exhibited potent transforming activity and conferred sensitivity to FDA-approved kinase inhibitors. Our fusion construction strategy also enabled domain-function studies of BRAF fusion genes. Our results confirmed other reports that the transforming activity of BRAF fusions results from truncation-mediated loss of inhibitory domains within the N-terminus of the BRAF protein. BRAF mutations residing within this inhibitory region may provide a means for BRAF activation in cancer, therefore we leveraged the modular design of our fusion gene construction methodology to screen N-terminal domain mutations discovered in tumors that are wild-type at the BRAF mutation hotspot, V600. We identified an oncogenic mutation, F247L, whose expression robustly activated the MAPK pathway and sensitized cells to BRAF and MEK inhibitors. When applied broadly, these tools will facilitate rapid fusion gene construction for subsequent functional characterization and translation into personalized treatment strategies. Cancer Res; 77(13); 3502–12. ©2017 AACR.

Pancreatic cysts include a variety of benign, premalignant, and malignant lesions. Endometrial cysts in the pancreas are exceedingly rare lesions that are difficult to diagnose pre-operatively. This report describes the findings in a 43-year-old patient with a recent episode of acute pancreatitis who presented with a large cyst in the tail of the pancreas. Imaging demonstrated a loculated pancreatic cyst, and cyst fluid aspiration revealed an elevated amylase and carcinoembryonic antigen. The patient experienced an interval worsening of abdominal pain, fatigue, diarrhea, and a 15-pound weight loss 3 mo after the initial episode of pancreatitis. With concern for a possible pre-malignant lesion, the patient underwent a laparoscopic distal pancreatectomy with splenectomy, which revealed a 16 cm × 12 cm × 4 cm lesion. Final histopathology was consistent with an intra-pancreatic endometrial cyst. Here we discuss the overlapping imaging and laboratory features of pancreatic endometrial cysts and mucinous cystic neoplasms of the pancreas.