B-cell responses are emerging as critical regulators of cancer progression. In this study, we investigated the role of B lymphocytes in the microenvironment of human pancreatic ductal adenocarcinoma (PDAC), in a retrospective consecutive series of 104 PDAC patients and in PDAC preclinical models. Immunohistochemical analysis revealed that B cells occupy two histologically distinct compartments in human PDAC, either scatteringly infiltrating (CD20-TILs), or organized in tertiary lymphoid tissue (CD20-TLT). Only when retained within TLT, high density of B cells predicted longer survival (median survival 16.9 mo CD20-TLT vs. 10.7 mo CD20-TLT; = 0.0085). Presence of B cells within TLT associated to a germinal center (GC) immune signature, correlated with CD8-TIL infiltration, and empowered their favorable prognostic value. Immunotherapeutic vaccination of spontaneously developing PDAC (Kras-Pdx1-Cre) mice with α-enolase (ENO1) induced formation of TLT with active GCs and correlated with increased recruitment of T lymphocytes, suggesting induction of TLT as a strategy to favor mobilization of immune cells in PDAC. In contrast, in an implanted tumor model devoid of TLT, depletion of B cells with an anti-CD20 antibody reinstated an antitumor immune response. Our results highlight B cells as an essential element of the microenvironment of PDAC and identify their spatial organization as a key regulator of their antitumor function. A mindfully evaluation of B cells in human PDAC could represent a powerful prognostic tool to identify patients with distinct clinical behaviors and responses to immunotherapeutic strategies.

Overall, our data highlight TAMs as critical determinants of prognostic responsiveness to CTX and provide clinical and in vitro evidence that CTX overall directly re-educates TAMs to restrain tumour progression. These results suggest that the quantification of TAMs could be exploited to select patients more likely to respond to CTX and provide the basis for novel strategies aimed at re-educating macrophages in the context of CTX.

BackgroundThe routine use of preoperative biliary drainage before pancreaticoduodenectomy (PD) remains controversial. This observational retrospective study compared stented and non-stented patients undergoing PD to assess any differences in post-operative morbidity and mortality.MethodsA total of 180 consecutive patients who underwent PD and had intra-operative bile cultures performed between January 2010 and February 2013 were retrospectively identified. All patients received peri-operative intravenous antibiotic prophylaxis, primarily cefazolin.ResultsOverall incidence of post-operative surgical complications was 52.3 %, with no difference between stented and non-stented patients (53.4 % vs. 51.1 %; p = 0.875). However, stented patients had a significantly higher incidence of deep incisional surgical site infections (SSIs) (p = 0.038). In multivariate analysis, biliary stenting was confirmed as a risk factor for deep incisional SSIs (p = 0.044). Significant associations were also observed for cardiac disease (p = 0.010) and BMI ≥25 kg/m2 (p = 0.045). Enterococcus spp. were the most frequent bacterial isolates in bile (74.5 %) and in drain fluid (69.1 %). In antimicrobial susceptibilty testing, all Enterococci isolates were cefazolin-resistant.ConclusionGiven the increased risk of deep incisional SSIs, preoperative biliary stenting in patients underging PD should be used only in selected patients. In stented patients, an antibiotic with anti-enterococcal activity should be chosen for PD prophylaxis.

Laparoscopic distal pancreatectomy (LDP) for benign and borderline pancreatic lesions is recently becoming the treatment of choice in experienced centres. No data have been published on learning curve so far. The purpose of this study was to identify the learning curve period for performing LDP. Between March 2009 and August 2010 all patients with lesions of pancreatic body or tail were assessed for eligibility for LDP. Exclusion criteria were: major vessels contact in cancer patients, severe organ dysfunction, BMI > 35, and refusing laparoscopic approach. All laparoscopic procedures were carried out by the same surgical team with large experience in open pancreatic surgery. All patients were treated according to an early recovery after surgery protocol. Primary endpoint was conversion rate. Secondary endpoints were operative time, operative blood loss, postoperative morbidity, and length of stay (LOS). Sixty patients were assessed for eligibility. Thirty (50.0 %) patients met the exclusion criteria, while the other 30 patients underwent LDP. Spleen-preserving procedure was planned in the 17 patients with benign lesion and successfully performed in 15 (82.3 %). Overall conversion rate was 23.3 %, but it dropped significantly after the first ten patients (p = 0.01). Mean operative time progressively declined from 254 min in the first subgroup of ten patients to 206 min in the second (p = 0.09 vs. first), and 183 min in the third subgroup (p = 0.006 vs. first). No significant difference was found for operative blood loss, postoperative morbidity rate, and LOS in the different subgroups. Both conversion rate and operative time dropped after the first ten patients who underwent LDP. Strict selection criteria, high-volume hospital, and experienced team in open pancreatic surgery may have played a role in shortening the learning curve.

Background: One of the controversial issues in the diagnosis of pancreatic neuroendocrine tumours (pNETs) is the accurate prediction of their clinical behaviour. Objectives: The aim of the study was to evaluate the role of endoscopic ultrasound (EUS) biopsy in the diagnosis and grading of pNETs in a certified ENETS Center. Methods: A prospectively maintained database of EUS biopsy procedures was retrospectively reviewed to identify all consecutive patients referred to a certified ENETS Center with a suspicion of pNET between June 2014 and April 2017. The cytological and/or histological specimens were stained and the Ki-67 labeling index was evaluated. In patients undergoing surgery, the grade obtained with EUS-guided biopsy was compared with the final histological grade. The grade was evaluated according to the 2017 WHO classifications and grading. Results: The study population included 59 patients. EUS biopsy material reached an adequacy of 98.3% and was adequate for Ki-67 evaluation in 84.7% of cases. Twenty-nine patients (49.2%) underwent surgery. Of these, 25 patients had Ki-67 evaluated on EUS biopsy: the agreement between EUS biopsy grading and surgical specimen grading was 84%. Conclusion: EUS biopsy is an accurate method for the diagnosis and grading of pNETs based on the WHO 2017 Ki-67 labelling scheme.