Recent studies have offered ample insight into genome-wide expression patterns to define pancreatic ductal adenocarcinoma (PDAC) subtypes, although there remains a lack of knowledge regarding the underlying epigenomics of PDAC. Here we perform multi-parametric integrative analyses of chromatin immunoprecipitation-sequencing (ChIP-seq) on multiple histone modifications, RNA-sequencing (RNA-seq), and DNA methylation to define epigenomic landscapes for PDAC subtypes, which can predict their relative aggressiveness and survival. Moreover, we describe the state of promoters, enhancers, super-enhancers, euchromatic, and heterochromatic regions for each subtype. Further analyses indicate that the distinct epigenomic landscapes are regulated by different membrane-to-nucleus pathways. Inactivation of a basal-specific super-enhancer associated pathway reveals the existence of plasticity between subtypes. Thus, our study provides new insight into the epigenetic landscapes associated with the heterogeneity of PDAC, thereby increasing our mechanistic understanding of this disease, as well as offering potential new markers and therapeutic targets.

SUMMARYPreclinical models based on patient-derived xenografts have remarkable specificity in distinguishing transformed human tumor cells from non-transformed murine stromal cells computationally. We obtained 29 pancreatic ductal adenocarcinoma (PDAC) xenografts from either resectable or non-resectable patients (surgery and endoscopic ultrasound-guided fine-needle aspirate, respectively). Extensive multiomic profiling revealed two subtypes with distinct clinical outcomes. These subtypes uncovered specific alterations in DNA methylation and transcription as well as in signaling pathways involved in tumor-stromal cross-talk. The analysis of these pathways indicates therapeutic opportunities for targeting both compartments and their interactions. In particular, we show that inhibiting NPC1L1 with Ezetimibe, a clinically available drug, might be an efficient approach for treating pancreatic cancers. These findings uncover the complex and diverse interplay between PDAC tumors and the stroma and demonstrate the pivotal role of xenografts for drug discovery and relevance to PDAC.

Background Pancreatic neuroendocrine tumors (NETs) and intraductal pancreatic mucinous neoplasia (IPMN) with worrisome features are surgically managed. Endoscopic ultrasound (EUS)-guided radiofrequency ablation (RFA) has recently been developed. The safety of EUS-RFA was the primary end point of this study, its efficacy the secondary end point. Methods This was a prospective multicenter study that was planned to include 30 patients with a 1-year follow-up with either a NET < 2 cm or a pancreatic cystic neoplasm (PCN), either a branch duct IPMN with worrisome features or a mucinous cystadenoma (MCA). EUS-RFA was performed with an 18G RFA cooling needle. Results 12 patients had 14 NETs (mean size 13.1 mm, range 10 – 20 mm); 17 patients had cystic tumors (16 IPMNs, 1 MCA; mean size 28 mm, range 9 – 60 mm). Overall three adverse events occurred (10 %), two of these in the first two patients (one pancreatitis, one small-bowel perforation). After these initial patients, modifications in the protocol resulted in a decrease in complications (3.5 %), with one patient having a pancreatic ductal stenosis. Among the 14 NETs, at 1-year follow-up 12 had completely disappeared (86 % tumor resolution), with three patients having a delayed response. Among the 17 PCNs, at 12 months, there were 11 complete disappearances and one diameter that decreased by > 50 % (significant response rate 71 %). All 12 mural nodules showed complete resolution. Conclusions EUS-RFA of pancreatic NETs or PCNs is safe with a 10 % complication rate, which can be decreased by improved prophylaxis for the procedure.

Geriatric factors (MMSE and IADL) are predictive of severe toxicity or unexpected hospitalization (MMSE) in a randomized prospective phase III study in mCRC. These results suggest that cognitive function and autonomy impairment should be taken into account when choosing a regimen for chemotherapy.