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Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with limited treatment options. Recently, the poly(ADP-ribose) polymerase inhibitor (PARPi) olaparib has been approved for maintenance therapy after successful platinum-based chemotherapy in patients with germline mutations in BRCA1 and BRCA2. Approval was based on the POLO study that has shown a significant improvement in progression-free survival for patients with metastatic PDAC after at least 4 months of platinum-based chemotherapy. Hopefully, this first biomarker-directed targeted therapy for a relevant subgroup of pancreatic cancer patients is only the beginning of an era of personalized therapy for pancreatic cancer. The potential role for PARPi in improving survival in patients with pancreatic cancer containing somatic tumor mutations has yet to be established. Multiple studies investigating whether PARPi therapy might benefit a larger group of pancreatic cancer patients with homologous recombination repair deficiency and whether combinations with chemotherapy, immunotherapy, or small molecules can improve efficacy are currently underway. We here review the molecular basis for PARPi therapy in PDAC patients and recent developments in clinical studies.

Perioperative systemic treatment is standard of care for Caucasian patients with locally advanced, resectable gastric adenocarcinoma. The prognostic relevance of the microsatellite instability (MSI) status in patients undergoing neoadjuvant chemotherapy followed by resection is unclear. We analyzed the association of the MSI status with histological regression and clinical outcome in patients undergoing neoadjuvant systemic treatment. Tumor tissue from patients undergoing neoadjuvant chemotherapy followed by resection for gastric or gastroesophageal-junction adenocarcinoma was analyzed for MSI status using a mononucleotide marker panel encompassing the markers BAT25, BAT26, and CAT25. Histological regression, relapse-free survival and overall survival were calculated and correlated with MSI status. We identified the MSI-H phenotype in 9 (8.9%) out of 101 analyzed tumors. Though a poor histological response was observed in eight out of nine MSI-H patients, overall survival was significantly better for patients with MSI-H compared to MSS tumors (median overall survival not reached vs. 38.6 months, log-rank test p = 0.014). Among MSI-H patients, an unexpected long-term survival after relapse was observed. Our data indicate that the MSI-H phenotype is a favorable prognostic marker in gastric cancer patients undergoing neoadjuvant treatment. The benefit of perioperative cytotoxic treatment in patients with MSI-H gastric cancer, however, remains questionable. Future trials should stratify patients according to their MSI status, and novel treatment modalities focusing on MSI-H tumors should be considered.

The importance of polymeric transportation systems has been steadily increasing over the years. It is a useful material in numerous applications, such as packaging, oil and gas pipes, and household items. One particular aspect of polyethylene (PE) is the permeability of small molecules, such as low-molecular-weight hydrocarbons. In the present study, PE sheets were crosslinked by grafting and subsequent hydrolysis of organosilanes during a reactive extrusion process. The formation of a network structure was characterized by sol/gel analysis and by rheological measurements. It is shown that as a result of crosslinking the permeation of linear alkanes through the PE is reduced. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45374.