Sweet bystander becomes a villain: Patients with pancreatic cancer often have elevated blood levels of CA19-9, a carbohydrate antigen present on many proteins. CA19-9 is thus commonly used as a biomarker for diagnosing and monitoring disease progression. In a study of mice, Engle et al. found that CA19-9 may be more than an innocent bystander that marks the presence of pancreatic disease; it may play a causal role in disease (see the Perspective by Halbrook and Crawford). Transgenic mice expressing the human enzymes that add CA19-9 to proteins developed severe pancreatitis that could be reversed by treatment with CA19-9 antibodies. When the transgenic mice also harbored a Kras oncogene, they went on to develop pancreatic cancer. These unexpected observations suggest new avenues for the treatment of pancreatic disease. Science , this issue p. 1156 ; see also p. 1132

BACKGROUND: Pancreatic adenocarcinoma (PAC) is part of several cancer predisposition syndromes; however, indications for genetic counseling/testing are not well‐defined. In the current study, the authors sought to determine mutation prevalence and characteristics that are predictive of an inherited predisposition for PAC.METHODS: A total of 175 consecutive patients with PAC who underwent clinical genetics assessment at Memorial Sloan Kettering Cancer Center between 2011 and 2014 were identified. Clinical data, family history, and germline results were evaluated.RESULTS: Among 159 patients with PAC who pursued genetic testing, 24 pathogenic mutations were identified (15.1%; 95% confidence interval, 9.5%‐20.7%), including BRCA2 (13 mutations), BRCA1 (4 mutations), p16 (2 mutations), PALB2 (1 mutation), and Lynch syndrome (4 mutations). BRCA1/BRCA2 prevalence was 13.7% in Ashkenazi Jewish (AJ) patients (95 patients) and 7.1% in non‐AJ patients (56 patients). In AJ patients with a strong, weak, or absent family history of BRCA‐associated cancers, the mutation prevalence was 16.7%, 15.8%, and 7.4%, respectively. The mean age at the time of diagnosis in all mutation carriers was 58.5 years (range, 45‐75 years) compared with 64 years (range, 27‐87 years) in those not carrying a mutation (P = .02). Although BRCA2 was the most common mutation identified, no patients with early‐onset PAC (diagnosed at age ≤ 50 years) harbored a BRCA2 mutation and the mean age at diagnosis in BRCA2 carriers was equivalent to that of individuals who were not mutation carriers (P = .34). Mutation prevalence in patients with early‐onset disease (21 patients) was 28.6%, including BRCA1 (2 mutations), p16 (2 mutations), MSH2 (1 mutation), and MLH1 (1 mutation).CONCLUSIONS: Mutations in BRCA2 account for > 50% of patients with PAC with an identified susceptibility syndrome. AJ patients were found to have high BRCA1/BRCA2 prevalence regardless of personal/family history, suggesting that ancestry alone indicates a need for genetic evaluation. With the exception of BRCA2‐associated PAC, an inherited predisposition for PAC is associated with an earlier age at PAC diagnosis, suggesting that this subset of patients may also represent a population warranting further evaluation. Cancer 2015;121:4382–8. © 2015 American Cancer Society.

Objective: Pancreatic stellate cells (PSCs) are important players in pancreatic fibrosis and are major contributors to the extracellular matrix proteins observed with the stromal response characteristic of pancreatic ductal adenocarcinoma (PDAC). Pancreatic stellate cells are also believed to secrete soluble factors that promote tumor progression; however, no comprehensive analysis of the PSC proteome in either the quiescent or the activated state has been reported. Methods: Using 2-dimensional tandem mass spectrometry and the RLT-PSC cell line, we present the first comprehensive study describing and comparing the quiescent and activated human PSC-secreted proteomes. Results: Very few proteins are secreted in the quiescent state. In stark contrast, activated PSCs secreted a vast array of proteins. Many of these proteins differed from those secreted by PDAC-derived cell lines. Proteins associated with wound healing, proliferation, apoptosis, fibrosis, and invasion were characterized. Selected proteins were verified in human tissue samples from PDAC, dysplastic pancreas, and normal pancreas using Western blot analysis and immunohistochemical staining. Conclusions: Our study represents the first comprehensive analysis of proteins secreted by PSCs. These findings lay the foundation for characterizing PSC-derived proteins involved in stroma-tumor interactions and the promotion of pancreatitis and PDAC. Abbreviations: α-SMA - alpha smooth muscle actin, ANXA2 - annexin A2, ECM - extracellular matrix, EZR - ezrin, GFAP - glial fibrillary acidic protein, GO - gene ontology, KEGG - Kyoto Encyclopedia of Genes and Genomes, LGALS3BP - galectin-3-binding protein, MMP2 - matrix metallopeptidase 2, NME1 - nonmetastatic cells 1, protein (NM23A), PCC - pancreatic cancer cell, PDAC - pancreatic ductal adenocarcinoma, PKM2 - pyruvate dehydrogenase kinase, muscle isoform, PLAU - urokinase plasminogen activator, PSC - pancreatic stellate cell, SERPINE1 - plasminogen activator inhibitor-1, SERPINI2 - serpin peptidase inhibitor, clade I (pancpin), member 2, SILAC - stable isotope labeling of amino acids in cell culture, TBST - TBS with 1% Tween 20, TGFBI - transforming growth factor, β-induced, 68 kd, UCHL1 - ubiquitin carboxyl-terminal esterase L1

Purpose: Notch signaling dysregulation is implicated in the development of pancreatic adenocarcinoma (PDAC). Tarextumab is a fully human IgG2 antibody that inhibits Notch2/3 receptors. Patients and Methods: Aphase 2, randomized, placebo‐controlled, multicenter trial evaluated the activity of tarextumab in combination with nab‐paclitaxel and gemcitabine in patients with metastatic PDAC. Patients were stratified based on ECOG performance score and Ca 19‐9 level and randomized 1:1 to nab‐paclitaxel, gemcitabine with either tarextumab or placebo. Based on preclinical and phase Ib results suggesting a positive correlation between Notch3 gene expression and tarextumab anti‐tumor activity, patients were also divided into subgroups of low, intermediate, and high Notch3 gene expression. Primary endpoint was overall survival (OS) in all and in patients with the three Notch3 gene expression subgroups (≥25th, ≥50% and ≥75% percentiles); secondary end points included progression‐free survival (PFS), 12‐month OS, overall response rate (ORR), and safety and biomarker investigation. Results: Median OS was 6.4 months in the tarextumab group vs 7.9 months in the placebo group (HR = 1.34 [95% CI = 0.95, 1.89], P  = .0985). No difference observed in OS in the Notch3 gene expression subgroups. PFS in the tarextumab‐treated group (3.7 months) was significantly shorter compared with the placebo group (5.5 months) (hazard ratio was 1.43 [95% CI = 1.01, 2.01]; P  = .04). Grade 3 diarrhea and thrombocytopenia were more common in the tarextumab group. Conclusions: The addition of tarextumab to nab‐paclitaxel and gemcitabine did not improve OS, PFS, or ORR in first‐line metastatic PDAC, and PFS was specifically statistically worse in the tarextumab‐treated patients. Clinical trial registry no: NCT01647828.

Effective treatment options for advanced pancreatic cancer are finite. NAPOLI-1, a phase III randomized trial, demonstrated the efficacy of nanoliposomal irinotecan with fluorouracil/leucovorin (nal-IRI + 5-FU/LV) for the treatment of advanced pancreatic cancer following progression on gemcitabine-based chemotherapy. There are limited additional data on the safety and efficacy of nal-IRI + 5-FU/LV following FDA approval in October 2015. We examined the post-approval safety and effectiveness of nal-IRI + 5-FU/LV in advanced pancreatic cancer patients receiving treatment at Memorial Sloan Kettering Cancer Center. A retrospective chart review was conducted of all patients beginning treatment with nal-IRI + 5-FU/LV from October 2015 through June 2017. Using the electronic medical record and institutional database, information was extracted pertaining to demographics, performance status (ECOG), prior therapies, dose, duration of treatment, adverse events, progression free survival (PFS), overall survival (OS) and treatment response. Fifty six patients were identified. Median progression free survival (PFS) was 2.9 months and median overall survival (OS) was 5.3 months. Patients with prior disease progression on irinotecan experienced PFS and OS of 2.2 and 3.9 mo, respectively. Patients without prior irinotecan exposure experienced significantly longer PFS (4.8 mo, p = 0.02) and OS (7.7 mo, p = 0.002), as did patients who received prior irinotecan without disease progression (PFS, 5.7 mo, p = 0.04; OS, 9.0 mo, p = .04). Progression on prior irinotecan was associated with greater lines of prior advanced disease chemotherapy (2 vs 1). Dose reductions (DR) were most frequently due to fatigue (42%) and diarrhea (37%), but were not associated with worse outcomes. In fact, patients with ≥1 DR experienced longer PFS (5.4 v 2.6 mo, p = 0.035). Sequential therapy with nab-paclitaxel + gemcitabine (nab-P + Gem) followed by nal-IRI + 5-FU/LV (n = 25) resulted in OS of 23.0 mo. Mutations in TP53 were associated with shorter PFS. These data support the safety and efficacy of nal-IRI + 5-FU/LV, reinforcing results of NAPOLI-1. Patients without disease progression on prior irinotecan fared significantly better than patients with progression, when treated with nal-IRI + 5-FU/LV. Sequential therapy with nab-P + Gem followed by nal-IRI + 5-FU/LV demonstrates encouraging median OS. These findings provide guidance for patients most likely to benefit from nal-IRI + 5-FU/LV.