Human PACC. The antitumor activities of multiple drugs (5FU, irinotecan, oxaliplatin, gemcitabine, bevacizumab, erlotinib, doxorubicin and imatinib) were tested. Tumor size was measured over 74 days or until they reached an endpoint volume of 800 mm3. Tests to measure serum lipase levels and histological analyses of tumor tissues were also conducted to assess PACC progression and redifferentiation. Results: The model presented here expresses the same IHC markers found in human PACC. In the chemotherapy study, oxaliplatin produced a prolonged durable growth response associated with increased apoptosis, decreased serum lipase levels and increased healthy acinar cells. Bevacizumab also produced a significant growth response, but the effect was not prolonged as demonstrated by oxaliplatin treatment. The other chemotherapies had moderate to little effect, particularly after treatment ceased. Mutations in DNA repair genes are common in PACC and increase tumor susceptibility to oxaliplatin. To explore this we performed IHC and found no PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/15501003 nuclear expression of BRCA2 in our model, indicating a mutation affecting nuclear localization. Gene sequencing confirms BRCA2 has a homozygous gene deletion on Exon 10, which frequently causes a protein truncation. Conclusions: In summary, we report the development and characterization of the first and only preclinical PACC PDTX model. Here we show sustained antitumor activity of single agent oxaliplatin, a compound that is more effec tive in tumors that harbor mutations in DNA repair genes. Our data shows that BRCA2 is mutated in our PACC model, which could contribute to the oxaliplatin sensitivity observed. Further studies on this rare PACC model can serve to elucidate other novel therapies, biomarkers, and molecular mechanisms of signaling and drug resistance.*Correspondence: Hall.Jason@mayo.edu Jason C. Hall and Laura A. Marlow contributed equally to this work 1 Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, 4500 San Pablo Road S., Jacksonville, FL 32224, USA Full list of author information is available at the end of the article?2016 Hall et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/ zero/1.0/) applies to the data made available in this article, unless otherwise stated.Hall et al. J Transl Med (2016) 14:Page 2 ofKeywords: Oxaliplatin, Patient derived tumor xenograft, Tumor, Pancreatic acinar cell carcinoma, Chemotherapy, Individualized medicine, Precision medicine, BRCABackground Pancreatic acinar cell carcinoma (PACC) is a rare, frequently lethal disease, accounting for less than 1 Mevastatin of all pancreatic neoplasms tumors [1?]. A retrospective series of 672 patients with PACC reported a 47 months median survival [5]. A review of patients seen at Memorial Sloan Kettering from 1981 to 2001 found that the median survival of patients with metastasis was 14 months as compared to 38 months in the absence of metastasis [1]. A follow up retrospective study reviewing patients seen from 2000 to 2011 found a median survival of 57 months for patients wi.