P 169 PANCREATIC MIXED ACINAR CELL CARCINOMA: GENOMIC ANALYSIS AND CHARACTERIZATION OF A PATIENT-DERIVED ORGANOID CULTURE B. A. Rheinheimer, T. S. Riall, R. L. Heimark and T. Jie * *Corresponding author. Tun Jie, University of Arizona, United States Background: Mixed acinar cell carcinomas occur in <2% of all pancreatic cancers and express markers for both neuroendocrine and acinar cell differentiation. The clinical prognosis and molecular characterization of mixed acinar cell carcinomas are not well understood; therefore, we initiated a study to link genomic and transcriptomic anal- ysis of mixed acinar cell carcinomas with pathogenesis. This case study represents a mixed acinar cell carcinoma in the pancreatic head that was surgically resected by a pancreaticoduedenectomy. The tumor was clinically staged pT3N1MX with a KI-67 labeling index of 5%. Methods: The macrodissected tumor specimen was subdivided for genomic analysis and explantation in orga- noid culture. After digestion with collagenase, the tissue was washed and plated in 50% Matrigel in Human Com- plete Organoid media. The cultures were subsequently established and characterized by immunolabeling for neuroendocrine and acinar lineage markers and by quanti- tative RT-PCR. After 3 passages of the organoid cultures, the cultures were then placed in 2D culture on 2% Matrigel coated dishes. DNA was isolated and whole exome sequencing was performed using the Nextera Rapid Cap- ture Exome Kit by Illumina on an Illumina HiSeq 2000/ 2500. The following criteria were used to define genetic variants: bidirectional, non-synonymous, clean mapping in IGV,  15X coverage, and an alternate allele frequency of 0.3  x  0.7. Results: The primary tumor showed a mixed population of cell types on H&E. Tumor cells were positive for intra- cytoplasmic trypsin staining indicative of acinar differen- tiation. Tumor cells were also positive for the neuroendocrine markers synaptophysin and chromogranin A suggesting a population of cells that show both acinar and endocrine histology. The tumor was negative for gastrin, insulin, somatostatin, and glucagon. Cell growth in the initial organoid culture resulted in a mixed culture with 3D acinar structures and a second population of cells with multiple protrusions that invaded into the Matrigel. Whole exome sequencing of the dissected primary tumor showed mutations in several genes including MEN1, histone modification genes, and DNA repair pathway genes. Conclusion: Our approach is to combine patient-derived PanNET organoid cultures with cancer biology and mo- lecular genetic analyses to understand their clinical significance. P 170 LAPAROSCOPIC HEPATECTOMY FOR PREOPERATIVE SUSPECTED HEPATOCELLULAR CARCINOMA: PERIOPERATIVE RESULTS AT A SINGLE CENTER C. U. Marino * , D. A. Daroch, A. N. Ramírez, J. F. Guerra, J. Martínez, N. P. Jarufe and E. Briceño *Corresponding author. Carlo Marino, Pontificia Universidad Católica de Chile, United States Background: Liver resection in cirrhotic patients is asso- ciated with higher rates of morbidity and mortality. On the other hand, the laparoscopic approach for hepatocellular carcinoma (HCC) resections has been associated with better perioperative outcomes, including less blood loss, shorter length of hospital stay and reduced postoperative complications. The aim of this study is to describe the perioperative Results of laparoscopic hepatectomy for preoperative suspected HCC in our center. Methods: We performed a case series study. Between August 2006 and August 2018, all patients undergoing laparoscopic hepatectomy for preoperative suspected HCC were included. All clinical records were reviewed, regis- tering information regarding to age, gender, comorbidities and chronic liver failure status. We also registered the size of the tumor on preoperative imaging, alpha-fetoprotein (AFP) levels, type of liver resection, intraoperative red blood cells transfusions, operative time, conversion rates, postoperative complications (according to Clavien-Dindo classification) and mortality, reintervention rates, post- operative length of stay, readmissions and pathology. Descriptive statistics were used to analyze the Results. Results: A total of 20 laparoscopic liver resections (LLR) for suspected HCC were performed in the study period. The median age of the group was 68 years (19e82) and 70% (N = 14) of the patients were men. 60% (N = 12) and 30% (N = 6) had hypertension and type 2 diabetes, respectively. 80% (N = 16) had chronic liver failure and, among them, 87,5% (N = 14) were Child-Pugh A classification. The median size of the tumor, measured in preoperative imag- ing, was 3,3 cm (1e11) and the median of AFP was 4,55 ng/mL (0,7-26,9). 50% (N = 10) of the patients underwent non-anatomic liver resections, 15% (N = 3) right HPB 2019, 21 (S1), S98eS188 ePoster abstracts S147