Background: Treatment outcomes for patients with advanced pancreatic ductal adenocarcinoma (PDAC) remain dismal. There are unmet needs for understanding the biologic basis of this malignancy using novel next-generation sequencing technologies. Herein, we investigated the clinical utility of circulating tumor DNA (ctDNA) (the liquid biopsy) in this malignancy. Methods: ctDNA was analyzed in 112 patients with PDAC (54-73 genes) and tissue DNA in 66 patients (315 genes) (both clinical-grade next-generation sequencing). Number of alterations, %ctDNA, concordance between ctDNA and tissue DNA, and correlation of ctDNA results with survival were assessed. Results:The most common genes altered in ctDNA were TP53 (46% of patients, N = 51) and KRAS (44%, N = 49). Median number of characterized ctDNA alterations per patient was 1 (range, 0-6), but patients with advanced PDAC had significantly higher numbers of ctDNA alterations than those with surgically resectable disease (median, 2 versus 0.5, P = 0.04). Overall, 75% (70/94) of advanced tumors had ≥ 1 ctDNA alteration. Concordance rate between ctDNA and tissue DNA alterations was 61% for TP53 and 52% for KRAS. Concordance for KRAS alterations between ctDNA and tissue DNA from metastatic sites was significantly higher than between ctDNA and primary tumor DNA (72% vs 39%, P = 0.01). Importantly, higher levels of total %ctDNA were an independent prognostic factor for worse survival (hazard ratio, 4.35; 95% confidence interval, 1.85-10.24 [multivariate, P = 0.001]). A patient with three ctDNA alterations affecting the MEK pathway (GNAS, KRAS, and NF1) attained a response to trametinib monotherapy ongoing at 6 months.Conclusions: Our findings showed that ctDNA often harbored unique alterations some of which may be targetable and that significantly greater numbers of ctDNA alterations occur in advanced versus resectable disease. Furthermore, higher ctDNA levels were a poor prognostic factor for survival.

Gemcitabine based treatment is currently a standard first line treatment for patients with advanced pancreatic cancer, however overall survival remains poor, and few options are available for patients that fail gemcitabine based therapy. To identify potential molecular targets in gemcitabine refractory pancreatic cancer, we developed a series of gemcitabine resistant (GR) cell lines. Initial drug exposure selected for an early resistant phenotype that was independent of drug metabolic pathways. Prolonged drug selection pressure after 16 weeks, led to an induction of cytidine deaminase (CDA) and enhanced drug detoxification. Cross resistance profiles demonstrate approximately 100-fold cross resistance to the pyrimidine nucleoside cytarabine, but no resistance to the same in class agents, azacytidine and decitabine. GR cell lines demonstrated a dose dependent collateral hypersensitivity to class I and II histone deacetylase (HDAC) inhibitors and decreased expression of 3 different global heterochromatin marks, as detected by H4K20me3, H3K9me3 and H3K27me3. Cell morphology of the drug resistant cell lines demonstrated a fibroblastic type appearance with loss of cell-cell junctions and an altered microarray expression pattern, using Gene Ontology (GO) annotation, consistent with progression to an invasive phenotype. Of particular note, the gemcitabine resistant cell lines displayed up to a 15 fold increase in invasive potential that directly correlates with the level of gemcitabine resistance. These findings suggest a mechanistic relationship between chemoresistance and metastatic potential in pancreatic carcinoma and provide evidence for molecular pathways that may be exploited to develop therapeutic strategies for refractory pancreatic cancer.

Intrabiliary metastasis from colorectal carcinoma (CRC) growing within or invading bile ducts is not a very common pattern. However, accurate diagnosis of metastatic lesions is very important for selection of adjuvant therapy and prognosis. We report a case of 71-year-old male who developed painless jaundice due to hepatobiliary obstruction. MRI demonstrated 1.4 cm intraductal mass at hepatic hilum with severe intrahepatic ductal dilation, consistent with cholangiocarcinoma. ERCP (endoscopic retrograde cholangiopancreatography) showed intraductal segmental biliary stricture. Biopsy from the lesion showed adenocarcinoma favoring primary cholangiocarcinoma due to the papillary morphology and location of the mass. His past history was significant for rectosigmoid carcinoma (pT1N0) ten years ago and liver resection for metastatic CRC four years ago. He subsequently underwent central hepatectomy with resection of common bile duct. Grossly, there was a 1.2 cm intraductal mass at the bifurcation of bile ducts with multiple nodules in liver parenchyma. Microscopic examination revealed intraductal carcinoma with papillary architecture colonizing bile duct epithelium with resultant dilation and tortuosity. Occasional liver parenchymal nodules show classical metastatic pattern resembling CRC. Because of two distinct morphologic patterns and patient's past history, immunostains were performed. CK7 stained uninvolved bile duct epithelium with no staining in intrabiliary metastatic growth. CK20 and CDX2 were positive, thus confirming intrabiliary growth as metastatic growth from CRC. In summary, findings from our case indicate that intrabiliary growth of metastatic CRC can easily be overlooked with major duct involvement. Pathologic evaluation with use of immunohistochemical stains is very important to achieve correct diagnosis.

Enteric duplication cysts are rare congenital malformations that can occur at any point along the digestive tract, most commonly the small bowel. They are characterized by the presence of an outer layer of smooth muscle and an inner lining of mucosa that may resemble any portion of the digestive tract. Less commonly, cases have been reported that also contain mucosal components of nonintestinal origin. This entity is typically diagnosed in young children, but occasionally presents in adolescence and young adulthood. We present a rare case of a 21-year-old male who presented with nonspecific symptoms of abdominal discomfort and weight loss and was later found to have a 9 cm nonenhancing mass in the distal ileum on CT imaging. Laparoscopic dissection of the mass revealed a cystic lesion lined mainly by pseudostratified ciliated columnar respiratory-type epithelium, with patchy areas of squamous epithelium as well as villous columnar epithelium resembling small bowel. The unique histology and advanced patient age make this case a unique presentation of what is already a rare pathological entity.

In aggregate, overutilization exceeded 20%. At the focus hospital, approximately one-quarter of patients receiving transfusions had a Hb concentration greater than 10.0 g/dL at discharge. Transfused patients' discharge Hb concentration represents an effective indicator for retrospective monitoring of transfusion appropriateness. In light of the large number of patients receiving even number transfusions, reviewing Hb levels after transfusion of each RBC unit could reduce unnecessary transfusions. Retrospective review of discharge Hb data focuses providers on transfusion outcomes and affords an educational opportunity for blood utilization management.