Background. The therapeutic resistance of pancreatic ductal adenocarcinoma (PDAC) is partly ascribed to ineffective delivery of chemotherapy to cancer cells. We hypothesized that physical properties at vascular, extracellular, and cellular scales influence delivery of and response to gemcitabine-based therapy. Methods. We developed a method to measure mass transport properties during routine contrast-enhanced CT scans of individual human PDAC tumors. Additionally, we evaluated gemcitabine infusion during PDAC resection in 12 patients, measuring gemcitabine incorporation into tumor DNA and correlating its uptake with human equilibrative nucleoside transporter (hENT1) levels, stromal reaction, and CT-derived mass transport properties. We also studied associations between CT-derived transport properties and clinical outcomes in patients who received preoperative gemcitabine-based chemoradiotherapy for resectable PDAC. Results. Transport modeling of 176 CT scans illustrated striking differences in transport properties between normal pancreas and tumor, with a wide array of enhancement profiles. Reflecting the interpatient differences in contrast enhancement, resected tumors exhibited dramatic differences in gemcitabine DNA incorporation, despite similar intravascular pharmacokinetics. Gemcitabine incorporation into tumor DNA was inversely related to CT-derived transport parameters and PDAC stromal score, after accounting for hENT1 levels. Moreover, stromal score directly correlated with CT-derived parameters. Among 110 patients who received preoperative gemcitabine-based chemoradiotherapy, CT-derived parameters correlated with pathological response and survival. Conclusion. Gemcitabine incorporation into tumor DNA is highly variable and correlates with multiscale transport properties that can be derived from routine CT scans. Furthermore, pretherapy CT-derived properties correlate with clinically relevant endpoints. Trial registration. Clinicaltrials.gov NCT01276613. Funding. Lustgarten Foundation (989161), Department of Defense (W81XWH-09-1-0212), NIH (U54CA151668, KCA088084).

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the United States yet data are scant regarding host factors influencing pancreatic carcinogenesis. Increasing evidence support the role of the host microbiota in carcinogenesis but its role in PDAC is not well established. Herein, we report that antibiotic-mediated microbial depletion of Kras^G12D/PTEN^lox/+ mice showed a decreased proportion of poorly differentiated tumors compared to microbiota-intact Kras^G12D/PTEN^lox/+ mice. Subsequent 16S rRNA PCR showed that ~50% of Kras^G12D/PTEN^lox/+ mice with PDAC harbored intrapancreatic bacteria. To determine if a similar observation in humans correlates with presence of PDAC, benign and malignant human pancreatic surgical specimens demonstrated a microbiota by 16S bacterial sequencing and culture confirmation. However, the microbial composition did not differentiate PDAC from non-PDAC tissue. Furthermore, murine pancreas did not naturally acquire a pancreatic microbiota, as germ-free mice transferred to specific pathogen-free housing failed to acquire intrapancreatic bacteria over time, which was not augmented by a murine model of colitis. Finally, antibiotic-mediated microbial depletion of Nod-SCID mice, compared to microbiota-intact, showed increased time to PDAC xenograft formation, smaller tumors, and attenuated growth. Interestingly, both xenograft cohorts were devoid of intratumoral bacteria by 16S rRNA PCR, suggesting that intrapancreatic/intratumoral microbiota is not the sole driver of PDAC acceleration. Xenografts from microbiota-intact mice demonstrated innate immune suppression by immunohistochemistry and differential regulation of oncogenic pathways as determined by RNA sequencing. Our work supports a long-distance role of the intestinal microbiota on PDAC progression and opens new research avenues regarding pancreatic carcinogenesis.

An analysis of the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplant Registry data shows that the greater the viral load at the time of transplantation, the more rapidly clinically evident posttransplantation hepatitis C virus (HCV) disease recurs. These data suggest that aggressive pretransplantation treatment of HCV might delay recurrent posttransplantation HCV disease and enhance posttransplantation survival. We have taken an aggressive approach to treating HCV infection pretransplantation with the use of high-dose (5 MU) daily interferon α_2b in an effort to clear the virus before transplantation. A total of 27 patients with HCV-induced cirrhosis were seen and underwent transplantation at Loyola University Medical Center (Maywood, IL) between February 1997 and December 2001. There were 22 men and five women, with a mean age of 56 ± 2 years. The majority had genotype 1 disease (67%). Of the 27 patients, 7 had a baseline platelet count <50,000/mm³ and were excluded from interferon therapy. The remaining 20 were treated for a mean of 14 ± 2.5 (range, 0.5 to 33.5) months before orthotopic liver transplantation (OLT). Twelve (60%) responded to the therapy with serologic clearance of HCV before OLT. The mean time from initiation of therapy to the first negative qualitative polymerase chain reaction was 4.5 ± 1.5 (range, 0.5 to 12) months. Four of the 12 patients in whom the virus cleared did not have evidence of HCV recurrence after OLT, representing 20% of those treated and 33% of those who had HCV clearance before OLT. The duration of post-OLT freedom from HCV infection in these individuals has been 33.6 ± 11.3 (range, 0 to 47.4) months. These data suggest that with careful supervision, cirrhotic patients can tolerate high-dose interferon. In addition, a viral clearance can be achieved in a significant number of cirrhotic patients with high-dose interferon. One third of patients, in whom the HCV cleared before OLT, did not have evidence of disease recurrence after OLT. It is thus anticipated that with early and aggressive pre-OLT HCV therapy, possibly with the use of pegylated interferon, even better results may be obtained.