James Abbruzzese

Because the peroxisome proliferator-activated receptor (PPAR) signaling pathway is involved in development and progression of pancreatic cancer, we investigated associations between genetic variants of the PPAR pathway genes and pancreatic cancer risk by using three published genome-wide association study datasets including 8477 cases and 6946 controls of European ancestry. Expression quantitative trait loci (eQTL) analysis was also performed for correlations between genotypes of the identified genetic variants and messenger RNA (mRNA) expression levels of their genes by using available databases of the 1000 Genomes, TCGA, and GTEx projects. In the single-locus logistic regression analysis, we identified 1141 out of 17 532 significant single-nucleotide polymorphisms (SNPs) in 112 PPAR pathway genes. Further multivariate logistic regression analysis identified three independent, potentially functional loci (rs12947620 in MED1, rs11079651 in PRKCA, and rs34367566 in PRKCB) for pancreatic cancer risk (odds ratio [OR] = 1.11, 95% confidence interval [CI], [1.06-1.17], P = 5.46 × 10-5 ; OR = 1.10, 95% CI, [1.04-1.15], P = 1.99 × 10-4 ; and OR = 1.09, 95% CI, [1.04-1.14], P = 3.16 × 10-4 , respectively) among 65 SNPs that passed multiple comparison correction by false discovery rate (< 0.2). When risk genotypes of these three SNPs were combined, carriers with 2 to 3 unfavorable genotypes (NUGs) had a higher risk of pancreatic cancer than those with 0 to 1 NUGs. The eQTL analysis showed that rs34367566 A>AG was associated with decreased expression levels of PRKCB mRNA in 373 lymphoblastoid cell lines. Our findings indicate that genetic variants of the PPAR pathway genes, particularly MED1, PRKCA, and PRKCB, may contribute to susceptibility to pancreatic cancer.

BACKGROUND: Adjuvant chemotherapy (AC) is associated with improved survival following resection of pancreatic adenocarcinoma but is frequently delayed or deferred due to perioperative complications or patient deconditioning. The aim of this study was to assess impact of delayed AC on overall survival after pancreaticoduodenectomy for pancreatic head adenocarcinoma. METHODS: Patients with stage I-III pancreatic head adenocarcinoma in the 2006-2015 National Cancer Database were grouped by timing of AC (<6-weeks, 6-12-weeks, and 12-24-weeks). Overall survival was compared using Cox proportional hazard models adjusting for patient, tumor, and hospital factors. Subgroup analyses were conducted to assess the impact of comorbidities, readmission or extended hospital stay, and receipt of single- versus multi-agent chemotherapy. RESULTS: Of 13438 patients, 4552 (33.9%) received no AC, 2112 (15.7%) received AC <6-weeks following resection, 5580 (41.5%) within 6-12 weeks, and 1194 (8.9%) within 12-24 weeks. AC was associated with improved overall survival (adjusted hazard ratio [HR] <6-weeks: 0.765, 6-12-weeks: 0.744, and 12-24-weeks: 0.736 (p < 0.001)). This survival advantage persisted for patients with comorbidities, those with postoperative complications, and in those receiving single- or multi-agent regimens. CONCLUSIONS: For patients with stage I-III pancreatic adenocarcinoma, receipt of AC is associated with improved overall survival, even if delayed up to 24-weeks.

Diabetes and perineural invasion are frequently observed in pancreatic cancer. In this study, we tested possible relations between diabetes and perineural invasion in patients with resected pancreatic cancer. We conducted a retrospective study in 544 cases of resected pancreatic adenocarcinoma seen at the University of Texas MD Anderson Cancer Center during 1996-2011. Information on tumor characteristics, diabetes history, and survival time was collected by personal interview and medical record review. Patients with diabetes before or at the time of the pancreatic cancer diagnosis were considered diabetes only. Pearson χ(2) test was used to compare categorical variables in diabetic and nondiabetic groups. Kaplan-Meier plot, log-rank test, and Cox proportional regression models were applied in survival analysis. The prevalence of diabetes and perineural invasion was 26.5% and 86.9%, respectively, in this study population. Patients with diabetes had a significantly higher prevalence of perineural invasion (92.4%) than those without diabetes (85%) (P = 0.025, χ(2) test). Diabetes was not associated with other pathological characteristics of the tumor, such as tumor size, lymphovascular invasion, tumor grade, lymph node metastasis, and resection margin status. Diabetic patients had a significantly lower frequency of abdominal pain (P = 0.01), but a slightly higher frequency of weight loss (P = 0.078) as early symptoms of their cancer. Both diabetes and perineural invasion were related to worse survival and increased risk of death after adjusting for tumor grade and margin and node status (P = 0.036 and 0.019, respectively). The observed associations of diabetes and perineural invasion as well as reduced frequency of pain as early symptom of pancreatic cancer support the hypothesis that diabetes may contribute to pancreatic progression via the mechanism of nerve damage.