Most patients diagnosed with resected pancreatic adenocarcinoma (PDAC) survive less than 5 years, but a minor subset survives longer. Here, we dissect the role of the tumor microbiota and the immune system in influencing long-term survival. Using 16S rRNA gene sequencing, we analyzed the tumor microbiome composition in PDAC patients with short-term survival (STS) and long-term survival (LTS). We found higher alpha-diversity in the tumor microbiome of LTS patients and identified an intra-tumoral microbiome signature (Pseudoxanthomonas-Streptomyces-Saccharopolyspora-Bacillus clausii) highly predictive of long-term survivorship in both discovery and validation cohorts. Through human-into-mice fecal microbiota transplantation (FMT) experiments from STS, LTS, or control donors, we were able to differentially modulate the tumor microbiome and affect tumor growth as well as tumor immune infiltration. Our study demonstrates that PDAC microbiome composition, which cross-talks to the gut microbiome, influences the host immune response and natural history of the disease.

Purpose Enhancer of zeste homolog 2 (EZH2) promotes carcinogenesis by epigenetically silencing tumor suppressor genes. We studied EZH2 expression by immunohistochemistry in a large series of non-small cell lung carcinomas (NSCLC) in association with tumor characteristics and patient outcomes. Experimental Design EZH2 immunohistochemistry expression was analyzed in 265 normal and premalignant bronchial epithelia, 541 primary NSCLCs [221 squamous cell carcinomas (SCCs) and 320 adenocarcinomas] and 36 NSCLCs with paired brain metastases. An independent set of 91 adenocarcinomas was also examined. EZH2 expression was statistically correlated with clinico-pathological information, and EGFR/KRAS mutation status. Results EZH2 expression was significantly (P<0.0001) higher in SCCs compared to adenocarcinomas and in brain metastasis relative to matched primary tumors (P=0.0013). EZH2 expression was significantly (P<0.0001) elevated in bronchial preneoplastic lesions with increasing severity. In adenocarcinomas, higher EZH2 expression significantly correlated with younger age, cigarette smoking and higher TNM stage (P=0.02 to P<0.0001). Higher EZH2 expression in adenocarcinoma was associated with worse recurrence-free survival (RFS; P=0.025; HR 1.54) and overall survival (OS; P=0.0002; HR 1.96). Furthermore, lung adenocarcinomas with low EZH2 levels and high expression of the lineage-specific transcription factor, TTF-1, exhibited significantly improved RFS (P=0.009; HR 0.51) and OS (P=0.0011; HR 0.45) which was confirmed in the independent set of 91 adenocarcinomas. Conclusion In lung, EZH2 expression is involved in early pathogenesis of SCC and correlates with a more aggressive tumor behavior of adenocarcinoma. When EZH2 and TTF-1 expressions are considered together, they serve as a prognostic marker in patients with surgically resected lung adenocarcinomas.

Purpose: Aberrant methylation of 5 gene promoter regions is an epigenetic phenomenon that is a major mechanism for silencing of tumor suppressor genes in many cancer types. There is limited information about the molecular changes involved in the pathogenesis of gallbladder carcinoma (GBC), including methylation status.Experimental Design: We investigated the aberrant promoter methylation profile of 24 known or suspected tumor suppressor genes in 50 GBCs and compared those results with the findings in 25 chronic cholecystitis (CC) specimens without cancer. The methylation-specific polymerase chain reaction and combined restriction analysis methods were used to detect methylation, and the results were confirmed by sequencing of cloned polymerase chain reaction products.Results: In GBC, gene methylation frequencies varied from 0% to 80%. Ten genes demonstrated relatively high frequencies of aberrant methylation: SHP1 (80%), 3-OST-2 (72%), CDH13 (44%), P15 INK4B (44%), CDH1 (38%), RUNX3 (32%), APC (30%), RIZ1 (26%), P16 INK4A (24%), and HPP1 (20%). Eight genes (P73, RAR␤2, SOCS-1, DAPK, DcR2, DcR1, HIN1, and CHFR) showed low frequencies (2-14%) of methylation, and no methylation of the remaining six genes (TIMP-3, P57, RASSF1A, CRBP1, SYK, and NORE1) was detected. In CC, methylation was detected for seven genes: SHP1 (88%), P15 INK4B (28%), 3-OST-2 (12%), CDH1 (12%), CDH13 (8%), DcR2 (4%), and P16 INK4A (4%). Significantly higher frequencies of methylation in GBC compared with CC were detected for eight genes (3-OST-2, CDH13, CDH1, RUNX3, APC, RIZ1, P16INK4A , and HPP1). Of those, four genes showed frequent methylation (>30%) in GBCs. The mean methylation index, an expression of the amount of methylated genes by case, was significantly higher in GBC (0.196 ؎ 0.013) compared with CC (0.065 ؎ 0.008; P < 0.001).Conclusions: Our study constitutes the most comprehensive methylation profile report available in GBC and demonstrates that this neoplasm has a distinct pattern of abnormal gene methylation. Whereas gallbladders from healthy individual were not available, our finding of methylation in CC cases without cancer suggests that this phenomenon represents an early event in the pathogenesis of GBC.