Gene expression signature of advanced pancreatic ductal adenocarcinoma using low density array on endoscopic ultrasound-guided fine needle aspiration samples.

AIMS: The purpose of this study was to investigate the clinical feasibility and utility of low-density array analysis on samples obtained from endoscopic ultrasound-guided fine needle aspiration biopsy in locally advanced and/or metastatic pancreatic ductal adenocarcinoma and chronic pancreatitis. PATIENTS AND METHODS: In this prospective multicenter study, we quantified candidate gene expression in biopsies sampled from 44 locally advanced and/or metastatic pancreatic carcinoma and from 17 pseudotumoural chronic pancreatitis using dedicated low-density array microfluidic plates. RESULTS: We first demonstrated that 18S gene expression is stable and comparable in normal pancreas and pancreatic cancer tissues. Next, we found that eight genes (S100P, PLAT, PLAU, MSLN, MMP-11, MMP-7, KRT7, KRT17) were significantly over expressed in pancreatic cancer samples when compared to pseudotumoural chronic pancreatitis (p value ranging from 0.0007 to 0.0215): Linear discriminative analysis identified S100P, PLAT, MSLN, MMP-7, KRT7 as highly explicative variables. The area under receiver operating curve establishes the clinical validity of the potential diagnostic markers identified in this study (values ranging from 0.69 to 0.76). In addition, combination of S100P and KRT7 gave better diagnosis performances (Area Under Receiver Operating Curve 0.81, sensitivity 81%, specificity 77%). CONCLUSION: We demonstrate that molecular studies on EUS-guided FNA material are feasible for the identification and quantification of markers in PDAC patients diagnosed with non-resectable tumours. Using low-density array, we isolated a molecular signature of advanced pancreatic carcinoma including mostly cancer invasion-related genes. This work stems for the use of novel biomarkers for the molecular diagnosis of patient with solid pancreatic masses.

DNA replication stress response involving PLK1, CDC6, POLQ, RAD51 and CLASPIN upregulation prognoses the outcome of early/mid-stage non-small cell lung cancer patients.

Lung cancer is the leading cause of cancer deaths worldwide. Clinical staging classification is generally insufficient to provide a reliable prognosis, particularly for early stages. In addition, prognostic factors are therefore needed to better forecast life expectancy and optimize adjuvant therapeutic strategy. Recent evidence indicates that alterations of the DNA replication program contribute to neoplasia from its early stages and that cancer cells are frequently exposed to endogenous replication stress. We therefore hypothesized that genes involved in the replication stress response may represent an under-explored source of biomarkers. Expressions of 77 DNA replication-associated genes implicated in different aspects of chromosomal DNA replication, including licensing, firing of origins, elongation, replication fork maintenance and recovery, lesion bypass and post-replicative repair were determined in primary tumors and adjacent normal tissues from 93 patients suffering from early- or mid-stage non-small cell lung cancer (NSCLC). We then investigated a statistically significant interaction between gene expressions and survival of early-stage NSCLC patients.The expression of five genes, that is, POLQ, PLK1, RAD51, CLASPIN and CDC6 was associated with overall, disease-free and relapse-free survival. The expression levels are independent of treatment and stage classification. Except RAD51, their prognostic role on survival persists after adjustment on age, sex, treatment, stage classification and conventional proliferation markers, with a hazard ratio of 36.3 for POLQ (95%CI 2.6-517.4, P=0.008), 23.5 for PLK1 (95%CI 1.9-288.4, P=0.01), 20.7 for CLASPIN (95%CI 1.5-275.9, P=0.02) and 18.5 for CDC6 (95%CI 1.3-267.4, P=0.03). We also show that a five-gene signature including POLQ, PLK1, RAD51, CLASPIN and CDC6 separates patients into low- and high-risk groups, with a hazard ratio of 14.3 (95% CI 5.1-40.3, P<0.001). This 'replication stress' metamarker may be a reliable predictor of survival for NSCLC, and may also help understand the molecular mechanisms underlying tumor progression.