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Objectives: The aim of this study was to evaluate transcript levels of all 49 human ATP-binding cassette transporters (ABCs) in one of the most drug-resistant cancers, namely, the pancreatic ductal adenocarcinoma (PDAC). Association of ABCs levels with clinical-pathologic characteristics and KRAS mutation status was followed as well., Methods: Tumors and adjacent nonneoplastic tissues were obtained from 32 histologically verified PDAC patients. The transcript profile of ABCs was assessed using quantitative real-time polymerase chain reaction with a relative standard curve. KRAS mutations in exon 2 were assessed by high-resolution melting analysis and sequencing., Results: Most ABCs were deregulated in PDAC and 10 ABCs were associated with clinical-pathologic characteristics. KRAS mutations did not change the global expression profile of ABCs., Conclusions: The expression of ABC transporters was significantly deregulated in PDAC tumors when compared to nonmalignant tissues. The observed up-regulation of ABCB4, ABCB11, ABCC1, ABCC3, ABCC5, ABCC10, and ABCG2 in tumors may contribute to the generally poor treatment response of PDAC. The up-regulation of ABCA1, ABCA7, and ABCG1 implicates a serious impairment of cellular cholesterol homeostasis in PDAC. On the other hand, the observed down-regulation of ABCA3, ABCC6, ABCC7, and ABCC8 suggests a possible role of stem cells in the development and progression of PDAC.

Objectives: Pancreatic carcinoma etiology and molecular pathogenesis is weakly understood. According to the assumption that genetic variation in carcinogen metabolism further modifies the risk of exposure-related cancers, an association of functional polymorphisms in oxidative stress-modifying genes superoxide dismutase 2 (SOD2 [Ala16Val, rs4880]), SOD3 (Arg231Gly, rs1799895), nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase (NQO1 [Pro187Ser, rs1800566], and NQO2 (Phe47Leu, rs1143684) with pancreatic cancer risk was studied., Methods: Polymorphisms were studied by allelic discrimination., Results: In a hospital-based case-control study on 500 individuals (235 cases and 265 controls) of Czech white origin, SOD2, SOD3, NQO1, and NQO2 polymorphisms showed no significant association with pancreatic cancer risk. Major lifestyle factors such as smoking and alcohol, coffee, or tea consumption did not modify the effect of the studied polymorphisms., Conclusions: The first European study of the SOD2, SOD3, NQO1, and NQO2 roles in pancreatic cancer etiology did not find significant associations. Despite this observation, other populations with different lifestyle(s) may be at risk and should be further studied.

Objectives: Pancreatic carcinoma etiology and molecular pathogenesis are weakly understood. Based on the assumption that genetic variation in carcinogen metabolism further modifies the risk of exposure-related cancers, we studied the association of polymorphisms in the tobacco carcinogen-metabolizing gene CYP2A13 (Arg101Stop) and the alcohol-metabolizing genes ADH1B (Arg48His) and ADH1C (Ile350Val) with pancreatic cancer risk., Methods: Polymorphisms were studied by allelic discrimination., Results: In a hospital-based case-control study, CYP2A13 variant alleles coding an inactive enzyme were found in 7 of 265 cancer-free controls and in none of 235 pancreatic carcinoma patients. Neither ADH1B or ADH1C polymorphisms alone nor their combinations showed a significant effect on pancreatic cancer risk., Conclusions: The first study of the roles of CYP2A13, ADH1B, and ADH1C in pancreatic cancer etiology suggested that the controls may have a lower ability to bioactivate tobacco-derived procarcinogens than the cases.