Cytochrome P450 (P450) enzymes are mixed-function oxidases that catalyze the metabolism of xenobiotics and endogenous biochemicals. Selective inhibitors are needed to accurately distinguish the contributions of individual P450 enzymes in the metabolism of drugs and the activation of procarcinogens in human tissues, but very frequently these enzymes have substantial overlapping selectivity. We e...

Gastric carcinoma is a heterogeneous malignant disease involving genetic factors. To identify predictive markers for gastric cancer treatment in Chinese patients, we evaluated the association between polymorphisms of the gene encoding cytochrome P450 2A6 (CYP2A6) and outcomes of S-1 plus oxaliplatin (SOX) chemotherapy treatment. Clinical data on 60 consecutive gastric cancer patients receiving ...

Urinary cotinine, one of the main metabolites of nicotine, has been widely used as a biomarker for assessment of direct or passive exposure to cigarette smoke. However, there is wide variation of the cotinine level among smokers who smoke the same number of cigarettes. To use urinary cotinine as a proper exposure-biomarker for cigarette smoke, interindividual variations of cotinine formation mu...

OBJECTIVES To assess the association between the variant of Cytochrome P450 2A6 whole gene deletion (CYP2A6*4) polymorphism and risk of lung cancer. METHODS Two investigators independently searched the PubMed, Elsevier, EMBASE, Web of Science, Wiley Online Library and Chinese National Knowledge Infrastructure (CNKI). Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for CYP2A6*4...

BACKGROUND Genetic and metabolic factors associated with nicotine metabolism may be related to smoking behavior. AIM To assess the prevalence of allelic and genotype variants of CYP2A6 in a sample of Chilean subjects and to evaluate their relationship with smoking and tobacco dependence. MATERIAL AND METHODS The genotype frequencies for *2, *3 and *4 of CYP2A6*1 (wild type) gene were determ...

By using the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP), a novel polymorphism of CYP2A6, CYP2A6*6, was detected in 0.4% of the Japanese population. To study the enzymatic properties of the CYP2A6.6 protein with a single amino acid substitution of arginine 128 to glutamine, both this isozyme and the CYP2A6.1 protein (wild-type) we...

OBJECTIVE Case control studies in adults suggest that defective alleles in the gene that codes for the hepatic cytochrome P450 2A6 (CYP2A6) protect against nicotine dependence (ND) and higher levels of cigarette consumption. These two hypotheses were tested in young adolescents. DESIGN Self reports of tobacco use and ND symptoms were collected every 3-4 months in a prospective study of 1293 g...

Tegafur is a prodrug of 5-fluorouracil (5-FU) consisting of a new class of oral chemotherapeutic agents, tegafur/uracil and S-1, which are classified as dihydropyrimidine dehydrogenase inhibitory fluoropyrimidines. It is bioactivated to 5-FU via 5'-hydroxylation mediated by cytochrome P-450 (CYP). However, which isoform(s) of CYP is responsible for the bioactivation process of tegafur remains u...

We developed a population pharmacokinetic (PPK) model of S-1 including the cytochrome P450 (CYP) 2A6 genotype and then used this PPK model to assess the influence of the CYP2A6 genotype on PK parameters of S-1 and the relationship between toxicity and the individual maximum concentrations (Cmax) or the area under the concentration-time curve (AUC) of 5-fluorouracil (5-FU) in Japanese patients w...

Human exposure to trans-cinnamic aldehyde [t-CA; cinnamaldehyde; cinnamal; (E)-3-phenylprop-2-enal] is common through diet and through the use of cinnamon powder for diabetes and to provide flavor and scent in commercial products. We evaluated the likelihood of t-CA to influence metabolism by inhibition of P450 enzymes. IC50 values from recombinant enzymes indicated that an interaction is most ...