title: Interaction of drug metabolizing cytochrome P450 2D6 poor metabolizers with cytochrome P450 2C9 and 2C19 genotypes modify the susceptibility to head and neck cancer and treatment response.
abstract: The present case-control study attempted to investigate the association of poor metabolizer (PM) genotypes of cytochrome P450 2D6 (CYP2D6*4 and CYP2D6*10) with squamous cell carcinoma of head and neck (HNSCC) and treatment response in patients receiving chemotherapy or combination of chemo- and radiotherapy. Cases with the PM genotypes of CYP2D6 displayed a significantly increased risk for HNSCC as compared to wild type genotypes. The risk was found to further increase in cases (up to 4.8) carrying combination of PM genotypes of CYP2D6, CYP2C9 (CYP2C9*2) or CYP2C19 (CYP2C19*2), suggesting that synergism amongst the PM genotypes of drug metabolizing CYPs leads to impairment in the detoxification of the tobacco carcinogens. A small increase in the risk in tobacco (chewers or smokers) or alcohol users in cases with CYP2D6*4 allele while no change or even a small decrease in risk in cases with CYP2D6*10 allele when compared to non-tobacco or alcohol users have suggested that CYP2D6 genotypes alone do not appear to interact significantly with environmental risk factors in modifying the susceptibility to HNSCC. Furthermore, most of the cases carrying PM genotypes of CYP2D6 did not respond to the treatment. Moreover, higher prevalence of non-responders among cases carrying combination of CYP2D6*4 or CYP2D6*4, CYP2C9*2 and CYP2C19*2 have demonstrated that interaction of PM genotypes may not only significantly modify the susceptibility to HNSCC but also the treatment response.
authors: Developmental Toxicology Division, Indian Institute of Toxicology Research (Formerly: Industrial Toxicology Research Centre), Council CSIR, P.O. Box 80, Mahatma Gandhi Marg, Lucknow 226 001, India.
authors: Sunishtha S
authors: SS
authors: Yadav
authors: Munindra
authors: M
authors: Ruwali
authors: Mohan C
authors: MC
authors: Pant
authors: Pragya
authors: P
authors: Shukla
authors: Ram L
authors: RL
authors: Singh
authors: Devendra
authors: D
authors: Parmar
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000628:therapy; D016022:Case-Control Studies; D065731:Cytochrome P-450 CYP2C19; D065729:Cytochrome P-450 CYP2C9; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D019389:Cytochrome P-450 CYP2D6