Basma et al. 2013 studied polymorphisms in genes encoding drug-metabolizing enzymes (DMEs) such as Cytochrome P450 2E1 (CYP2E1), NAD(P)H quinone oxidoreductase1 (NQO1), and N-Acetyltransferase1 (NAT1) and their influence on bladder cancer risk among Lebanese men. 54 unrelated men, below the age of 50 years with histologically confirmed bladder cancer, and 106 controls were included in the study. Significant clustering of CYP2E1 c1/c1 and NAT1*14A were seen in bladder cancer patients compared to controls. NAT1*14A allele, smoking, and occupational exposure to combustion fumes were observed to significantly contribute to the risk of developing bladder cancer. Although not statistically significant, CY2E1 c1/c1 genotype and prostate related symptoms were also found to be risk factors for bladder cancer. This study is a follow up to Yassine et al. 2012 which studied NAT1 genotypes in the same population, subject group ID: 109800.G.1. 

Bu et al. (2004) studied the frequencies of alleles and genotypes for CYP1A1, NAT2, GSTs, MTHFR, MTR (MS), and NQO*1 genes among Arabs.  Of the studied group, 95% were from Saudi Arabia, and 5% were from Jordan, Syria, Lebanon, and Yemen.  The mean age was 37 years, and male to female ratio was (25:1).  Allele frequency for the NQO*1 C609T variant was 24% in the studied Arab group.

Ouerhani et al. (2013) conducted a case-control study to assess the impact of CYP1A1*2A (CYP1A1 T6235C); NQO1*2 (NQO1 C609T); TPMT*2 (TPMT G238C) and TPMT A719G polymorphisms on the risk of developing ALL.  The frequencies of TPMT*2, TPMT A719G, NQO1*2, and CYP1A1*2 variants were examined in 100 patients with ALL and 106 healthy controls.  The NQO1 609CT genotype was overrepresented in patients and was associated with an aggravating effect compared to the reference group with the NQO1 609CC genotype (p = 0.028, OR = 1.41; CI 95%: 1.04-1.93).  The TPMT*2, TPMT 719*G, and CYP1A1*2 variants did not appear to influence ALL susceptibility (p > 0.05).