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).  Three polymorphisms in the CYP1A1 gene were analyzed: T3801C, A2455G, and C2453A.  Allelic frequencies among the studied group were 20% for 3801C, 7% for 2455G, and 19% for 2453A.

Al-Achkar et al. (2014) we investigated the associations of polymorphisms in the cytochrome P450 gene (CYP1A1) and the glutathione S-transferase genes (GSTM1 and GSTT1) with chronic myelogenous leukemia (CML).  A total of 126 patients with CML and 172 healthy volunteers were genotyped.  Logistic regression analyses showed significant risk of CML associated with CYP1A1 Val allele [odds ratio (OR) 3.3, 95% confidence intervals (CI) 1.96-5.53], (p < 0.0001) while CYP1A1 Val/Val homozygotes were observed only in the CML patients.  There was statistically significant difference in the frequency of GSTM1 and GSTT1 null genotypes.  The GSTT1-null genotype was slightly higher in 27% of CML cases and 17% of controls (OR 1.98, 95% CI 1.12-3.5) (p < 0.020).  The GSTM1 null was higher in 43% of CML cases and 23% of controls (OR 2.55, 95% CI 1.54-4.22) (p < 0.00024).  Individuals carrying the CYP1A1 Ile/Val (AG) and GSTM1 null genotype have 9.9 times higher risk to be CML than those carrying CYP1A1 Ile/Ile (AA) and GSTM1 present genotype (OR 9.9, 95% CI 2.7-36.3) (p < 0.0001).  Al-Achkar et al. (2014) concluded that the association of the GSTM1 null genotype, either alone or in combination with GSTT1 null, with CYP1AI heterozygous leads to the CML risk.