There were four groups of Caucasians [19, 21, 25, 26], three of Asians [20, 23, 24] and three of mixed races [22, 27, 28] in this meta-analysis. As for age groups, there were seven groups of adult AML [19, 20, 22–26] and four groups of childhood AML [21, 25, 27, 28] in this study. Noticeably, the study conducted by Aydin-Sayitoglu et al… [25] involved two subgroups regarding adult AML and childhood AML, respectively. The distributions of CYP1A1 MspI genotype as well as the genotyping methods of the included studies are presented in Table2. The genetic distributions of the control groups in all included
studies were consistent with HWE. Table 2 Distribution of CYP1A1 MspI genotypes among acute myeloid leukemia GSK3235025 cell line cases and controls included in the meta-analysis First Author Year Genotyping method Cases Controls HWE (control) CC TC TT CC TC TT Chi-squre P Balta 2003 PCR-RFLP 0 6 20 7 35 103 2.862 > 0.05 D’Alo 2004 PCR-RFLP 0 17 161 0 42 226 1.937 > 0.05 Clavel 2005 PCR-RFLP 0 5 22 0 24 81 1.748 > 0.05 Aydin-Sayitoglu 2006 PCR-RFLP 5 24 65 4 30 106 1.049 > 0.05 Bolufer 2007 Real-time PCR 0 31 168 2 84 317 2.062 > 0.05 Jiang 2008 PCR-RFLP 19 50 29 26 50 44 2.610 > 0.05 Majumdar 2008 PCR-RFLP 30 39 41 9 51 66 0.040 > 0.05 Yamaguti 2009 learn more PCR-RFLP 9 59 65 6 32 95 2.199 > 0.05 Bonaventure 2012 Infinium platform 2 7 41 7 87 454 1.435 > 0.05 Kim 2012 PCR-RFLP 61 219 135 263 801 636 0.170 > 0.05 Test of heterogeneity As shown in Table3, we analyzed the heterogeneity for the
allelic contrast (C allele versus T allele), homozygote comparison (CC versus TT) and dominant model (CC + TC versus TT), respectively. Evident heterogeneities were observed for the overall data in the three genetic comparisons (C allele versus T allele: P = 0.000 for Q-test; CC versus TT: P = 0.026 for Q-test; CC + TC versus TT: P = 0.002 for Q-test). Additionally, I-square value is another index for the heterogeneity test [29], with value less than 25% indicating low, 25% to 50% indicating moderate, and greater than 50% indicating high heterogeneity. The I-square values were 71.7%, 55.9% and 65.5 for the overall data of the allelic contrast, homozygote comparison and dominant model, respectively, indicating marked heterogeneities between the studies. Hence, oxyclozanide the random-effect models were utilized. However, when subgroup analyses regarding ethnicity and age groups were further conducted, we found loss of heterogeneities in the subgroups regarding Caucasians and childhood AML, respectively. Table 3 Main results of the pooled data in the meta-analysis No. (cases/controls) C allele vs T allele CC vs TT (CC + TC) vs TT OR (95%CI) P (OR) P (Q-test) OR (95%CI) P (OR) P (Q-test) OR (95%CI) P (OR) P (Q-test) Total 1330/3688 1.13 (0.87-.1.48) 0.349 0.000 1.72 (0.99-3.01) 0.055 0.026 1.16 (0.86-1.55) 0.326 0.