ABSTRACT: BACKGROUND:Ataxia telangiectasia mutated (ATM) gene plays a key role in response to DNA lesions and is related to the invasion and metastasis of malignancy. Epidemiological studies have indicated associations between ATM rs1801516 polymorphism and different types of cancer, but their results are inconsistent. To further evaluate the effect of ATM rs1801516 polymorphism on cancer risk, we conducted this meta-analysis. METHODS:Studies were identified according to specific inclusion criteria by searching PubMed, Web of Science, and Embase databases. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) under recessive, dominant, codominant, and overdominant models of inheritance were calculated to estimate the association between rs1801516 polymorphism and cancer risk. RESULTS:A total of 37 studies with 12,879 cases and 18,054 controls were included in our study. No significant association was found between rs1801516 polymorphism and cancer risk in overall comparisons (AA vs GG?+?GA: OR?=?0.91, 95% CI, 0.78-1.07; AA+GA vs GG: OR?=?1.00, 95% CI, 0.90-1.11; AA vs GG: OR?=?0.89, 95% CI, 0.75-1.06; GA vs GG: OR?=?1.01, 95% CI, 0.91-1.13; GG?+?AA vs GA: OR?=?1.00, 95% CI, 0.88-1.10). However, after subgroup analyses by region-specified population, significant associations were found in European (AA vs GG?+?GA: OR?=?0.79, 95% CI, 0.65-0.96, P?=?0.017; AA vs GG: OR?=?0.79, 95% CI, 0.65-0.96, P?=?0.017), South American (AA+GA vs GG: OR?=?2.15, 95% CI, 1.37-3.38, P?=?0.001; GA vs GG: OR?=?2.19, 95% CI, 1.38-3.47, P?=?0.001; GG?+?AA vs GA: OR?=?0.46, 95% CI, 0.29-0.72, P?=?0.001), and Asian (AA vs GG?+?GA: OR?=?7.45, 95% CI, 1.31-42.46, P?=?0.024; AA vs GG: OR?=?7.40, 95% CI, 1.30-42.19, P?=?0.024). Subgroup analyses also revealed that compared with subjects carrying a GG genotype, those carrying a homozygote AA had a decreased risk for breast cancer (AA vs GG: OR?=?0.76, 95% CI, 0.59-0.98, P?=?0.035), and the homozygote AA was associated with decreased cancer risk in subjects with family history (AA vs GG: OR?=?0.68, 95% CI, 0.47-0.98, P?=?0.039). CONCLUSIONS:ATM rs1801516 polymorphism is not associated with overall cancer risk in total population. However, for subgroup analyses, this polymorphism is especially associated with breast cancer risk; in addition, it is associated with overall cancer risk in Europeans, South Americans, Asians, and those with family history.