A marginal significant association between the CTLA-4 -1661A/G polymorphism and increased cancer risk was detected in population based group under heterozygote model, dominant model and allele model (GA vs. AA: OR = 1.74, 95%CI = 1.49–2.04; GA+GG vs. AA: OR = 1.60, 95%CI = 1.38–1.86; G vs. A: OR = 1.37, 95%CI = 1.20–1.56).The remaining pooled ORs from this meta-analysis were not significant (P>0.05) (Table 3). Here, CTLA4 is linked to cancer.