LIG4 and cancer: Heterogeneities were observed among several studies for LIG4 D501D polymorphism and overall cancer susceptibility (homozygous: P = 0.044; dominant: P = 0.048;) and T9I (homozygous: P < 0.001; recessive: P < 0.001; dominant: P < 0.001; allele: P < 0.001).