WT1 and breast cancer: In the subgroup analyses, after PS adjustment, WT1 methylation was associated with breast cancer risk in both the younger (< 60-years-old) and older (≥60-years-old) groups, with ORs of 2.64 (95% CI: 1.31–5.32, P = 0.01) and 4.72 (95% CI: 1.31–16.97, P = 0.01), respectively.