The estimated lifetime risk of developing breast cancer from altered expression of a single gene such as, COL4A1, CD99, ANXA2, MPP2, EGFR, CDK4, BTF3, RAB31, TOP2A or SERBP1 was 0.76, 1.18, 1.57, 1.62, 1.62, 1.85, 1.91, 0.73, 1.96 or 0.63%, respectively compared to 0.61% risk of developing glioblastoma in normal population. This evidence concerns the gene CD99 and breast cancer.