Early indications of a role for BCL3 in genome integrity were posited when BCL3 was shown to suppress p53 via upregulation of Hdm2 in response to UVB induced DNA damage of breast cancer cells [105] and when shRNA suppression of BCL3 was shown to induce aneuploidy in HeLa cells with accompanying increases in phospho-ATM, gamma-H2Ax and a concomitant decrease in phospho-CHK1 [114]. Here, BCL3 is linked to breast cancer.