MAD2L1 and breast cancer: A2 targets MAD2L1, leading to SAC dysfunction, which causes chromosomal missegregation, aneuploidy, and subsequent micronuclei formation.[15, 16] To elucidate the molecular mechanism by which A2 induces BC cell apoptosis through targeting MAD2L1, we profiled the chromosome content in T24 and UMUC‐3 cells treated with A2.