By producing PI(3)P and PI(3,4)P2, PI3KC2α plays an essential role during development and its loss or inactivation leads to multiple pathological processes.[34] Besides its enzymatic activity, we recently described a scaffold function of PI3KC2α that is necessary for keeping genome integrity by preventing mitotic defects in breast cancer cells.[12] Accordingly, loss of PI3KC2α in breast cancer initially delays tumor growth but finally leads to the selection of more aggressive clones. Here, PIK3C2A is linked to breast cancer.