SERPINE1 and breast carcinoma: uPA and PAI-1 do not only have proteolytic characteristics, but also have impact on the fundamental cellular processes, such as chemotaxis, migration, invasion, adhesion, proliferation and angiogenesis.2–6 uPA and PAI-1, as part of the fibrinolytic system, are the first factors with a confirmed clinical role in breast cancer (level of evidence I).7,8 According to the conclusions of the meta-analysis by Look et al. 7, uPA and PAI-1 are in addition to axillary lymph node involvement the most important independent prognostic factors.