Although PAI-1, a potent inhibitor of uPA, would be expected to show anti-tumour effects, multiple studies report a paradox in its function where its expression positively correlates to pro-tumorigenic effects, including resisting apoptosis, increased cell migration and angiogenesis as well as worsened clinical outcome (reviewed in detail by Kubala and Declerck 2019) [104]. The gene discussed is PLAU; the disease is neoplasm.