PLAT and acute promyelocytic leukemia: APL cells express annexin A2[66] and S100A10[67] that form a heterotetrameric complex.54,55 This complex functions as a receptor for both tPA and plasminogen to effectively generate plasmin in a fibrin-free mechanism on the cell surface.[68] This may explain our results of significantly lower plasma levels of tPA in APL patients compared to healthy controls and the APL and non-APL AML groups.