Our previous studies revealed the propagation of cortical oscillatory waves in resting and stimulated rat basophilic leukemia (RBL-2H3) cells, as well as the recruitment of FMNL1, mDia3, and FHDC1 to the ventral actin waves that are Cdc42 dependent.31 These three actin nucleators belong to the family of 15 formins, a major class of actin-polymerizing proteins responsible for the elongation of the fast-growing, barbed ends of linear unbranched actin filaments. Here, FMNL1 is linked to acute basophilic leukemia.