PLD1 and breast cancer: We decided to focus on phospholipases D (PLDs), which catalyzes the hydrolysis of phosphatidylcholine (PC) into phosphatidic acid (PA), for three reasons: (1) PLD1 and PLD2 are two well-known targets of RalA and RalB (Jiang et al., 1995; Luo et al., 1998; Vitale et al., 2005), (2) PLD2 controls exosome secretion in breast cancer cells (Ghossoub et al., 2014), and (3) PLDs impact cancer progression (Bruntz et al., 2014).