PPP1CA and breast carcinoma: Importantly, given that PML is frequently lost in human cancer47, our study suggests that aberrant cytoplasmic retention of PP1α caused by PML loss or the amplification of PPP1CA might represent a common mechanism underlying MAPK activation in cancers that lack activating mutations or gene rearrangements among MAPK signaling components, such as breast cancer and CaP13–17,48,49.