MAPK3 and breast carcinoma: ER-α36 may therefore be associated with MAPK/ERK and PI3K/Akt pathways, and ER-α36 knockdown directly inhibits ERK1/2 and Akt activation, which is consistent with previous studies which report that both MAPK/ERK and PI3K/Akt signaling activation are regulated by ER-α36 in breast cancer [19], [23], [25], [29], [39], [40].