ESR1 and breast cancer: To identify endogenous targets of E2-regulated alternative splicing and the influence of AKT on this process, we performed ExonHit Apoptosis Splice Array analysis of ERα-positive/E2-dependent MCF-7 breast cancer cells (MCF-7p) and the same cell line overexpressing constitutively active AKT (MCF-7AKT) with or without E2 treatment.