PIK3CA and ductal breast carcinoma in situ: For the PI3K inhibitor LY294002, The IC50 was found to be the lowest in the MCF10.Neo T cells (8.90 μM), followed by the MCF10.AT1 cells (17.60 μM), with the highest IC50 value (21.88 μM) in the MCF10.DCIS cells (Fig. 2A,B).