PIK3CA and breast neoplasm: However, there was no significant difference in the GI50s of Pten WT and Pten−/− MEFs, MycOE Pik3ca Mut and MycOE Pten Null mouse breast tumor cell lines or PTEN WT and PTEN−/− HCT116 cells after treatment with the cell cycle inhibitor Palbociclib (Supplementary Figure S10) (57), suggesting that loss of PTEN does not result in an increased sensitivity to cell cycle inhibition in the cell lines tested.