PIK3R1 and breast carcinoma: The actin‐binding protein CapG interacts with p300/CBP and binds to the specific promoter of the regulatory subunit PIK3R1/P50 of PI3K, increasing PIK3R1/P50 transcription by acetylating lysine 27 of histone H3, thereby activating PI3K/Akt and conferring paclitaxel resistance in breast cancer patients37 (Figure 2).