AKT1 and breast cancer: Thereafter, using direct knockdown of HER3 target by TRIM-ing method, without compensatory activation of other EGFR family members present in the cell, our results confirmed that G309A, S310Y, and P523S mutant bearing cells indeed drive cellular oncogenesis via AKT activation.37 Furthermore, BC cells expressing G309A, S310Y, and P523S mutants exhibited higher proliferation than H2-WT, S305C, and S310F expressing cells did, suggesting their potential aggressive phenotype.