AKT activation in PIK3CA mutation model and AKT inhibition desensitizes model EC039 to Trastuzumab therapy. A. Western blot analyses of EC039 and EC044 PDECX models. Three xenograft tumors in both PIK3CA mutation EC039 and wild type EC044 model were harvested, and total proteins were extracted and analyzed with the indicated antibodies. Blots were quantified by density scanning and the graphed data (Mean + SD) represents the quantification of the ratio of protein expression to GAPDH. Significant changes (p < 0.0004) between the two models are labeled as *. B. Combination with Trastuzumab and AKT selective inhibitor AZD5363 in PIK3CA mutation model EC039.