PIK3CA mutation associates with superior disease-free survival. (a) Kaplan-Meier curves for disease-free survival (DFS) based on PIK3CA mutation status in all patients. (b) Kaplan-Meier curves comparing overall survival (OS) in all patients with PIK3CA wild-type and mutant tumors. (c) Kaplan-Meier curves for DFS based on PIK3CA mutation status in patients with estrogen receptor (ER)-positive breast cancer. (d) Kaplan-Meier curves comparing OS in ER-positive breast cancer patients (ER status at time of recurrence) with PIK3CA wild-type and mutant tumors, from the time of relapse.