PIK3CA and breast cancer: In line with this, PI3K pathway activity was found to be associated with higher grade and worse prognosis in breast cancer, high grade serous ovarian cancer, prostate cancer, and esophageal cancer (Verhaegh et al., 2014; Creemers et al., 2018; van de Stolpe et al., 2019a; Sieuwerts et al., 2020; van Lieshout et al., 2020).