PIK3CA and cancer: According to publicly available next-generation sequencing studies, i.e., the Cancer Cell Line Encyclopedia from the Broad Institute (https://portals.broadinstitute.org/ccle), and our own NGS data for HRAS and KRAS in MDA-MB-453 cells, the three TNBC cell lines used in the present study harbor different mutations in the components of the PI3K/Akt and MAPK/ERK pathways.