PIK3CA and breast cancer: Gene set enrichment analysis (GSEA) (based on a pre-ranked gene list using SAM's d-statistic) revealed that the expression of LINC00520 in basal-like breast cancer was significantly associated with upregulation of 26 of the Broad Institute's Molecular Signatures Database (mSigDB) Hallmark gene sets at a FDR < 5% (Supplementary Figure 3), including gene sets related to activation of the PI3K/AKT/mTOR pathway and epithelial-mesenchymal-transition (EMT) (Figure 3D).