PIK3R1 and breast carcinoma: Finally, among the genes up-regulated with FC≥2 (Table S2), we identified PIK3R1, the gene encoding the PI3K regulatory subunit, and two other genes of interest: HMGCS2, a nuclear gene encoding a mitochondrial matrix enzyme involved in ketogenesis and cholesterol synthesis, processes possibly implicated in the etiology or progression of breast cancer [18] and MAPT, a protein enhancing microtubule assembly and stability, that might be involved in taxane resistance [19].