The limited number of TNBC essential genes could be attributed to the large similarity between TNBC and HER2+ (i.e., only few genes were unique to TNBC), alternatively when comparing the enriched genes in TNBC vs HR+ BC only, we identified twenty TNBC essential genes (CDC123, CENPW, PWP2, ATP1A1, NOP2, YBX1, RPP4, PPP1CB, TSPYL5, HMGA1, SLC7A5, ATL2, CAD, CPAMD8, FA.BP5, SDC1, PPP1R1A, SLC2A1, MRPS17, and SOX9), Fig. S3. This evidence concerns the gene SOX9 and breast cancer.