SDC1 and breast cancer: 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.