HNF4A and breast cancer: We performed immunoblot analysis to probe for HSL, phospho-HSL (S563), and HNF4α in tumor and NAT, as well as corresponding control mammary tissues, from three well-characterized breast cancer patient-derived xenograft (PDX) models (HCI002, HCI009, HCI010) and a transgenic model of MYC-driven TNBC (MTB-TOM)26,27.