Since several known human NGTxCs target estrogen receptor signaling, fluorescent BAC reporters for ERα-induced proliferation and cell cycle progression in human ERα-positive MCF7 breast cancer cells will be included (Duijndam et al., 2021; Duijndam et al., 2022), as well as a panel of CRISPR-based endogenously tagged fluorescent human induced pluripotent stem cell reporter lines that can be differentiated to relevant lineages including progenitor cells of mammary epithelial cells and hepatocytes. Here, ESR1 is linked to breast carcinoma.