Hans Clevers, et al. highlighted that (1) neuregulin 1 was an essential element for efficient generation and long-term expansion for breast cancer organoids; (2) Wnt3A was not essential for culture conditions; (3) EGF was a double-edged sword for low concentration impeding proliferation and high concentration leading to organoid sinking and gradual loss of 3D organization; (4) SB202190 at high concentration was detrimental to effective establishment of breast cancer organoids [38]. This evidence concerns the gene NRG1 and breast cancer.