ESR1 and neoplasm: Interestingly, triple‐negative breast cancer (TNBC) cells were shown to secrete higher levels of IL‐4 in the tumor milieu, compared with estrogen receptor (ER)‐positive breast cancer cells, contributing to their proliferation and metastatic potential [4], and recently, an IL‐4 mediated boost in glucose and glutamine metabolism was identified as a driver of TNBC cell growth [7].