ESR1 and lung cancer: The five non‐TNBC cell lines included two estrogen receptor‐positive (ER+) breast cancer cell lines, MCF7‐C3 and T47D‐clover, one human epidermal growth factor receptor 2 positive (HER2+) breast cancer cell line, BT474‐clover, one lung cancer cell line, A549‐C3, and one cervical cancer cell line, HeLa‐C3.