ESR1 and breast cancer: Then, we increased the expression of TMEM97 in the MCF7 and T47D cells as they are human breast cancer cell lines with estrogen and progesterone receptors (ER-positive breast cancer cells) by lentivirus infection, with GFP as an indication of successful transductions and predominant localization of TMEM97 in the cytoplasm (Supplemental Figure S1B).