ESR1 and breast cancer: When CAMA-1 along with aromatase-transfected MCF-7(MCF7/Aro) and ZR75-1(ZR75-1/Aro/CL.10) cells were cultured in suspension in ultra-low adhesion culture plates to mimic the circulating tumor cells (CTCs), interestingly, all of these three ERα+ breast cancer cell lines expressed more aromatase in suspension culture when compared to the adhesion culture.