RNA isolation and reverse transcriptase polymerase chain reaction
Total RNA was isolated from the breast cancer cell lines using the RNeasy mini kit (Qiagen, Valencia, CA, USA) following the manufacturer's instructions. The cDNA was generated using iScript cDNA synthesis (Bio-Rad). The cDNA was amplified using primers for Brk or β-actin as described by Kasprzycka and colleagues [25].