Single cell RNA-sequencing of normal breast tissue samples before and after 12-week anti-progestin (ulipristal acetate) treatment

Vacuum-assisted biopsy (VAB) from normal breast tissue were obtained from women participating in the Breast Cancer - Anti-Progestin Prevention Study 1 (BC-APPS1). A baseline VAB was performed in the luteal phase of the menstrual cycle and a second VAB was performed after a 12-week anti-progestin (ulipristal acetate, daily 5mg oral tablet) treatment. Breast tissue minced into small fragments was digested overnight with collagenase/hyaluronidase. Following further digestion with trypsin and dispase, a dissociated breast single cell suspension was obtained and single-cell RNA-sequencing was performed. Standard workflow for the 10X Genomics Single Cell 3’ RNA Kit was used in two batches of 6 samples (3 participants per run with pre and post-ulipristal acetate treatment).