SUM44 is a model cell line for ERα positive breast cancer with the 8p11 amplicon.
WHSC1L1 is a driving oncogene from the 8p11 amplicon in SUM44 cells.
SUM44 breast cancer cells have high ERα expression, regulated by WHSC1L1 knockdown.
ERα is required for growth and survival of SUM44 cells but is estrogen-independent.
WHSC1L1 knock-down re-sensitizes ERα to estradiol for binding to essential genes.