BCAS2 (breast carcinoma amplified sequence 2), also designated DAM1 (DNA amplified in mammary carcinoma 1 protein) or spliceosome-associated SPF 27, is a ubiquitously expressed nuclear protein that was originally identified as being overexpressed in various breast cancer cell lines. BCAS2 is now known to be a component of the spliceosome, participating in the removal of introns from mRNA precursors. BCAS2 specifically interacts (in a ligandindependent manner) with TRbeta (thyroid hormone receptor beta), ERalpha (estrogen receptor alpha), ERbeta, PR (progesterone receptor), and PPARgamma (Peroxisome proliferator-activated receptor gamma ). BCAS2 functions as an ER coactivator and is capable of enhancing ER-mediated transcription. This suggests that BCAS2 is involved in the development of breast cancer.