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 ligand-independent manner) with TR∫ (thyroid hormone receptor beta), ERå (estrogen receptor alpha), ER∫, PR (progesterone receptor), and PPAR© (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.