BCAS1 was identified through positional cloning and was found to be overexpressed in most but not all breast cancer cells lines. Little is known about this protein; BCAS1 is cytoplasmically localized and is thought to form homodimers through coiled-coil structures. High levels of BCAS1 mRNA are seen in brain and prostate tissues, with lower amounts observed in colon, intestine and testis. Cells engineered to overexpress BCAS1 did not lose anchorage-dependent growth or increase their rate of growth, suggesting that BCAS1 is not a prototypical oncogene. The BCAS1 gene was also found to be amplified in other carcinomas such as pancreatic carcinoma, suggesting that BCAS1 may play in important role in the control of cell proliferation.