BAG1 and breast cancer: The overexpression of BAG-1 has been described in several breast cancer cell lines (Takayama et al, 1998; Brimmell et al, 1999), with the three isoforms demonstrating differing intracellular localisations: BAG-1L is predominantly nuclear, BAG-1S is predominantly cytoplasmic and BAG-1M is present in both the cellular compartments (Brimmell et al, 1999).