CDKN2A and breast cancer: To examine the role of Dab2 as a tumour suppressor in breast cancer, we chose to stably downregulate Dab2 expression utilising shRNA-mediated technology in the normal human mammary epithelial cell line MCF10A1, which harbours a defective p16/INK4a locus (Tang et al, 2003, 2007) allowing for continued cell growth.