The above results on the regulation of FA turnover by ErbB2 signalling were also confirmed using time-lapse video microscopy on BT20 breast cancer cells (these cells express high level of endogenous ErbB2 and are responsive to Herceptin, Yakes et al, 2002; Nagata et al, 2004) transfected with EYFP-paxillin. Here, PXN is linked to breast cancer.