In a series of breast cancer patients with BMs, 22 out of 27 of primary tumours (81%) were S100A4 positive compared with 18 out of 117 (15%) in a group with known non-metastatic breast cancer (Rudland et al, 2000) as shown in Figure 5 (Fisher's exact test, P<0.0001). Here, S100A4 is linked to breast cancer.