Flatmark et al (2003) has demonstrated that S100A4 nuclear localisation correlated with tumour stage and aggressiveness of colorectal carcinoma. A recent study has shown that A100A1, another member of the S100 family of proteins, can interact with S100A4 to modulate the effect of S100A4 on their metastatic abilities (Wang et al, 2005). This evidence concerns the gene S100B and colorectal carcinoma.