S100A8 and S100A9 are mainly found as cytosolic protein in neutrophils and monocytes (Ahmad et al. 2003) but they have also been detected in other cell types and tissues such as leukocytes, fibroblasts, tumour cell lines and bone marrow (Dale et al. 1985, Rahimi et al. 2005) including both squamous epithelia and non-squamous cell types (Matsumoto et al. 1997).