S100A4 and breast cancer: This was followed by reports that transfection of either human or rat S100A4 DNA can induce a metastatic phenotype upon nonmetastatic rat mammary tumour cells (Davies et al, 1993; Grigorian et al, 1993), whereas inhibition of S100A4 expression in metastatic cells can revert cells to a less metastatic phenotype (Maelandsmo et al, 1996).