SPRY4 and breast cancer: We first performed a meta-analysis of six published breast cancer gene expression profiles representing a total of 1107 tumours to assess the gene expression of Spry1, Spry2 and Spry4. Spry3 was omitted from the analysis since this is considered a minor orthologue, transcript levels are low across published datasets, and it is not represented on the Affymetrix U133A GeneChip.