We identified DRAK2 as showing consistent changes in expression. This predominantly nuclear serine -threonine kinase has similarity to the DAP kinases and is involved (at least in certain cell types) in initiation of apoptosis (Sanjo et al, 1998) . Unsupervised hierarchical clustering of our expression data (Supplementary Figure S2 ) selected a cluster of genes showing a similar pattern of upregulation with COX-2 inhibition. This cluster of genes have either known nuclear localisation within the cell or have a bipartite nuclear localisation signal, which suggests their ability to traffic to the nucleus. Many of these are known to be involved in transcriptional regulation or in the induction or potentiation of apoptosis. Prior expression analyses have previously identified nuclear proteins as significantly over-represented in genes induced by aspirin treatment in colon cancer cells (Hardwick et al, 2004 ) and a mechanism regulating the nuclear trafficking of DRAK2 has recently been suggested (Kuwahara et al, 2008) .