Tumor metastasis plays a key role in assessing treatmentstrategies and an important factor in determining patient prognosis.  Not surprisingly, significant effort has beenfocused on elucidating the molecular basis behind tumor metastasis.  This understanding may allow development ofdiagnostic and prognostic tools and likely provide  novel therapeutic targets.   

In a recent study by Crawford et al. published in PNAS, itwas shown that Brd4, a ubiquitously expressed 200-kDa nuclear protein broadlyexpressed in many tissues, significantly reduced tumor growth and metastasiswhen implanted into mice.  Further,Microarray analysis performed by the same group identified a correlationbetween Brd4 activation and disease progression/patient survival.

Together, this evidence strongly suggests that Brd4 plays akey role in breast cancer progression and an underlying mechanism of manymetastasis-predictive gene signatures.

Although it remains to be determined if Brd4's role is thatof a proximal factor or an intermediary molecule of some other inherited factorthat drives the progression of breast cancer, its functional importance isemerging as both a diagnostic and prognostic tool with therapeuticsignificance.