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

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

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

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