While most selective BET inhibitors developed thus far target the BD2 domain, there is evidence to suggest that targeting the BD1 domain might be sufficient to elicit anti-proliferative effects,14 although this concept remains controversial given the potent tumour suppression seen using BD2-selective inhibitors.64 Interpretation of data gathered using BD-selective agents might be tempered based on a recent study that thoroughly tested a panel of 18 BETi for their selectivity against BD1 versus BD2 domains. Here, DEFB1 is linked to neoplasm.