Figure 4.

Phenylbutyrate down-regulates BRCA1 expression in head and neck cancer cell lines. Cells were treated with 2 mM phenylbutyrate (PB) for 3 days before the cells were harvested and the levels of BRCA1 protein analyzed with Western blot. The relative amount of BRC1 protein in the phenylbutyrate-treated samples is expressed as a fraction of the BRCA1 protein level in untreated controls.