BRCA1 dysfunction in sporadic basal-like breast cancer

Breakthrough scientists have identified a high prevalence of BRCA1 dysfunction in basal-like breast cancers. This finding could be exploited to develop novel targeted therapies for this particular type of breast cancer.

The scientists analysed sporadic breast cancers expressing the basal marker cytokeratin 5/6, and age- and grade-matched controls, for down-regulation of BRCA1. Although BRCA1 promoter methylation was no more common in basal-like cancers, BRCA1 messenger RNA expression was twofold lower in basal-like breast cancers compared to matched controls. ID4, a negative regulator of BRCA1, was expressed at 9.1-fold higher levels in basal-like breast cancer, suggesting a potential mechanism of BRCA1 down-regulation. In addition, they found that 63% of metaplastic breast cancers, a rare type of basal-like cancers, had significantly higher levels of BRCA1 gene promoter methylation than controls (12%).

The high prevalence of BRCA1 pathway dysfunction identified in this study could be exploited in the development of novel approaches to targeted treatment of basal-like breast cancer.

BRCA1 dysfunction in sporadic basal-like breast cancer. Turner et al. Oncogene. 2007 26(14): 2126-2132.