Differential expression of anti-silencing function 1B histone chaperone in triple negative breast cancer.
Women diagnosed with triple negative breast cancer can benefit neither from endocrine therapy nor from HER2-targeted therapies (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding anti-silencing function 1B histone chaperone, ASF1B, when comparing the tumor cells of patients with triple negative breast cancer to normal mammary ductal cells (2). ASF1B was also differentially expressed in bulk tumor in human breast cancer (3). ASF1B mRNA was present at significantly increased quantities in TNBC tumor cells relative to normal mammary ductal cells. Analysis of human survival data revealed that expression of ASF1B in primary tumors of the breast was correlated with overall survival in patients with HER2+ type cancer, while within triple negative breast cancer, primary tumor expression of ASF1B was correlated with overall survival in patients with basal-like 2 subtype disease. ASF1B may be of relevance to initiation, maintenance or progression of triple negative breast cancers.