Differential expression of histone cluster 1, H2bo 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 histone cluster 1, H2bo, HIST1H2BO, when comparing the tumor cells of patients with triple negative breast cancer to normal mammary ductal cells (2). HIST1H2BO was also differentially expressed in bulk tumor in human breast cancer (3). HIST1H2BO 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 HIST1H2BO in primary tumors of the breast was correlated with overall survival in patients with basal-like and normal-like subtype cancer, while within triple negative breast cancer, primary tumor expression of HIST1H2BO was correlated with overall survival in patients with luminal androgen receptor subtype disease. HIST1H2BO may be of relevance to initiation, maintenance or progression of triple negative breast cancers.