Breast cancer affects women at relatively high frequency (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 RBPMS antisense RNA 1, RBPMS-AS1, when comparing primary tumors of the breast to the tissue of origin, the normal breast. RBPMS-AS1 mRNA was present at significantly

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... er quantities in tumors of the breast as compared to normal breast tissue. In a separate dataset, a coding RNA transcribed at the RBPMS locus was differentially expressed in primary tumors of the breast. Analysis of human survival data revealed that primary tumor expression of RBPMS-AS1 was correlated with overall survival in patients with luminal A and HER2+ subtype cancer, demonstrating a relationship between primary tumor expression of a differentially expressed gene and patient survival outcomes influenced by PAM50 molecular subtype. RBPMS-AS1 may be of relevance to initiation, maintenance or progression of cancers of the female breast.