The expression levels of tRNA-derived small RNA, known as tsRNA, were interrogated in the following parental cell lines: MCF10A normal-like mammary epithelial cell, MCF7, MCF10AT1, MCF10CA1a, and MDA-MB-231 breast cancer cells. In addition, tsRNA expression was determined after shRNA-inhibition of RUNX1 in MCF10A cells or RUNX1 induction in MCF10CA1a cells. Overall design: Total RNA isolated from three biological replicates (subsequent passages) per cell line.