RNA, including miRNA, was purified from mirrored human breast cancer tissue fresh frozen in liquid nitrogen using the QIAGEN miRNeasy Kit, or from sections of PAXgene Tissue-fixed, paraffin-embedded (PFPE) tissue using the PAXgene Tissue RNA/miRNA Kit. Shown is a scatterplot of CT values from different single miRNA-specific RT-qPCR assays using the QIAGEN miScript System: miR9, -10a, -10b, -29a, -103, -125b, -143, -145, -192 and miScript PCR controls RNUA1, RNU5A, RNU6B, SNORD25, SCARNA19, SNORA73A; R2: coefficient of determination.