We performed an analysis of miRNA expression data to identify miRNAs that were differentially expressed (P ≤ 0.01, false discovery rate (FDR) ≤ 0%) between the mouse basal-type (C3(1)/Tag, p53fl/fl;MMTV-cre and BRCA1fl/fl;p53+/-;MMTV-cre) and luminal-type (MMTV-H-Ras, -Her2/neu, -c-Myc, -PymT, and -Wnt1, excluding the normal samples) mammary tumors. This evidence concerns the gene TP53 and breast cancer.