Four central findings can be reported: (i) five upregulated and six downregulated miRNAs were revealed by integrative analyses of miRNA–mRNA sequencing; (ii) the MiR-146a directly targets NRP2, which is associated with tumor aggressiveness; (iii) MiR-146a inhibits SEMA3C-induced phosphorylation of p38 (p-p38) and invasion in suspension cells; (iv) high NPR2 is associated with worse prognosis in breast cancer patients. This evidence concerns the gene MAPK14 and breast cancer.