SNAI1 is a key transcription factor in the EMT process, that is considered as the initial step of metastasis. The microRNAs(miRNAs) invovled in SNAI1-induced EMT may play important roles in regulating the process of metastasis. We used microarrays to establish the miRNAs both upregulated and downregulated in SNAI1-induced EMT process. Overall design: MCF-10A mammary epithelial cells were transfected with either SNAI1 (L) or a control vector (C) were harvested for RNA extraction and hybridization on Affymertix microarrays. 3 biological repetitions were done for microarray analysis.