FN1 and breast cancer: We observed that Rab27B expression level was positively correlated with the expression level of mesenchymal markers: Vimentin (rs = 0.289, P <0.001, n = 221, Spearman’s correlation analysis), Fibronectin (rs = 0.327, P < 0.001, n = 221, Spearman’s correlation analysis), and inversely correlated with epithelial markers: E-cadherin (rs = −0.226, P = 0.001, n = 221, Spearman’s correlation analysis), β-catenin (rs = −0.389, P < 0.001, n = 221, Spearman’s correlation analysis).These data illustrated that overexpression of Rab27B contributed to the EMT process in BC progression.