The activation of Rho GTPase, that is, RhoA, Rac1, and Cdc42, is often involved in the migratory and metastatic biological behaviors of tumor cells.24 FLI‐1 can activate RhoA and Rac1, which correlates with breast cancer metastasis.15 The MDA‐MB231 cell line with a high expression of FLI‐1 has already been proved to possess mesenchymal properties and exhibit high expression of EMT‐associated genes.21, 22 These findings indicate that FLI‐1 might be related to the EMT program in the MDA‐MB231 cells. Here, CDC42 is linked to breast cancer.