The results of mass spectrometry-based quantitative phosphoproteomic profiling, immunofluorescence, and western blot showed that the inhibitory effect of SFN on breast cancer cell migration and invasion is attributed to the reduction of actin stress fiber formation and its associated protein expression, including paxillin, FAK, IQGAP1, ROCK, and PAK2. The gene discussed is PXN; the disease is breast cancer.