Activated JNK has also been implicated in cell migration and invasion in human breast cancer, helps in epithelial–mesenchymal transition (EMT), and helps the activity of AP-1 transcription complex, which is a dimeric complex that includes members of the JUN proto-oncogene, FOS proto-oncogene, Musculoaponeurotic fibrosarcoma (MAF), and Activating Transcription Factor (ATF) protein families [9,10]. Here, FOS is linked to breast cancer.