The FnBPs of S. aureus can significantly inhibit the expression of macrophage fibronectin, while activating the ERK elk1-c-fos, SRC JNK-c-Jun and p38 signaling pathways during the S. aureus infection, and the expression of the fnb gene can upregulate the c-fos and c-jun in squamous cell carcinoma cells [44,45]. Here, FOS is linked to squamous cell carcinoma.