MAPK8 and breast cancer: For example, integrin α11 and platelet derived growth factor receptor beta (PDGFRβ)–positive CAFs can active the PDGFRβ-C-Jun N-terminal kinase 1 (JNK) signaling pathway to produce preinvasive matricellular protein tenascin C, thereby promoting breast cancer cell invasion; tumor metastasis and progression are associated with high integrin α11 and PDGFRβ expression in stromal cells of breast cancer [34].