While the molecular link between FAK, ERK1/2, and the osteogenic-differentiation-triggering Runt-related transcription factor 2 (RUNX2) could be demonstrated in human MSCs [54] (Figure 2), the FAK-ERK2 relevance for proliferation was shown in SiHa cells (squamous cell carcinoma cells derived from uterine tissue) by conducting experiments with selective FAK- and MAP-kinase-specific inhibitors [55]. Here, PTK2 is linked to squamous cell carcinoma.