While there were no relevant CTGF levels in HNSCC mono-cultures, CTGF concentrations were found considerably enhanced when tumor cells were co-cultured with MSCs without treatment (p < 0.001 for UD-SCC-5-MSC2 co-culture, p < 0.0001 for all other comparisons) and after 8 Gy irradiation (p < 0.01 for UD-SCC-5-MSC2 co-culture, p < 0.0001 for all other comparisons) (Figure 7). This evidence concerns the gene CCN2 and head and neck squamous cell carcinoma.