FAP and cancer: Concerning potential phenotypical alterations, RT seemed to increase the expression levels of FAP (fibroblast activation protein), MMP2 (matrix metalloproteinase 2), and ACTA2 (alpha smooth muscle actin) as well as TAGLN (transgelin), indicating an activated, more reactive MSC phenotype or potential differentiation toward a cancer-associated fibroblast/myofibroblast-like phenotype (Figure 3D), although induced expressions were not significant, and no significant alterations concerning classical MSC marker expressions could be found (not shown).