FAP and central nervous system cancer: The synthetic small-molecule inhibitors of TGFbeta type I receptor (ALK-5 kinase) A8301 and A7701 [35] not only completely blocked the exogenous recombinant TGFbeta-1-mediated upregulation of FAP protein and FAP enzymatic activity in U87 glioma cells (Figure 6B,D), but also led to a significant decrease in the baseline level of FAP protein and FAP enzymatic activity in the cultured cells (Figure 6D).