Axitinib did not induce apoptosis in endothelial cells in vitro and in fibrosarcoma and melanoma bearing mice [30], whereas sorafenib forced the expression of cleaved PARP-1 and caspase-3 in HUVECs and elevated the proportion of cells in the sub-G1 fraction [31,32]. Here, PARP1 is linked to fibrosarcoma.