PLK1 and hepatocellular carcinoma: The three TSC2 null liver carcinoma cell lines SNU-886, SNU-878, and SNU-398 were uniformly sensitive to GSK461364, a PLK1 inhibitor, while in contrast the TSC1 null cell lines PEER and CAL-72 were not sensitive at all (Table 2) with IC50 values ranging from 5 to 33 nM.