Aberrant promoter methylation of PLK1-4 have been implicated in hepatocellular carcinoma [9], [10], while PLK2 promoter hypermethylation has been detected in hematologic malignancies such as acute myeloid leukemia and B-cell lymphoma, as well as in ovarian cancers [1], [8], [11]. This evidence concerns the gene PLK1 and hepatocellular carcinoma.