In this study, we studied feasibility of using cdc6 as biomarker for circulating tumor cell by examining the expression level of cdc6 in the PBMCs from health individuals, mononuclear cells from cord blood and a tumor cell line A549 with in situ hybridization, reverse transcript quantity polymerase chain reaction (RT‐qPCR) technique. This evidence concerns the gene CDC6 and neoplasm.