title: Thymidine kinase is expressed differently in transformed versus normal-cells - a novel test for malignancy.
abstract: Using a cytofluorometric assay, we studied the time course of thymidine kinase activity during the cell-cycle in logarithmically growing cells. Two different patterns were found. Many cells, including all strains of normal diploid fibroblasts, exhibited a transient stimulation of enzyme activity during early S-phase. On the contrary, virally transformed cells or lines derived from tumors also increased enzyme activity during G1/S, but kept this level until mitosis. In the latter case, the absolute enzyme activity was significantly higher during all phases of the cell-cycle than in normal cells. Beside its importance for the understanding of the transformed state, this phenomenon has obvious benefits for tumor diagnosis.
authors.affiliation: UNIV VIENNA,VIENNA BIOCTR,INST MOLEC BIOL,DR BOHRGASSE 9,A-1030 VIENNA,AUSTRIA.
authors.forename: M
authors.initials: M
authors.lastname: Hengstschlager
authors.forename: E
authors.initials: E
authors.lastname: Mullner
authors.forename: E
authors.initials: E
authors.lastname: Wawra