Key advantages of the DiviTum® assay
DiviTum® is an innovative biomarker assay developed with the aim to monitor and predict treatment response in cancer therapy. The test measures the activity of the enzyme thymidine kinase-1 (TK) in blood serum or cell cultures. In normal cells, TK activity is hardly detectable, but in proliferating cells, its levels increase. Since the degree of TK activity is highly associated with the rate of cell proliferation, it is a particularly suitable biomarker for measuring tumor aggressiveness. Moreover, it offers several advantages over alternative techniques, e.g. rapid evaluation of response and avoids invasive testing.
How DiviTum® works
DiviTum® assay determines the enzymatic activity of TK in patient samples. During the assay procedure, thymidine is replaced by its synthetic analog bromodeoxyuridine (BrdU), which gets phosphorylated and then incorporated into a synthetic DNA strand fixated in each well of a 96-well ELISA immunosorbent titer-plate.
The extent of BrdU incorporation depends on the activity of TK present in the serum sample; the more TK activity in the sample, the more BrdU is incorporated into synthetic DNA strands in the titer-plate well. The synthetic BrdU is then detected with anti-BrdU specific antibodies using the well-known ELISA assay technique. The DiviTum® technology amplifies the signal, enabling the assay to measure thymidine kinase activity with high sensitivity.
Thymidine kinase phosphorylates the nucleoside analogue BrdU to BrdUMP. Additional enzymes further phosphorylate BrdUMP to BrdUTP.
BrdUTP is subsequently incorporated into a solid-phase DNA-strand. Incorporated BrdU is detected using an anti-BrdU monoclonal antibody conjugated to the signal generating enzyme alkaline phosphatase. The level amount of BrdU incorporated over time is proportional to the level of thymidine kinase activity in the sample.