due to the ectoenzymatic activities of the cells which include adenosinetriphosphatase and adenosinediphosphatase catalyzing the dephosphorylation of atp and adp , the effective levels of atp that inhibit the growth of human tumor cells in this system , which is widely claimed to predict the in vivo response of a tumor , are lower than the 5 to 20 microm which are exogenously supplied .
C0007634
cells
C0007595
growth of