[A short term test suitable for in vitro prediction of the drug sensitivity of human leukemias: a preliminary study on murine experimental neoplasms].

The present report provides information on the optimal assay conditions for evaluating chemosensitivity in vitro, as assessed by using murine leukemias and by correlating the in vitro results with the known chemosensitivity in vivo. The experiments were carried out with lymphocytic leukemias of DBA/2 origin, i.e.L1210 Cr and P388, maintained by weekly i.p. inoculation of 10(6) cells in histocompatible hybrid CD2F1 mice. Briefly, the assay involves in vitro incubation of leukemic cells with antitumor drugs for 1h at 37 degrees C and evaluation of drug-induced cell damage by adding to the cultured cells 125I-deoxyuridine at different times (3, 24, 48 and 72 hrs) after drug exposure. The results, expressed as percent inhibition of the isotope incorporation with respect to untreated controls, indicate that this assay may reflect the differential chemosensitivities exhibited in vivo by murine leukemias only on a 48-hr interval between drug treatment and 125IUdR uptake evaluation. These results suggest that a similar assay could be employed for predicting the chemosensitivity of human leukemias.