Letters to the Editor

TUMOUR CELLS DISAGGREGATED IN COLLAGENASE

The concept of in vitro tests to predict for in vivo response to an antitumor agent is not a new idea. There are minimal requirements that these tests must possess in order to be both useful and practical. Each in vitro test must deal with a number of general technical problems including selection of the proper culture media, preparation of single cell suspensions, eliminating growth of unwanted cells, and selection of appropriate in vitro drug concentrations and exposure times. The specific types of in vitro predictive tests that have had in vitro-in vivo clinical correlation studies include tests relying on changes in cell morphology, tests relying on measurements of cell viability, in vitro tests based on primary site of action, in vitro tests measuring inhibition of cellular metabolism, measurements of radioactive precursor incorporation, measurements of labeling index of the tumor, and finally in vitro measurement of reproductive capability.