Chemotherapeutic Effects on Mammalian Tumor Cells. I. Modification of Leukemia L1210 Growth Kinetics and Karyotype With an Alkylating Agent

Abstract

A biologically and cytogenetically stable ascites line of Leukemia L1210 has been exposed to cyclophosphamide under certain defined conditions. Several sublines, developed from tumors recurrent after drug therapy, have been found to be substantially modified from the parent tumor with respect to virulence and karyotype. The findings suggest the tumor cells surviving treatment with cyclophosphamide exhibit a prolonged lag phase with gradual recovery of proliferative rate. Possible interpretations of these changes are discussed, and a mathematical model for the prediction of alteration of tumor growth by chemotherapy is presented.