Evaluation of tumor cell heterogeneity based on response to chemotherapy

As the prototype for evaluation of tumor cell heterogeneity based on response to chemotherapy, several studies which examine the cells of the childhood leukemias are reviewed. These studies have examined the response to therapy of leukemic cells using a variety of clinical, in vivo and in vitro laboratory measures including: (1) response to combination chemotherapy in vivo as measured by numbers of residual leukemia cells observed within one to two weeks of initial therapy; (2) in vitro response to chemotherapy assessed in primary leukemic cell cultures exposed to antileukemic drugs.