A tacit assumption underlying the search for anticancer drugs over the last 30 years has been that all cancer cells, irrespective of tissue origin, share certain common features that account for their unregulated growth and malignant properties. Accordingly, drugs effective against one type of tumor should be active against other classes of cancer. Unfortunately, this has not been the case. While many of the 40 FDA-approved cancer drugs are effective against certain leukemias and lymphomas (the so-called liquid tumors), their impact on the so-called solid malignancies (principally lung, breast, and colon) has been minimal. There are exceptions, however Cisplatin, introduced in 1978, has increased con- siderably the survival of patients with testicular cancer—a solid malignancy—but not with other classes of cancer.
These differential responses to chemotherapy of the liquid and solid malignancies, and among the different types of tumors within these classifications, demonstrate clearly that malignant tumors do not display ...
