Clinical use of differentiating agents in cancer therapy.

Conceptually, the use of cytodifferentiation agents to suppress oncogenicity may prove most effective in long-term continuous treatment of patients whose tumors display some inherent expression of differentiated characteristics. This is the case in many pre-malignant lesions. The difficulty in evaluating the therapeutic role for HMBA, the retinoids, and cytosine arabinoside is oftentimes in separating in vivo cytotoxic from cytodifferentiation effects. Only with further studies will it be determined whether these and other cytodifferentiation agents are therapeutically useful and whether they can provide additional understanding of the processes of cellular transformation and differentiation with which they interact.