Redifferentiation of cancer cells: bestatin, estradiol, and prostaglandin D2.

The induction of redifferentiation of cancer cells was studied. This was achievable with bestatin, especially in combination with sex hormones or prostaglandin D2, in murine undifferentiated mammary adenocarcinoma cells in vitro. Prostaglandin D2 also exerted a similar redifferentiating effect on M1 murine leukemia cells and a consecutive bestatin-hormone regimen was effective in endocrine tumors in man. Cancer redifferentiation may one day be developed into a clinical technique.