| Abstract: | The differentiation-inducer activity of the aromatic retinoid etretin and of its ethyl ester etretinate (Tigazon) was tested on the human myelomonocytic leukemia cell lines HL-60 and U-937 and compared to that of retinoic acid. Whereas all-trans and 13-cis isomers of retinoic acid were equally potent in inducing the differentiation of about 80% of the cells of both lines, etretin and etretinate were found to be totally ineffective. These results indicate that neither compounds should be used in vivo in the treatment of acute myelocytic leukemia patients. |
