In Vivo Immunostimulating Properties of Two Retinoids: Ro 10-9359 and Ro 13-6298

Vitamin A and some synthetic derivatives exhibit numerous activities; they have been recognized as an important factor in the differentiation of epithelial tissues (12,13); they possess an antiproliferative effect caused by a reduction of DNA synthesis (9); they can also prevent the development of tumors induced in vivo by chemical carcinogen or even reverse the malignant transformation (1, 10, 15). Many mechanisms could be involved in the antitumor activity of retinoids (2). Stimulation of the host immune system has been considered since retinoids are known to possess adjuvant-like properties (3, 6). However, it is not clear if immunological effect of retinoids play a role in the inhibition of tumor growth.