Tumorigenesis, promotional phase

API. 1989. Short-term dermal tumorigenesis study of selected petroleum hydrocarbons in male CD-I mice. Initiation and promotion phases Final Report API 36-32643. American Petroleum Institute Washington DC. 

It is widely accepted that retinoids inhibit tumor growth and development, or the promotional phase of tumorigenesis (1J5) since it is well known that vitamin A plays a marked, as yet ill-defined, role in controlling the growth and differentiation of epidermis and epidermally-derived structures (16-18). Experimental evidence for this hypothesis rests primarily on the observation that conditions of hypervitaminosis A significantly inhibit tumor production even when initiated after application of the carcinogenic insult. Thus, 13-cis-retinoic acid inhibits the induction of transitional cell... 

Nitroxides suppressed tumorigenesis (Metodiewa etal. 1997). The medication of Tempicol-2 [4-hydroxy-4-(2-picolyl-2,2,6,6-tetramethylpiperidine-1-oxyl], a stable free radical, to rats bearing 3 day-old Yoshida sarcoma (promotion phase) induced both growth inhibition and apoptotic cell death, comparable to the effects of Tempace and Rutoxyl [ rutin/4 - acetamide-1 -hydroxyl-2,2,6,6-tetramethyl-piperidinium] under the same experimental conditions (Metodiewa et al. 1998). 

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