The blastomogenic activity of 2-aminoacetophenone (2-AAP)--one of the aromatic triptophan derivatives, found in the urine of leukemic patients, was studied on nonlineal Syrian hamsters, 2-AAP would induce the increased total incidence of tumors and raise the frequency of endocrine system tumors, especially adrenal adenomas. The results of the experiment indicate an insignificant blastomogenic activity of 2-AAP and correlate well with the results obtained on lineal mice.