Prevention of spontaneous and chemically-induced carcinogenesis using activated carbon fiber adsorbent. I. Effect of the activated carbon fiber adsorbent ‘Aqualen’ on spontaneous carcinogenesis and life-span in mice Vladimir N. Anisimov a, *, Mark A. Zabezhinski a , Irina G. Popovich a , Alexander I. Lieberman b , Joseph L. Shmidt b a Laboratory of Experimental Tumors, N.N. Petrov Research Institute of Oncology, 68, Leningradskaya Str., Pesochny-2, St. Petersburg 189646, Russia b Aquaphor Corporation, 29, Pionerskaya Str., St. Petersburg 197042, Russia Received 23 June 1997; received in revised form 3 December 1997; accepted 3 December 1997 Abstract Female SHR mice were fed the activated carbon fiber adsorbent Aqualen  beginning at the age of 3 months through their life. Mice were fed Aqualen five times per week together with lab chow at a daily dose of 100 mg/kg b.w. The addition of Aqualen into food did not significantly influence the dynamics of body weight and the mean life-span of the animals. At the same time, the age at 90% mortality of mice was 4 months longer in the group exposed to Aqualen. There were no statistically significant differences in the incidence of all tumors and malignant tumors in the group of mice treated with Aqualen as compared with the control group. However, in the group of mice exposed to Aqualen, there was a 1.4 times reduction of the mean number of tumors per mouse. Feeding mice with the adsorbent led to a 4 months longer life-span in animals with any tumors and to a 5 months longer life-span in animals bearing malignant tumors (P  0.05). No carcinogenic effect of Aqualen was found. It could be supposed that Aqualen has some geroprotective and anticarcinogenic properties.  1998 Elsevier Science Ireland Ltd. Keywords: Fibrous adsorbent; Spontaneous tumors; Survival; Mice 1. Introduction At the present time enteroadsorbents are widely used in clinical practice for adsorption and excretion of different harmful compounds. Enteroadsorbents are successfully used in the treatment of allergy, bron- chial asthma, atherosclerosis and ischemia, hepatitis, inflammation and ulcers of the gastrointestinal tract and various endotoxicosis [1,2]. It was also shown that the use of enteroadsorbents can lead to an in- crease in animal life-span [3,4]. Enteroadsorbents cur- rently used in the medical practice include different materials with the most commonly used adsorbents made from granular and powdered activated carbons [1,2]. Cancer Letters 126 (1998) 23–28 0304-3835/98/$19.00  1998 Elsevier Science Ireland Ltd. All rights reserved PII S0304-3835(97)00518-1 * Corresponding author. Tel.: +7 812 4378607; fax: +7 812 4378947; e-mail: anisimov@anisimov.spb.ru