Possible inhibitory effects of promotion stage treatment with thymosin fraction 5 on N-butyl-N-(4-hydroxybutyl)nitrosamine-initiated urinary tract carcinogenesis in NON/Shi mice
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- Published online on: January 1, 1996 https://doi.org/10.3892/ijo.8.1.117
- Pages: 117-124
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Abstract
The modifying effects of thymosin fraction 5 (TF5), a dialyzable glycoprotein extract obtained from calf thymus, on second stage urinary tract carcinogenesis after N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) initiation were investigated in NON/Shi male mice. BBN was administered for 8 weeks and then TF5 was administered subcutaneously twice a week for 12 weeks. The incidence of urinary bladder carcinomas was decreased in the TF5 treatment group, but the malignancy of the renal pelvic carcinomas appeared to be enhanced. We repeated the experiment to obtain confirmatory evidence, but found no significant effect, although TF5 did stimulate the immune surveillance system. The reason why this discrepancy occurred might be related to the degree of hydronephrosis or the confounding influence of renal pelvic carcinomas.