Open AccessT25: A Simplified Carcinogenic Potency Index: Description of the System and Study of Correlations between Carcinogenic Potency and Species/Site Specificity and Mutagenicity
Author(s) -
Dybing Erik,
Sanner Tore,
Roelfzema Henk,
Kroese Dinant,
Tennant Raymond W.
Publication year - 1997
Publication title -
pharmacology & toxicology
Language(s) - English
Resource type - Journals
eISSN - 1600-0773
pISSN - 0901-9928
DOI - 10.1111/j.1600-0773.1997.tb01973.x
Subject(s) - carcinogen , potency , toxicology , chemistry , biology , in vitro , biochemistry
A simplified carcinogenic potency index, the T25, is proposed as a practical method for the inclusion of potency considerations in carcinogen classification systems. The T25 is the chronic daily dose in mg per kg bodyweight which will give 25% of the animals tumours at a specific tissue site, after correction for spontaneous incidence, within the standard life span of that species. Calculated T25 values of a set of 113 US National Cancer Institute/National Toxicology Program (NC/NTP) carcinogens showed excellent correlation (correlation coefficient 0.96, P<0.0001) with the carcinogenic potency index TD50 of Peto et al. (1984). The mean of T25 values for 51 transspecies, multiple common site NCI/NTP carcinogens were 10‐fold lower than those for 62 NCI/NTP single species, single site carcinogens. For these 113 carcinogens, the mean T25 values were approximately 3‐fold lower for agents that were also mutagenic in Salmonella compared to the non‐mutagenic agents.