Evaluation of the sensitivity and specificity of in vivo erythrocyte micronucleus and transgenic rodent gene mutation tests to detect rodent carcinogens

Abstract

Sensitivity and/or specificity of the in vivo erythrocyte micronucleus (MN) and transgenic rodent mutation (TGR) tests to detect rodent carcinogens and non-carcinogens were investigated. The Carcinogenicity and Genotoxicity eXperience (CGX) dataset created by Kirkland et al. was used for the carcinogenicity and in vitro genotoxicity data, i.e., Ames and chromosome aberration (CA) tests. Broad literature surveys were conducted to gather in vivo MN or TGR test data to add to the CGX dataset. Genotoxicity data in vitro were also updated slightly. Data on 379 chemicals (293 carcinogens and 86 non-carcinogens) were available for the in vivo MN test; sensitivity, specificity or concordances were calculated as 41.0%, 60.5% or 45.4%, respectively. For the TGR test, data on 80 chemicals (76 carcinogens and 4 non-carcinogens) were available; sensitivity was calculated as 72.4%. Based on the recent guidance on genotoxicity testing strategies, performance (sensitivity/specificity) of the following combinations was calculated; Ames+in vivo MN (68.7%/45.3%), Ames+TGR (83.8%/not calculated (nc)), Ames+in vitro CA+in vivo MN (80.8%/21.3%), Ames+in vitro CA+TGR (89.1%/nc), Ames+in vivo MN+TGR (87.5%/nc), Ames+in vitro CA+in vivo MN+TGR (89.3%/nc). Relatively good balance in performance was shown by the Ames+in vivo MN in comparison with Ames+in vitro CA (74.3%/37.5%). Ames+TGR and Ames+in vivo MN+TGR gave even higher sensitivity, but the specificity could not be calculated (too few TGR data on non-carcinogens). This indicates that in vivo MN and TGR tests are both useful as in vivo tests to detect rodent carcinogens.

Combinations of genotoxic tests for the evaluation of group 1 IARC carcinogens

“…As this study is only restricted to group 1 IARC carcinogens, hence higher sensitivity was obtained. The sensitivity of in vivo MN tests in this study was higher as compared to studies from Morita et al (2016) (41%) and Lambert, Singer, Boucher, and Douglas (2005) (66%), and slightly lower than Kirkland et al (2005) (78.7%). The sensitivity of in vivo CA was much higher in this study than Kim and Margolin (1999) (43%), and Lambert et al (2008) (69%).…”

“…In our study, the sensitivity of Ames + in vivo MN was 77.9%. Lower sensitivity (68.7%) was observed for Ames + in vivo MN byMorita et al (2016). Higher sensitivity was also observed in the combination of Ames + in vivo CA (84%) and in vivo MN + in vivo CA (88.6%).…”

“…With the advancement in the field of genotoxicology, several tests were added to the existing list and an approach is being made to find good combinations of test, which provide better sensitivity as well as specificity. Studies have also shown that different combinations of Ames, in vivo MN, in vivo CA and CMT assay increases the sensitivity of carcinogen detection (Kang et al, ; Kim & Margolin, ; Morita et al, ; Sasaki et al, ). The combination of the Ames test and in vivo MN test was found effective in the detection of human genotoxic carcinogen (Shelby & Zeiger, ).…”

“…It is easy, reliable and has been employed for laboratory assays of genotoxicity of many compounds (Morita et al, 1997). Traditionally the MN test in rodent bone marrow or peripheral blood lymphocyte has been widely used to detect in vivo chromosomal damage (Benigni, Bossa, Tcheremenskaia, Battistelli, & Crettaz, 2012;Morita et al, 2016;Sasaki et al, 2000;Soeteman-Hernández, Johnson, & Slob, 2016). However, these tests have been reported negative for several carcinogenic agents (Sasaki et al, 2000;Zeiger, 1998).…”

Differentiation of Aneugens and Clastogens in the In Vitro Micronucleus Test by Kinetochore Scoring Using Automated Image Analysis

“…MN are small, extra‐nuclear chromatin bodies surrounded by a nuclear envelope, which are not incorporated into the nucleus of a daughter cell after nuclear division (Fenech and Morley, ; Fenech, ; Vanhauwaert et al, ; Mishima, ). MN are indicative of chromosome or genome mutations and are commonly observed in cancer development (Kirsch‐Volders et al, ; Bolognesi et al, ; Morita et al, ). Thus, MN induction is a well‐established genotoxicological endpoint during drug safety assessment.…”