This week, we are pleased to welcome Dr. Kevin P. Cross, Instem’s Principal Investigator with U.S. FDA Collaborations and VP of Product Engineering and Production, as a guest contributor to the blog.

We were happy to contribute to a recent publication titled “Use of the Bacterial Reverse Mutation Assay to Predict Carcinogenicity of N-Nitrosamines”.1

N-Nitrosamines (NAs) are a cohort of concern in the ICH M7 guideline2 and have recently come under increased regulatory scrutiny, mainly because of their potential to be highly potent mutagenic carcinogens in rodent bioassays.

This publication performed an analysis of public databases with both bacterial reverse mutation (Ames) assay and rodent carcinogenicity data, and the sensitivity of the Ames assay to predict the carcinogenic outcome was examined. The paper demonstrated that the Ames assay conducted under OECD 471 guidelines is highly sensitive for detecting the carcinogenic hazards of NAs.   

Please feel free to contact me (Kevin Cross; if you would like any additional information.


  1. Alejandra Trejo-Martin et al., 2022, Use of the Bacterial Reverse Mutation Assay to Predict Carcinogenicity of N-Nitrosamines, Regulatory Toxicology and Pharmacology, 105247.
  2. ICH, M7 (R1) Assessment and control of DNA reactive (mutagenic) impurities in pharmaceuticals to limit potential carcinogenic risk, European Medicines Agency, 2017.

Published by Glenn Myatt

Glenn J. Myatt is the co-founder of Leadscope and currently Senior Vice President, In Silico & Translational Science Solutions at Instem with over 30 years’ experience in computational chemistry/toxicology. He holds a Bachelor of Science degree in Computing, a Master of Science degree in Artificial Intelligence and a Ph.D. in Chemoinformatics. He has published 37 papers, 11 book chapters and three books.