Authors: Thompson, C. M., Gentry, R., Fitch, S., Lu, K., & Clewell, H. J.
In this evaluation, the authors review and update the mode of action (MOA) framework for nasal tumors, with particular emphasis on the studies published since 2006. In 2006 a published MOA for formaldehyde-induced nasal tumors in rats concluded that nasal tumors were most likely driven by cytotoxicity and regenerative cell proliferation, with possible contributions from direct genotoxicity. The most recent evaluation found that newer studies published since 2006, further underscore the involvement of cytotoxicity and regenerative cell proliferation and lend additional support for the use of mechanistic data for the derivation of toxicity criteria and/or scientifically supported approaches for low-dose extrapolation for the risk assessment of formaldehyde.