Continued progress in developing the Pig-a gene mutation assay

The Pig-a assay has shown promise as a regulatory assay for evaluating in vivo gene mutation. A recent International Workshop on Genotoxicity Testing workgroup discussed the state of the assay and identified several knowledge gaps in assay development. This Mutagenesis Special Topic includes a collection of reports that addresses some of these knowledge gaps, including identifying the mutations responsible for the Pig-a mutant phenotype, the effect of sex on the response, probing the robustness of the assay and expanding the number of agents tested in the assay, especially agents expected to yield negative responses.