MA and EA were negative in bacterial mutation tests (Florin et al. 1980; Suh et al. 2018), but at cytotoxic concentrations MA and EA were positive in mammalian cell tests, the in vitro micronucleus test in CHO cells (Kirpnick et al. 2005) and the mouse lymphoma TK+/− test (Suh et al. 2018). This evidence concerns the gene TKT and lymphoma.