TP53 and neoplasm: Animal studies further confirmed the high frequency of A>T transversions in AA-induced tumours, for instance in the forestomach epidermoid neoplastic cells from AA-exposed rats at codon 61 of the Ha-ras proto-oncogene [8], as well as in human p53 knock-in (Hupki) mouse embryonic fibroblasts exposed to AAI (Aristolochic Acid I) [31], [32].