CYP1A2 and neoplasm: In another study effects of low concentrations of AFB1 on the expression of TP53 and MDM2 (encoding a nuclear-localized E3 ubiquitin ligase that can promote tumour formation by targeting tumour suppressor proteins like TP53) were highlighted in BEAS-2B, a human bronchial epithelial cell line transfected with CYP1A2 (B-CMV1A2) and CYP3A4 (B3A4) cDNA.