GSTA4 and hepatocellular carcinoma: Furthermore, for at least some of those which are elevated after sporidesmin exposure there is already evidence that beta-catenin is important in their regulation, genetic ablation of the beta-catenin encoding gene Ctnnb1 in human and murine leading to a loss of GSTM1, GSTA3 and GSTA4 expression [49], [50] while an activating mutation in beta-catenin in hepatocellular cancers leading to increased expression of GSTM and GSTA4 [54].