CTNNB1 and hepatocellular carcinoma: Interestingly, at 8.3-weeks post-HDTVi, there was a significant increase in tumor burden in β-M-POU2F1 + βCD3 versus β-M-POU2F1 + IgG animals (Figure S19b–c), suggesting an immune-dependent role for POU2F1-mediated tumor regression in CTNNB1-mutated HCC.