LRP4 mutations promote tumour progression and resistance to anti-PD-1 therapy in recurrent hepatocellular carcinoma

Background and aims: Hepatocellular carcinoma (HCC) recurrence is a major factor limiting long-time survival and the cause of most deaths in patients with HCC. However, molecular characterisation and potential therapeutic targets of recurrent HCC remain mostly unknown. Approach and results: We performed whole-exome sequencing (WES) in 63 matched primary and recurrent HCC tumours and combined the data with whole-genome sequencing (WGS) results in 43 paired samples from our previous study. Sanger sequencing was used to identify all low-density lipoprotein receptor-related protein 4 (LRP4) coding exons in 203 additional patients with recurrent HCC. We identified LRP4 somatic mutations in 7.8% (24/309) of recurrent tumours and only 0.97% (3/309) of primary tumours (P<0.001). Prognosis after the second liver resection was poorer in patients with an LRP4 mutation. Biofunctional investigations demonstrated that inactivating LRP4 mutations promoted tumour progression and immunosuppression. Mechanistically, mutated LRP4 reduced intratumoural conventional type 1 dendritic cell and CD8+ T cell infiltration by repressing CCL4 expression and secretion through activation of β-catenin signalling, resulting in resistance to anti-programmed cell death protein-1 (PD-1) therapy. Patients with recurrent HCC carrying an LRP4 mutation did not benefit from anti-PD-1 treatment after their second resection surgery. A β-catenin inhibitor reversed LRP4-induced resistance to anti-PD-1 therapy in humanised tumour-bearing mice. Conclusions: Our results identified novel LRP4 mutations important in recurrent HCC. Inactivating LRP4 mutations were associated with resistance to anti-PD-1 therapy and could be useful biomarkers for precision therapy in patients with recurrent HCC.