Transarterial chemoembolisation enhances programmed death-1 and programmed death-ligand 1 expression in hepatocellular carcinoma

Aims Immunotherapies represent a new alternative therapeutic approach for hepatocellular carcinomas (HCCs), and have shown promising results when used in combination therapy. The aim of this study was to evaluate the potential of transarterial chemoembolisation (TACE) to modulate programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) expression profiles in a cohort of surgically treated HCCs. Methods and results A total of 82 surgically treated HCCs from patients who had undergone (n = 32) or not undergone (n = 50) preoperative TACE were included in the study. Immunohistochemical expression of PD-1 and of PD-L1 were analysed and compared according to TACE treatment. Pretreatment biopsies, which were available for 30 cases (20 with TACE and 10 without), were similarly analysed. Follow-up data were retrieved from patients' charts. PD-1 expression (>= 1%) in intratumoral inflammatory cells (ICs) was observed in 46% of HCCs, and PD-L1 expression (>= 1%) in ICs and PD-L1 expression in tumour cells (TCs) were observed in 46% and 16% of HCCs, respectively. A low level of PD-1 expression (<1%) was associated with strong and diffuse glutamine synthetase overexpression (8% versus 27%, P = 0.024). HCCs from patients with TACE pretreatment showed significantly higher PD-L1 expression in TCs than those from patients without TACE pretreatment (2% versus 0.4%, P = 0.027). PD-1 expression in ICs and PD-L1 expression in both ICs and TCs were higher in TACE-resected tumours than in corresponding pre-TACE biopsies (respectively: 1.8% versus 8.1%, P = 0.034; 0.8% versus 7.1%, P = 0.032; and 0% versus 2.4%, P = 0.043). Conclusion Our results, showing increases in PD-1 expression and PD-L1 expression in HCCs following TACE, support the use of TACE in combination with immunotherapy in selected cases to optimise tumour response.