Immuno-Activated, Highly Expressing PD-1 Phenotype in Hepatocellular Carcinoma Is Associated with a Lower Recurrence Rate

Abstract

Introduction: Curative treatments in early-stage hepatocellular carcinoma (HCC) are limited by high recurrence rates, and targeted therapies against HCC are rare. Tumour microenvironment (TME) plays a crucial role. One strategy is the expression of programmed cell death receptor 1 ligand (PD-L1), whose receptor PD-1 is expressed on activated T cells. The use of immune checkpoint inhibitors (ICIs) has shown antitumour activity. In HCC, ICIs are proposed as a possible first- and second-line therapy. The expression of PD-1 and PD-L1 in the TME is of prognostic importance and can predict response to ICIs. Our study aimed to investigate the impact of intratumoural PD-1 and PD-L1 expression on HCC recurrence and its relation to cancer-immune phenotypes.

Methods: Immunohistochemical staining was performed on archival tissue from 93 HCC, using the antibodies NAT105 (PD-1) and Ventana SP263 (PD-L1). Tumours were classified as immunologically active, excluded, or deserted. PD-1 and PD-L1 immunoreactivity was evaluated as the proportion of positive immune cells compared to the total immune cells (0%, <1%, and >1%).

Results: HCC with PD-1 expression in >1% of immune cells had a significantly lower recurrence rate than tumours with <1% PD-1 expression (78%; 38/49, p = 0.027). HCC classified as immune active was also enriched for PD-1 expression >1% (77%; 48/62). Tumours with both characteristics had a significantly lower recurrence rate (p = 0.039).

Conclusion: PD-1 expression on immune cells is associated with a lower recurrence rate in HCC, suggesting a role in HCC recurrence. The therapeutic use of adjuvant anti-PD-1 antibodies should thus be viewed critically and investigated further.

Keywords: Hepatocellular carcinoma; Immune-phenotype; PD-1.

Fig. 1.

Histological staining of PD-1 expression in lymphocytes. Areas of interest are highlighted with red arrows or circled areas. a Negative for PD-1. b Low (<1%). c Immune excluded. d High (≥1%). e Immune activated (magnification (a–c) ×10, (d, e) ×20).

Fig. 2.

Correlation of PD-1 expression in lymphocytes with cirrhosis and immune phenotype in relation to recurrence. a Significant lower recurrence rate in PD-1_High, p = 0.027. b PD-1_High and cirrhosis p = 0.003. c PD-1 and non-cirrhotic p > 0.999. d PD-1_High and immune activated expression p = 0.704. e PD-1_High and immune excluded expression p = 0.086.

Fig. 3.

a Recurrence free survival in high and low expressed PD-1 on lymphocytes. Kaplan-Meier for recurrence free survival (RFS). For each patient not known to have died, RFS is censored at the time of last date known to be alive; Log-rank, one-sided p. b Overall survival in high and low expressed PD-1 on lymphocytes. Kaplan-Meier for overall survival (OS). For each patient not known to have died, OS is censored at the time of last date known to be alive; Log-rank, one-sided p.

Fig. 4.

Correlation of combinations of PD-1 expression in lymphocytes cirrhosis and immune phenotype in relation to recurrence. a High PD-1 expression and cirrhosis compared to the rest (p = 0.02). b High PD-1 expression and immune activated phenotype compared to the rest (p = 0.039). c High PD-1 expression and cirrhosis and immune activated phenotype compared to the rest (p = 0.044).