Immunohistochemical scoring of LAG-3 in conjunction with CD8 in the tumor microenvironment predicts response to immunotherapy in hepatocellular carcinoma

Abstract

IntroductionImmune checkpoint blockade (ICB) is a systemic therapeutic option for advanced hepatocellular carcinoma (HCC). However, low patient response rates necessitate the development of robust predictive biomarkers that identify individuals who will benefit from ICB. A 4-gene inflammatory signature, comprising CD8, PD-L1, LAG-3, and STAT1, was recently shown to be associated with a better overall response to ICB in various cancer types. Here, we examined whether tissue protein expression of CD8, PD-L1, LAG-3, and STAT1 predicts response to ICB in HCC.MethodsHCC samples from 191 Asian patients, comprising resection specimens from 124 patients (ICB-naïve) and pre-treatment specimens from 67 advanced HCC patients treated with ICB (ICB-treated), were analyzed for CD8, PD-L1, LAG-3, and STAT1 tissue expression using multiplex immunohistochemistry followed by statistical and survival analyses.ResultsImmunohistochemical and survival analyses of ICB-naïve samples showed that high LAG-3 expression was associated with shorter median progression-free survival (mPFS) and overall survival (mOS). Analysis of ICB-treated samples revealed that high proportions of LAG-3+ and LAG-3+CD8+ cells pre-treatment were most closely associated with longer mPFS and mOS. Using a log-likelihood model, adding the total LAG-3+ cell proportion to the total CD8+ cell proportion significantly increased the predictive values for mPFS and mOS, compared with the total CD8+ cell proportion alone. Moreover, levels of CD8 and STAT1, but not PD-L1, were significantly correlated with better responses to ICB. After analyzing viral-related and non-viral HCC samples separately, only the LAG3+CD8+ cell proportion was significantly associated with responses to ICB regardless of viral status.ConclusionImmunohistochemical scoring of pre-treatment levels of LAG-3 and CD8 in the tumor microenvironment may help predict ICB benefits in HCC patients. Furthermore, immunohistochemistry-based techniques offer the advantage of being readily translatable in the clinical setting.

Combinatorial blockade for cancer immunotherapy: targeting emerging immune checkpoint receptors

“…Studies of human cancers have shown that LAG-3 expression is abundant in TILs and associated with T cell dysfunction or insensitivity to PD-1 blockade. These include breast cancer ( 187 ), kidney renal clear cell carcinoma ( 188 ), melanoma ( 189 ), NSCLC ( 190 , 191 ), HCC ( 192 , 193 ), and B-cell lymphoma ( 194 ). LAG-3 expression in peripheral blood lymphocytes is also associated with resistance to ICI therapies in patients with melanoma and urothelial carcinoma ( 195 ).…”

Tumor Microenvironment Composition and Related Therapy in Hepatocellular Carcinoma

“…This indicates that the efficacy of ICB therapy in HCC can potentially be predicted by analyzing pre-treatment levels of LAG-3 and CD8 in the TME. 90 Neuropilins (NRPs) are the receptors of multiple proteins involved in pivotal signaling pathways related to HCC progression. NRP1 and NRP2 were reported as potential therapeutic targets and biomarkers for HCC.…”