Phenotypic Characteristics of the Tumour Microenvironment in Primary and Secondary Hepatocellular Carcinoma

Abstract

(1) Background: The intra-tumoural heterogeneity (ITH) of hepatocellular carcinoma (HCC) and its microenvironment (TME) across primary and secondary disease is poorly characterised. (2) Methods: Intra-tumoural (IT) and peri-tumoural (PT) staining of matched primary and secondary samples was conducted to evaluate the distribution of CD4+/FOXP3+ and CD8+/PD1+ T-cells. Samples underwent PD-L1/2 immunostaining, tumour mutational burden (TMB) evaluation, and high-resolution T-cell receptor (TCR) sequencing to derive T-cell clonality and targeted transcriptomics. (3) Results: We analysed 24 samples from matched primary (n = 11) and secondary (n = 13; 5 synchronous, 6 metachronous) deposits, 11 being extrahepatic (84.6%). IT CD8+ density was lower than PT in both primary (p = 0.005) and secondary deposits (p = 0.01), consistent with immune exclusion. PD-L1+ tumours displayed higher IT and PT CD8+/PD1+ cell density compared to PD-L1- (p < 0.05), and primary IT infiltrate was enriched in CD4+/FOXP3+ cells, compared to PT regions (p = 0.004). TCR-sequencing demonstrated enrichment of the top T-cell clonotype in secondary versus primary HCC (p = 0.02), without differences in overall productive clonality (p = 0.35). TMB was similar across primary versus secondary HCC (p = 0.95). While directed gene set analysis demonstrated the uniformity of transcriptional signatures of individual immune cell types, secondary deposits demonstrated higher COLEC12 (p = 0.004), CCL26 (p = 0.02), CD1E (p = 0.02) and CD36 (p = 0.03) expression with downregulation of CXCL1 (p = 0.03), suggesting differential regulation of innate immunity. (4) Conclusion: Immune exclusion is a defining feature of the HCC TME. Despite evidence of homogeneity in somatic TMB, secondary HCC is characterised by the expansion of a distinct T-cell clonotype and differential regulation of innate immune pathways.

Patterns and outcomes of subsequent therapy after immune checkpoint inhibitor discontinuation in HCC

“…Data were not collected on patterns of disease failure with each line of therapy, which would be of interest particularly with regard to emerging work investigating the immune infiltrate in metastases compared with the primary site giving insight into patterns of immune escape. [37] It should be noted that most patients had received sorafenib in the first-line setting; this did not affect the survival benefit from subsequent TKIs and supports the findings of the post hoc analyses of the RESORCE, CELESTIAL, and REFLECT studies that illustrate additive survival benefit with sequential TKIs owing to their nonredundant molecular targets. [13][14][15] There is a complex interplay between angiogenesis and the immune response, and much research has addressed the role of anti-angiogenics in enhancing the response to immunotherapy.…”

Cell Death in Hepatocellular Carcinoma: Pathogenesis and Therapeutic Opportunities

“…As heterogeneity of tumor ecosystem cells could also impact the patient’s therapeutic response, TME reprogramming has been intensely explored in recent years. Higher transcriptomic and phenotypic diversity has been described in TME reprogramming, and was associated with poorer overall patient survival [ 79 , 82 ].…”

Patients with polyclonal hepatocellular carcinoma are at a high risk of early recurrence and have a poor recurrence-free survival period

“…The tumor mutation burden (TMB) has been reported as the total number of non-synonymous variants per tumor genomic region [ 22 ]. The TMB level of HCC is relatively low, compared with other types of solid cancers [ 23 ]. The TMB score of the presently reported cohort was also not high (median TMB = 6.7), and no difference in TMB was observed between the poly-CC (median 6.7; range 2.5–12.7) and the mono-CC (median 6.7; range 4.2–12.6) groups.…”