Identification of distinct tumor cell populations and key genetic mechanisms through single cell sequencing in hepatoblastoma

Abstract

Hepatoblastoma (HB) is the most common primary liver malignancy of childhood, and molecular investigations are limited and effective treatment options for chemoresistant disease are lacking. There is a knowledge gap in the investigation of key driver cells of HB in tumor. Here we show single cell ribonucleic acid sequencing (scRNAseq) analysis of human tumor, background liver, and patient derived xenograft (PDX) to demonstrate gene expression patterns within tumor and to identify intratumor cell subtype heterogeneity to define differing roles in pathogenesis based on intracellular signaling in pediatric HB. We have identified a driver tumor cell cluster in HB by genetic expression which can be examined to define disease mechanism and treatments. Identification of both critical mechanistic pathways combined with unique cell populations provide the basis for discovery and investigation of novel treatment strategies in vitro and in vivo.

The Cellular and Molecular Landscape of Synchronous Pediatric Sialoblastoma and Hepatoblastoma

“…After quality control, we obtained 21,450 single-cell transcriptomes from PT and AT samples of HB. Based on the canonical marker gene expression, 3,085 cells were annotated as tumor cells ( GPC3, EPCAM, AFP, ALB, DLK1 ), while 18,365 cells were designed as non-tumor cells ( Figures 4D, E ) ( 44 , 45 ). We further confirmed the identity of tumor cells by evaluation of inferred segmental chromosomal alterations.…”

Surgical Pathology Diagnostic Pitfalls of Hepatoblastoma

“…In addition, germline and somatic mutations compound developmental factors, such as low birth weight and prematurity, to influence HB induction and growth. 1,6,8,26,27 Mutations implicated in the development of HB often involve the Wnt signaling pathway, more specifically, relating to the beta-catenin protein, a transcriptional cofactor. 10,11,28 Wnt signaling is intrinsic to embryonic development, promoting organized cellular proliferation and differentiation.…”

“…In addition, germline and somatic mutations compound developmental factors, such as low birth weight and prematurity, to influence HB induction and growth. 1 , 6 , 8 , 26 , 27 …”

“…For example, neoplastic cells may differentiate along a pathway reminiscent of cholangiocytes, resulting in bile duct-like structures within the tumor mass. 12 , 18 , 27 This is particularly problematic following pre-operative chemotherapy, which can induce a ductular reaction in the periphery of the tumor. 12 In slightly older children of over 5 years, tumors may exhibit intermediate features between hepatoblasts and hepatocytes.…”

“… 5 , 19 The balance is tipped towards HB in the presence of glutamine synthetase and cyclin D1 positivity, and certain genetic markers are more commonly encountered, such as chromosome 1p abnormalities and trisomy of chromosomes 2, 20, and 8. 5 , 19 , 25 , 27 However, as with immunohistochemical staining, this distinction is not definitive, and the same genetic markers are highlighted in up to 40% of pediatric HCC. 5 …”