Prognostic roles of pathology markers immunoexpression and clinical parameters in Hepatoblastoma

CD203c is expressed by human fetal hepatoblasts and distinguishes subsets of hepatoblastoma

Background & Aims

Hepatocytic cells found during prenatal development have unique features compared to their adult counterparts, and are believed to be the precursors of pediatric hepatoblastoma. The cell-surface phenotype of hepatoblasts and hepatoblastoma cell lines was evaluated to discover new markers of these cells and gain insight into the development of hepatocytic cells and the phenotypes and origins of hepatoblastoma.

Methods

Human midgestation livers and four pediatric hepatoblastoma cell lines were screened using flow cytometry. Expression of over 300 antigens was evaluated on hepatoblasts defined by their expression of CD326 (EpCAM) and CD14. Also analyzed were hematopoietic cells, expressing CD45, and liver sinusoidal-endothelial cells (LSECs), expressing CD14 but lacking CD45 expression. Select antigens were further examined by fluorescence immunomicroscopy of fetal liver sections. Antigen expression was also confirmed on cultured cells by both methods. Gene expression analysis by liver cells, 6 hepatoblastoma cell lines, and hepatoblastoma cells was performed. Immunohistochemistry was used to evaluate CD203c, CD326, and cytokeratin-19 expression on three hepatoblastoma tumors.

Results

Antibody screening identified many cell surface markers commonly or divergently expressed by hematopoietic cells, LSECs, and hepatoblasts. Thirteen novel markers expressed on fetal hepatoblasts were identified including ectonucleotide pyrophosphatase/phosphodiesterase family member 3 (ENPP-3/CD203c), which was found to be expressed by hepatoblasts with widespread expression in the parenchyma of the fetal liver. In culture CD203c⁺CD326⁺⁺ cells resembled hepatocytic cells with coexpression of albumin and cytokeratin-19 confirming a hepatoblast phenotype. CD203c expression declined rapidly in culture whereas the loss of CD326 was not as pronounced. CD203c and CD326 were co-expressed on a subset of hepatoblastoma cell lines and hepatoblastomas with an embryonal pattern.

Conclusions

CD203c is expressed on hepatoblasts and may play a role in purinergic signaling in the developing liver. Hepatoblastoma cell lines were found to consist of two broad phenotypes consisting of a cholangiocyte-like phenotype that expressed CD203c and CD326 and a hepatocyte-like phenotype with diminished expression of these markers. CD203c was expressed by some hepatoblastoma tumors and may represent a marker of a less differentiated embryonal component.

miR-126 in Extracellular Vesicles Derived from Hepatoblastoma Cells Promotes the Tumorigenesis of Hepatoblastoma through Inducing the Differentiation of BMSCs into Cancer Stem Cells

Background

Extracellular vesicles (EVs) can deliver miRNAs between cells and play a crucial role in hepatoblastoma progression. In this study, we explored the differentially expressed miRNAs related to tumor cell-derived EVs and the mechanism by which EVs regulate hepatoblastoma progression.

Methods

Bioinformatics analysis was performed to explore the differentially expressed miRNAs between the hepatoblastoma and adjacent normal tissues. TEM, NTA, and western blotting were conducted to identify EVs. The expression of miR-126-3p, miR-126-5p, miR-30b-3p, miR-30b-3p, SRY, IL-1α, IL-6, and TGF-β was detected by RT-qPCR. Immunofluorescence (IF) was used to analyze the expression of PKH67, and flow cytometry was applied to assess the ratio of CD44+ CD90+ CD133+ cells. ELISA was used to evaluate the levels of IL-6 and TGF-β. A xenograft mouse model was constructed to detect the function of EVs with downregulated miR-126. IHC was performed to calculate β-catenin levels in tumor tissues.

Results

miR-126 was upregulated in hepatoblastoma. EVs derived from hepatoblastoma cells significantly increased the ratio of CD44+ CD90+ CD133+ cells and increased the expression of IL-6, Oct4, SRY, and TGF-β in bone marrow mesenchymal stem cells (BMSCs), while EVs with downregulated miR-126 reversed these phenomena. miR-126 downregulation notably attenuated hepatoblastoma tumor growth and decreased the ratio of CD44+ CD90+ CD133+ cells and increased the expression of IL-6, Oct4, SRY, TGF-β, and β-catenin in tumor tissues of mice. Furthermore, EVs with downregulated miR-126 inhibited the differentiation of BMSCs into cancer stem cells.

Conclusions

Exosomal miR-126 derived from hepatoblastoma cells promoted the tumorigenesis of liver cancer through inducing the differentiation of BMSCs into cancer stem cells.

Immunohistochemical Expression Analysis of EpCAM in Hepatoblastomas

The epithelial cell adhesion molecule (EpCAM) is involved in oncogenesis of hepatoblastomas (HBs). Prior genomic profiling studies showed higher EpCAM expression and worse prognosis in HBs containing primitive histotypes, however, this has not been fully addressed from an immunohistochemical perspective. Our goal is to characterize differential EpCAM immunohistochemistry (EpCAM-IHC) among HBs histotypes. We retrieved 62 HBs from 52 patients. EpCAM-IHC was performed (anti-MOC-31, 1:50 dilution; Cell Marque Corporation, Rocklin, CA) and graded in histotypes using the immunoreactive score. The median age of patients was 2 years (range: 0.4 to 9 y) with a M:F ratio of 1.9. Outcome information was available in 38 patients (alive=30, alive with disease=3, and deceased=5) with median follow-up of 60 months (range: 2 to 171 mo). EpCAM-IHC showed notable overexpression (immunoreactive score >4) in embryonal (89%) and crowded fetal (74%) in contrast to glandular (33%), well-differentiated fetal (32%), and small cell undifferentiated/blastemal (3%) components. Mesenchymal elements were negative. In summary, EpCAM-IHC is helpful to distinguish between epithelial components as it is progressively lost in the transition from embryonal to crowded fetal and into well-differentiated fetal histotypes. Its preferential expression among primitive HBs might have therapeutic and prognostic implications. The significance of its largely negative expression in small cell undifferentiated/blastema is interesting despite its presumed immaturity, deserving further studies.

A new risk-stratification system for hepatoblastoma in children under six years old and the significance for prognosis evaluation-a 14-year retrospective study from a single center

BACKGROUND

This study explores and analyzes the clinical characteristics and prognostic factors of hepatoblastoma (HB) in children under 6 years old and establishes a new risk-stratification system for individualized therapy.

METHODS

The clinical data of 382 pediatric patients under 6 years old (231 males and 151 females) who had been diagnosed with HB by pathology between May 2005 and May 2019 were collected. By analyzing the risk factors influencing the survival rate of patients with HB, a new risk-stratification system was established, and it was compared with previous risk-stratification systems by a receiver operating characteristic (ROC) curve.

RESULTS

(1) According to a Kaplan-Meier survival analysis, the one-year, three-year, and five-year overall survival (OS) was 93.7, 84.0, and 73.9%, respectively, and the event-free survival (EFS) was 90.5, 79.2, and 67.5%, respectively. (2) The independent risk factors influencing prognosis in pediatric patients with HB were alpha-fetoprotein (AFP) < 100 ng/ml or > 1000 ng/ml (HR = 3.341, P = 0.005); platelet count > 400 × 10⁹/L (pooled hazard ratio [HR] = 2.123, P = 0.026); PRETEXT stage IV (HR = 4.026, P = 0.001); vascular involvement (HR = 2.178, P = 0.019); distant metastasis (HR = 2.634, P = 0.010);and multifocality (HR = 2.215, P = 0.012). (3) A new risk-stratification system was established and divided into three groups: low risk, moderate risk, and high risk. There were statistical differences among the three groups (P = 0.002). Compared with the previous risk-staging systems, there was no significant difference in the survival rate. Although the effect in the guiding therapy was the same, the area under the curve for the ROC curve was 0.835 (95% CI: 0.784-0.885) for the new stratification system.

CONCLUSION

This new risk-stratification system had a better predictive value for the prognosis of pediatric patients with HB than other stratification systems.

Upregulation of human endogenous retrovirus-K (HML-2) mRNAs in hepatoblastoma: Identification of potential new immunotherapeutic targets and biomarkers

PURPOSE

Hepatoblastoma is the most common liver malignancy in children. In order to advance therapy against hepatoblastoma, novel immunologic targets and biomarkers are needed. Our purpose in this investigation is to examine hepatoblastoma transcriptomes for the expression of a class of genomic elements known as Human Endogenous Retrovirus (HERVs). HERVs are abundant in the human genome and are biologically active elements that have been associated with multiple malignancies and proposed as immunologic targets in a subset of tumors. A sub-family of HERVs, HERV-K(HML-2) (HERV-K), have been shown to be tightly regulated in fetal development, making investigation of these elements in pediatric tumors paramount.

METHODS

We first created a HERVK-FASTA file utilizing 91 previously described HML-2 proviruses. We then concatenated the file onto the GRCh38.95 cDNA library from Ensembl. We used this reference database to evaluate existing RNA-seq data from 10 hepatoblastoma tumors and 3 normal liver controls (GEO accession ID: GSE8977575). Quantification and differential proviral expression analysis between hepatoblastoma and normal liver controls was performed using the pseudo-alignment program Salmon and DESeq2, respectively.

RESULTS

HERV-K mRNA was expressed in hepatoblastoma from multiple proviral loci. All expressed HERV-K proviral loci were upregulated in hepatoblastoma compared to normal liver controls. Five HERV-K proviruses (1q21.3, 3q27.2, 7q22.2, 12q24.33 and 17p13.1) were significantly differentially expressed (p-adjusted value <0.05, |log2 fold change| > 1.5) across conditions. The provirus at 17p13.1 had an approximately 300-fold increased expression in hepatoblastoma as compared to normal liver. This was in part due to the near absence of HERV-K mRNA at the 17p13.1 locus in fully differentiated liver samples.

CONCLUSIONS

Our investigation demonstrates that HERV-K is expressed from multiple loci in hepatoblastoma and that the expression is increased for several proviruses compared to normal liver controls. Our results suggest that HERV-K mRNA expression may be useful as a biomarker in hepatoblastoma, given the large differential expression profiles in hepatoblastoma, with very low mRNA levels in liver control samples.

Clinical risk stratification of children with SIOPEL high-risk hepatoblastoma in Taiwan

BACKGORUND

Hepatoblastoma is the most common primary liver malignancy in young children.

METHODS

To identify predictors of the clinical outcomes of hepatoblastoma, we retrospectively reviewed the medical records of 45 children with hepatoblastoma in the National Taiwan University Hospital from 1998 to 2018. All of the children were classified as high risk according to the pretreatment extent of disease (PRETEXT) staging system. The patients' clinical data (sex, age at diagnosis, PRETEXT status, presence of metastasis or tumor rupture, tumor pathologic type, and clinical outcomes) were analyzed.

RESULTS

A total of 45 children with high-risk hepatoblastoma were diagnosed at an average age of 3.2 years. The survival analysis showed that the event-free survival duration was significantly longer in patients aged ≤1.25 years at diagnosis than those >1.25 years (hazard ratio = 2.86, p = 0.036). The absence of initial tumor rupture was associated with longer event-free survival (hazard ratio = 2.74, p = 0.039). Diagnosis at age >1.25 years was correlated with the presence of multifocal liver tumors (p = 0.0002) and tumor rupture at diagnosis (p = 0.02). There was no significant difference in event-free survival between the groups classified as intermediate versus high risk according to the Children's Hepatic tumors International Collaboration hepatoblastoma stratification system (p = 0.13).

CONCLUSIONS

Diagnosis at ≤ 1.25 years of age and absence of initial tumor rupture were predictive of a good clinical prognosis in Taiwanese children with hepatoblastoma.

Intracellular localization of beta-catenin expression plays a possible prognostic role on the outcome of hepatoblastoma patients

PURPOSE

Wnt/Beta-catenin pathway plays an essential role in liver development and regeneration. Abnormal activation in this pathway leads to development of hepatoblastoma (HB). Although its importance has invoked attention, its prognostic role is debatable. We aimed to evaluate the significance of intracellular localization of beta-catenin (BC) expression in the outcome of hepatoblastoma patients.

METHODS

Medical records of HB patients between 2004 and 2018 were reviewed. Patients were grouped according to intracellular localization of BC expression by immunohistochemistry as being cytoplasmic or nuclear. Demographics, radiological images, PRETEXT classifications, vascular involvement, risk groups, chemotherapy responses, and survival rates were analyzed and compared between groups.

RESULTS

There were 41 patients. Thirteen patients were excluded for unavailability of records in four, negative/unclear BC expressions in seven. Cytoplasmic expression of BC was observed in 17 patients whereas 13 patients displayed nuclear expression. Demographics were similar in both groups. Cytoplasmic BC expression was associated with poor chemotherapy response (p = 0.001) and increased vascular involvement (p = 0.0162) requiring more extensive surgeries (p = 0.039).

CONCLUSION

Although the numbers are limited in our series, the intracellular localization of BC expression has been found to be a promising determining factor for hepatoblastoma prognosis. With larger patient series, more reliable results can be achieved.

Dysregulation of liver developmental microRNA contribute to hepatic carcinogenesis

BACKGROUND/PURPOSE

To investigate the role of microRNA (miRNA) dysregulation in liver cancer by assessing the miRNA profiles of human hepatic stem cells (HpSCs), marker-carrying human hepatoblastoma (HB) cells, and hepatocellular carcinoma (HCC) cells vs. those of fetal hepatocytes.

METHODS

We subjected human HCC and HB tumor specimens to immunohistochemical (IHC) staining for markers of HpSCs. We analyzed the miRNA patterns of HpSCs, HCC cells, HB cells, and fetal hepatocytes using microarray analysis, with confirmation via quantitative real-time polymerase chain reaction. The roles of the miRNAs in liver cancer stem cells (CSCs) were also elucidated.

RESULTS

The epithelial cell adhesion molecule (EpCAM) was the most prevalent HpSCs marker in human HB and HCC tumor cells and hepatoma cells. EpCAM-positive HB and HCC cells exhibited greater self-renewal and tumorigenicity than their EpCAM-negative counterparts or EpCAM-positive fetal hepatocytes. In EpCAM-positive fetal hepatocytes, miR-126 expression level increased with gestational age. The EpCAM-positive HB cells exhibited downregulation of miR-126 in comparison to EpCAM-positive fetal hepatocytes. An miR-126 mimic reduced sphere and colony formation in, and induced apoptosis of, HB cells. In comparison to EpCAM-positive fetal hepatocytes, EpCAM-positive HCC cells exhibited downregulation of miR-126, miR-144, and miR-451. Transfection of miR-126, miR-144, and miR-451 induced apoptosis of, and reduced sphere and colony formation in, HCC cells.

CONCLUSION

Dysregulation of liver developmental miRNAs, which exert a tumor suppressant effect, in EpCAM-positive HpSCs may contribute to liver carcinogenesis by promoting the transformation of HpSCs to CSCs of HB and HCC.

Prognostic Factors for Event-Free Survival in Pediatric Patients with Hepatoblastoma Based on the 2017 PRETEXT and CHIC-HS Systems

This study aimed to evaluate the prognostic value of variables used in the 2017 PRE-Treatment EXTent of tumor (PRETEXT) system and the Children's Hepatic tumors International Collaboration-Hepatoblastoma Stratification (CHIC-HS) system in pediatric patients with hepatoblastoma. A retrospective analysis of data from the pediatric hepatoblastoma registry of a tertiary referral center was conducted to evaluate the clinical and imaging variables (annotation factors) of the PRETEXT staging system. The primary outcome was event-free survival (EFS). Data from 84 patients (mean age: 2.9 ± 3.5 years) identified between 1998 and 2017 were included. Univariable Cox proportional hazards analysis revealed that PRETEXT annotation factors P (portal vein involvement), F (multifocality of tumor), and M (distant metastasis) showed a significant negative association with EFS. Multivariable Cox proportional hazard analysis showed that factor F was the strongest predictor (HR (hazard ratio), 2.908; 95% CI (confidence interval), 1.061-7.972; p = 0.038), whereas factor M showed borderline significance (HR, 2.416; 95% CI, 0.918-6.354; p = 0.074). The prediction model based on F and M (F + M) showed good performance to predict EFS (C-statistic, 0.734; 95% CI, 0.612-0.854). In conclusion, the PRETEXT annotation factor F was the strongest predictor of EFS, and the F + M model showed good performance to predict EFS in pediatric patients with hepatoblastoma.