Effects of neoadjuvant chemotherapy on hepatoblastoma: a morphologic and immunohistochemical study

Hepatoblastoma: Comprehensive Review With Recent Updates

Hepatoblastoma (HB), the most common primary malignant liver tumor of childhood, demonstrates remarkable histologic heterogeneity and can be classified into epithelial or mixed epithelial-mesenchymal subtypes. This review summarizes updates in histologic classification, molecular signatures, staging, and risk stratification of HB. The Children's Hepatic tumors International Collaboration represents an international effort to standardize the study of rare pediatric liver tumors; emphasis continues to remain on improving risk stratification by a combination of clinical, histologic, and molecular features to tailor treatment in a bid to reduce toxicity while maintaining or improving efficacy. Pure fetal HB is cured by complete resection without the need for adjuvant chemotherapy. Malignant rhabdoid tumors have been parsed out from small cell undifferentiated HBs by negative INI-1 staining on immunohistochemistry; these tumors require a distinct and more aggressive chemotherapeutic regimen. The significance of recently characterized "blastema" component in HB remains to be elucidated. Hepatocellular neoplasm, not otherwise specified, is a provisional diagnostic category for tumors exhibiting either intermediate or a combination of both HB and hepatocellular carcinoma histologic features. The Children's Hepatic tumors International Collaboration risk stratification algorithm includes age as an important discriminator of risk, in addition to AFP, metastasis, and PreTreatment EXTent of disease stage and its annotations.

Image-Guided Biopsy for the Diagnosis and Molecular Profiling of Hepatoblastoma

INTRODUCTION

Studies on the use of image-guided percutaneous biopsy for hepatoblastoma (HB), and recommendations put forth by the pediatric hepatic international tumor trial (PHITT), are limited. It is unknown if sufficient tissue can be obtained for trial enrollment as well as molecular profiling, which will likely play a key role in informing future treatment strategies.

METHODS AND MATERIALS

Patients with HB who underwent percutaneous biopsy at initial diagnosis in interventional radiology (IR) over a 12-year period at a single center were included. Patient demographics, pretreatment extent of disease (PRETEXT) stage, tumor size, and procedure details were collected. Pathology reports and tumor genomic analysis, when performed, were assessed for specimen adequacy. Post-procedure records were assessed for hemoperitoneum.

RESULTS

A total of 33 percutaneous biopsies were performed on 32 patients [17 female; median age 1.3 years (IQR: 0.7-2.5 years); median weight 10.5 kg (IQR: 7.4-12.7 kg)]. Most (n = 27) had a single liver lesion, and most (n = 18) were PRETEXT II. A total of 15 were positive for at least one annotation factor. Median longest tumor axis was 9.3 cm (IQR: 5.0-13.5 cm). A total of 16 patients had concurrent non-targeted liver biopsy, per PHITT recommendations. An 18-gauge instrument was most commonly used (n = 24, 73%) with a median of 8 cores (IQR: 6-12) obtained. There were no instances of hemoperitoneum. Tissue was adequate for histologic diagnosis in 97% (n = 32), with histologic subtyping obtained in 94% (30/32). When available (n = 29), comparison with the subsequent surgical resection specimen showed subtype concordance in 15 (52%) patients and minor variations secondary to sampling or treatment effect in 14 patients. Molecular profiling was completed on 21/21 specimens (100%), with 19/21 (90%) showing potentially clinically significant variants, most commonly in CTNNB1 (16/21).

CONCLUSION

In this single-center study, percutaneous biopsy resulted in no serious adverse events, a high rate of diagnosis, and successful subtyping and molecular characterization of HB.

"Update on pediatric primary liver tumors"

Liver masses are common in children, however primary malignant neoplasms are rare, representing only 1% of all pediatric cancers. Hepatocellular neoplasms are the most common primary liver malignancies and hepatoblastoma (HB) is the most frequently diagnosed. The incidence of HB, which is increasing, is approximately of 2 cases per million in the United States, followed by hepatocellular carcinoma (HCC). Pediatric primary liver tumors of mesenchymal origin are less common, except for benign vascular tumors (hemangiomas). Malignant mesenchymal neoplasms represent approximately 10-15% of all, the most common being embryonal sarcoma and malignant rhabdoid tumor. Malignant vascular tumors are rare, but epithelioid hemangioendothelioma (EHE) and angiosarcoma can be seen in children. The development and adoption of consensus diagnostic, therapeutic and risk-stratifying approaches for pediatric patients with malignant liver tumors has been historically challenged by their rarity and by their diverse clinical and histological appearance. On-going collaborative efforts of international consortia including the Children's Oncology Group (COG) in North America, the German Society of Paediatric Oncology and Haematology (GPOH), the Societe Internationale d' Oncologie Pediatrique Liver Tumor Study Group (SIOPEL) in Europe and the Japanese Liver Tumor group (JPLT), have made significant contributions to understanding the clinical and histopathological features, as well as the underlying biology of pediatric liver tumors, in particular HB. A new classification of pediatric liver tumors drafted at the international consensus meeting held in Los Angeles, has been incorporated in the recent WHO classification and is currently used by the PHITT (Paediatric Hepatic Malignancy International Tumour Trial) and other therapeutic protocols. This manuscript provides an overview of salient diagnostic features and updates in classification and molecular characterization for the most common pediatric primary liver neoplasms. It also includes a brief overview of other less common but relevant tumors, which should be considered in the differential diagnosis.

Impact of treatment on the prognosis of childhood in hepatoblastoma: A SEER based analysis

Background

The prognosis of patients with hepatoblastoma has been unsatisfactory. This study analyzed the effects of different treatment methods on cancer-specific survival (CSS) in children with hepatoblastoma.

Method

From 2000 to 2018, patients with hepatoblastoma were included in the Surveillance, Epidemiology, and End Results (SEER) database. CSS was estimated using the Kaplan-Meier method. Cox regression analysis assessed prognostic factors. The predictive models were validated using the concordance index (C-index), calibration curve and receiver operating characteristic (ROC) curve.

Result

Of the 785 included patients, 730 (93.0 %) underwent chemotherapy, 516 (65.7 %) underwent liver tumour resection and 129 (16.4 %) underwent liver transplantation. Both chemotherapy and surgery could significantly improve the CSS rate (all p < 0.001). However, there was no difference in CSS rate between the two surgical methods (liver tumour resection and liver transplantation) (p = 0.613). Further subgroup analysis revealed that children who underwent liver tumour resection or liver transplantation based on chemotherapy (all p > 0.05) had a similar prognosis. Multivariate analysis revealed that age (p = 0.003), race (p = 0.001), operative method (p < 0.001), chemotherapy (p < 0.001), distant metastasis (p < 0.001) and tumour size (p < 0.001) were independent factors related to CSS. The C-index of the new nomogram was 0.759, and its consistency was good. The ROC curves verified that the nomogram had a better prediction ability for 1-, 3- and 5-year CSS rates.

Conclusion

In children with hepatoblastoma, there was no statistically significant difference in CSS between chemotherapy combined with liver transplantation and liver tumour resection. The nomogram we constructed demonstrated satisfactory CSS prediction ability.

Pediatric Hepatoblastoma After Neoadjuvant Chemotherapy: Diagnostic Performance of MR in Staging POSTTEXT and Vascular Involvement

BACKGROUND

The assessment of resectability after neoadjuvant chemotherapy of hepatoblastoma is dependent on Post-Treatment EXTENT of Disease (POSTTEXT) staging and its annotation factors P (portal venous involvement) and V (hepatic venous/inferior vena cava [IVC] involvement), but MR performance in assessing them remains unclear.

PURPOSE

To assess the diagnostic performance of contrast-enhanced MR imaging for preoperative POSTTEXT staging and diagnosing vascular involvement in terms of annotation factors P and V in pediatric hepatoblastoma following neoadjuvant chemotherapy.

STUDY TYPE

Retrospective.

SUBJECTS

Thirty-five consecutive patients (17 males, median age, 24 months; age range, 6-98 months) with proven hepatoblastoma underwent preoperative MR imaging following neoadjuvant chemotherapy.

FIELD STRENGTH/SEQUENCE

3.0 T; T2-weighted imaging (T2WI), T2WI with fat suppression, diffusion weighted imaging, radial stack-of-the-star/Cartesian 3D Dixon T1-weighted gradient echo imaging.

ASSESSMENT

Three radiologists independently assessed the POSTTEXT stages and annotation factors P and V based on the 2017 PRE/POSTTEXT system. The sensitivities and specificities were calculated for 1) diagnosing each POSTTEXT stage; 2) discrimination of stages III and IV (advanced) from those stages I and II (non-advanced) hepatoblastomas; and 3) annotation factors P and V. The combination of pathologic findings and surgical records served as the reference standard.

STATISTICAL TESTS

Sensitivity, specificity, Fleiss kappa test.

RESULTS

The sensitivity and specificity ranges for discriminating advanced from non-advanced hepatoblastomas were 73.3%-80.0% and 80.0%-90.0%, respectively. For annotation factor P, they were 66.7%-100.0% and 90.6%, respectively. For factor V, they were 75.0% and 67.7%-83.9%, respectively. There was excellent, substantial, and moderate agreement on POSTTEXT staging (Fleiss kappa = 0.82), factors P (Fleiss kappa = 0.64), and factors V (Fleiss kappa = 0.60), respectively.

DATA CONCLUSION

MR POSTTEXT provides reliable discrimination between advanced and non-advanced tumors, and MR has moderate to excellent specificity at identifying portal venous and hepatic venous/IVC involvement.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 3.

Update on the Pathology of Pediatric Liver Tumors: A Pictorial Review

Liver tumors in children are uncommon and show remarkable morphologic heterogeneity. Pediatric tumors may arise from either the epithelial or mesenchymal component of the liver and rarely may also show both lines of differentiation. Both benign and malignant liver tumors have been reported in children. The most common pediatric liver tumors by age are benign hepatic infantile hemangiomas in neonates and infants, malignant hepatoblastoma in infants and toddlers, and malignant hepatocellular carcinoma in teenagers. Here, we provide an up-to-date review of pediatric liver tumors. We discuss the clinical presentation, imaging findings, pathology, and relevant molecular features that can help in the correct identification of these tumors, which is important in managing these children.

Intratumoral erythroblastic islands restrain anti-tumor immunity in hepatoblastoma

Erythroblastic islands (EBIs) are the specialized structures for erythropoiesis, but they have never been found functional in tumors. As the most common pediatric liver malignancy, hepatoblastoma (HB) requires more effective and safer therapies to prevent progression and the lifelong impact of complications on young children. However, developing such therapies is impeded by a lack of comprehensive understanding of the tumor microenvironment. By single-cell RNA sequencing of 13 treatment-naive HB patients, we discover an immune landscape characterized by aberrant accumulation of EBIs, formed by VCAM1⁺ macrophages and erythroid cells, which is inversely correlated with survival of HB. Erythroid cells inhibit the function of dendritic cells (DCs) via the LGALS9/TIM3 axis, leading to impaired anti-tumor T cell immune responses. Encouragingly, TIM3 blockades relieve the inhibitory effect of erythroid cells on DCs. Our study provides an immune evasion mechanism mediated by intratumoral EBIs and proposes TIM3 as a promising therapeutic target for HB.

Nucleic acid therapy in pediatric cancer

The overall survival, progress free survival, and life quality of cancer patients have improved due to the advance in minimally invasive surgery, precision radiotherapy, and various combined chemotherapy in the last decade. Furthermore, the discovery of new types of therapeutics, such as immune checkpoint inhibitors and immune cell therapies have facilitated both patients and doctors to fight with cancers. Moreover, in the context of the development in biocompatible and cell type targeting nano-carriers as well as nucleic acid-based drugs for initiating and enhancing the anti-tumor response have come to the age. The treatment paradigms utilization of nucleic acids, including short interfering RNA (siRNA), antisense oligonucleotides (ASO), and messenger RNA (mRNA), can target specific protein expression to achieve the therapeutic effects. Over ten nucleic acid therapeutics have been approved by the FDA and EMA in rare diseases and genetic diseases as well as dozens of registered clinical trails for varies cancers. Though generally less dangerous of pediatric cancers than adult cancers was observed during the past decades, yet pediatric cancers accounted for a significant proportion of child deaths which hurt those family very deeply. Therefore, it is necessary to pay more attention for improving the treatment of pediatric cancer and discovering new nucleic acid therapeutics which may help to improve the therapeutic effect and prognoses in turns to ameliorate the survival period and quality of life for children patient. In this review, we focus on the nucleic acid therapy in pediatric cancers.

'Teratoid' Hepatoblastoma: An Intriguing Variant of Mixed Epithelial-Mesenchymal Hepatoblastoma

Liver neoplasms are quite rare in childhood. They often involve 6.7 cases per 10 million children aged 18 years or younger. Hepatoblastoma (HB) is the most frequent tumor, but this neoplasm's rarity points essentially to the difficulty of performing biologic studies and large-scale therapeutic trials. On the pathological ground, HB is separated into an entirely epithelial neoplasm or a mixed neoplasm with epithelial and mesenchymal components. This last category has been further subdivided into harboring teratoid features or not. The 'teratoid' HB includes a mixture of components with heterologous origin. The heterologous components include neuroectoderm, endoderm, or melanin-holding cells with or without mesenchymal components. The most important criterium for the teratoid component is neuroepithelium, melanin, and, more recently, a yolk-sac-like component and neuroendocrine components. The mesenchymal components include muscle, osteoid, and cartilage, which are most often observed mainly in 'teratoid' neoplasms. The teratoid component or mesenchymal components are diagnosed with biopsies. They appear more prominent after chemotherapy due to the response and shrinkage of epithelial elements and non- or low-responsive components of mixed HB. This review focuses on the clinical, radiological, and pathological findings of HB with teratoid features.

The role of m6A modification in pediatric cancer

With the development of RNA modification research, the importance of N6-methyladenosine (m6A) in tumors cannot be ignored. m6A promotes the self-renewal of tumor stem cells and the proliferation of tumor cells. It affects post-transcriptional gene expression through epigenetic mechanisms, combining various factors to determine proteins' fate and altering the biological function. This modification process runs through the entire tumors, and genes affected by m6A modification may be the critical targets for cancers breakthroughs. Though generally less dangerous than adult cancer, pediatric cancer accounts for a significant proportion of child deaths. What is more alarming is that the occurrences of adult tumors are highly associated with the poor prognoses of pediatric tumors. Therefore, it is necessary to pay attention to the importance of pediatric cancer and discover new therapeutic targets, which will help improve the therapeutic effect and prognoses of the diseases. We collected and investigated m6A modification in pediatric cancers based on mRNA and non-coding RNA, finding that m6A factors were involved in glioma, hepatoblastoma, nephroblastoma, neuroblastoma, osteosarcoma, medulloblastoma, retinoblastoma, and acute lymphoblastic leukemia. Consequently, we summarized the relationships between the m6A factors and these pediatric cancers.

Pediatric Liver Tumors: Updates in Classification

Malignant primary liver tumors are rare in children. Yet a wide histologic spectrum is seen, particularly in hepatoblastoma, the most common malignant liver tumor in children. Furthermore, there can be significant morphologic overlap with hepatocellular carcinoma, the second most common pediatric liver malignancy, and tumors with hybrid features of hepatoblastoma and hepatocellular carcinoma are also reported (currently placed in the provisional category of malignant hepatocellular neoplasm, not otherwise specified). This review provides detailed morphologic descriptions and updates in the evolving clinical context of these tumors, and presents recent molecular advances that may further help in accurate classification of these tumors, which is critical in their management.

Prognostic analysis for children with hepatoblastoma with lung metastasis: A single-center analysis of 98 cases

AIMS

To analyze the factors affecting the prognosis of hepatoblastoma (HB) with lung metastasis in children.

METHODS

The HB patients with lung metastases admitted to Beijing Tongren Hospital, Capital Medical University were collected. The clinical data, overall results, and prognostic factors were analyzed. Multivariate analysis was done by the Cox proportional hazards model for patients' prognosis.

RESULTS

Finally, 98 HB patients (64 boys and 34 girls) with lung metastasis met the inclusion criteria, in which 64 patients had lung metastases at diagnosis (median age, 22.3 months) and 34 patients developed lung metastases while on treatment (median time, 6.5 months). The survival time and 5-year survival rate of patients with standard treatment were significantly longer than that of without standard treatment (P < .001). The survival time and 3-year survival rate had no difference between patients underwent lung metastasectomy and without lung metastasectomy (P = .099), between different diagnosis time of lung metastasis in HB patients (P = .37), between each histology type (P = .313), and different PRETEXT stage (P = .353). While the survival time and 3-year survival rate of patients with lung metastasis alone were significantly longer than that of patients with extrapulmonary involvement (P = .007). Multivariate Cox proportional hazards model revealed that the lung metastasis accompanied with extrapulmonary involvement was a risk factor affecting prognosis (HR = 0.460, 95% CI 0.239-0.888).

CONCLUSIONS

For HB children with lung metastatic, extrapulmonary involvement might be a high-risk factor of prognosis and standardized treatment with lung metastasectomy might prolong the survival time of them.

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.

Hepatoblastoma and Pediatric Hepatocellular Carcinoma: An Update

Hepatoblastomas (HBs) and pediatric hepatocellular carcinomas (HCCs) together account for almost 80% of primary malignant liver tumors in children and adolescents/young adults. Children's Hepatic International Collaboration (CHIC), Children's Oncology Group (COG), SociétéInternationale d'Oncologie Pédiatrique (SIOP), and International Childhood Liver Tumors Strategy Group trials have contributed to define prognostic factors and risk stratification in these tumors. The recently proposed histologic International Consensus classification of HB and HCC in children based on retrospective analysis from CHIC cases represents the base to define entities with homogeneous clinicopathologic and molecular features. This review will provide a morphologic guide for the upcoming International Liver Tumor treatment trial (Pediatric Hepatic International Tumour Trial) to be conducted through several continents. There will be an emphasis on molecular features and immunohistochemical markers for the definition of the individual histologic subtypes of HB and to better characterize the group of liver tumors in the provisional category of hepatocellular neoplasm-not otherwise specified. A brief overview of HCC in children will also be provided.

Impact of microscopically margin-positive resection on survival in children with hepatoblastoma after hepatectomy: a retrospective cohort study

BACKGROUND

Impact of R1 (microscopically margin-positive) resection on survival of patients with hepatoblastoma (HB) remains debatable. This study aimed to compare the long-term outcomes of R0 (microscopically margin-negative) and R1 resection for HB in children after hepatectomy.

METHODS

We retrospectively reviewed files of children with HB who underwent resection at our institution between September 1, 2005, and November 30, 2017. Survival analyses and prognostic factors were evaluated using Kaplan-Meier curves and Cox regression models.

RESULTS

Of 259 patients, 218 (84.2%) underwent R0 and 41 (15.8%) R1 resection. After adjusting for confounding factors, R1 resection demonstrated non-significantly lower overall survival (OS: hazard ratio [HR] = 0.75; 95% CI 0.34-1.64) and shorter event-free survival (EFS: HR = 0.97; 95% CI 0.53-1.78) rates than R0 resection. However, stratified analysis showed significantly increased risk of poor OS and EFS in patients with metastasis and mixed epithelial/mesenchymal pathologic subtype in R1 compared with R0 resection (P values for interactions < 0.05). There was no significant difference between R0 resection with metastasis and R1 resection with metastasis in the incidence of local recurrence (P = 0.494); however, a significant difference in the incidence of local recurrence was seen between R0 and R1 resection for subgroups with mixed pathologic subtypes (P = 0.035).

CONCLUSIONS

With effective chemotherapy, microscopic margin status may not be associated with survival outcome in children with HB undergoing hepatectomy. However, stratified analysis showed that R1 resection might be associated with decreased survival in children with mixed epithelial/mesenchymal HB, compared with R0 resection, and not affect survival outcomes in those with an epithelial subtype and without metastasis.

Surgical treatment strategy for advanced hepatoblastoma: Resection versus transplantation

BACKGROUND

Excellent outcomes of the extreme procedure of liver resection (LR) for advanced hepatoblastoma (HB) have been achieved in recent reports. However, liver transplantation (LT) remains the only surgical treatment for patients with unresectable HB. The aim of this study was to evaluate our retrospective data for cases of advanced HB necessitating surgical intervention and analyze the prognostic factors of recurrence by comparing patients with tumors resected by LR and LT.

PATIENTS AND METHODS

We retrospectively reviewed 24 children with PRETEXT II/III/IV tumors that required consideration for LT between August 2011 and September 2016.

RESULT

The staging at the time of the diagnosis was PRETEXT II/III/IV in 1/13/10 patients, respectively, while the preoperative staging after neoadjuvant chemotherapy was POSTTEXT II/III/IV in 5/17/2 patients. Among those 24 patients, complete resection of the primary tumor was achieved with LT in 12 patients and LR in 12 patients. A high serum level of alpha-fetoprotein (AFP) at the time of surgery, no significant decrease in the rate of change of AFP, and low tumor shrinkage rate were related to the risk of tumor recurrence, and patients with tumors resected by LR with those risks had a higher recurrence rate than those without them. The overall survival was higher in patients with tumors resected by LT (100%) than in patients with tumors resected by LR.

CONCLUSION

Patients with advanced HB with a poor response to chemotherapy should definitively be prioritized for primary LT, given the possibility of vascular invasion and microscopic residual tumor.

Hepatoblastoma in a child with dextrocardia and possible histopathological alteration reminiscent of hepatocellular carcinoma after neoadjuvant chemotherapy

It is quite unambiguous and interesting that postchemotherapy histology of hepatoblastoma may mimicry that of hepatocellular carcinoma which should be differentiated by proper immunohistochemistry and cytology, if possible, for further management and predict prognosis.

Histological and immunohistochemical study of hepatoblastoma: correlation with tumour behaviour and survival

Background

Hepatoblastoma (HB) has different histological subtypes, with varying prognosis. Though the survival has drastically improved, subsets of patients are not responsive to therapy. Therefore, it becomes important to determine the factors which affect the behaviour of the tumour. This study was aimed to look at the histopathological subtypes and compare with immunohistochemical (IHC) expression of CK19, beta-catenin and EpCAM and survival.

Methods

This study included 55 cases of HB. IHC expression of CK19, beta-catenin and EpCAM were correlated with histological subtypes, tumour behaviour, response to chemotherapy and survival.

Results

Most common epithelial subtype was fetal (43.2%) and mixed epithelial (54.8%) in pre- and post-chemotherapy groups respectively. Microvascular invasion (MVI) was present in 14/33 resected tumours. CK19 expression was seen in 54.2% and 72.2% of embryonal subtype, nuclear beta-catenin expression in 48.7% and 57.1% and EpCAM in 100% and 82.1% of tumours in pre- and post-chemotherapy groups, respectively. Fetal subtype had a lesser chance of MVI, recurrence, metastasis and death. Beta-catenin expression was associated with lower event free survival (EFS) and EpCAM with ≥50% viable tumour following chemotherapy (P=0.04). Age at diagnosis ≤2 years, male sex, alpha-fetoprotein <10,000 IU/mL following chemotherapy, solitary tumour (P=0.001), size ≤5 cm, pretreatment extent of disease (PRETEXT) I&II, mitosis ≤2/10 high power fields (hpf), viable tumour <50% (P=0.04) and absent nuclear expression of beta-catenin, predicted a higher EFS rate.

Conclusions

Beta-catenin expression is associated with lower EFS and EpCAM expression with tumour viability. Multifocality and viable tumour ≥50% were significant factors predicting lower EFS. These factors should be included in the prognostication of HBs.

Hepatocellular malignant neoplasm, NOS: a clinicopathological study of 11 cases from a single institution

AIMS

The primary aim of this study is to characterize hepatocellular malignant neoplasm, NOS (HEMNOS), a new provisional entity describing a subset of paediatric hepatocellular tumours, which have histological features of neither typical hepatoblastoma (HB) nor hepatocellular carcinoma (HCC).

METHODS AND RESULTS

The clinicopathological features of 11 patients with HEMNOS were analysed retrospectively. The median age and serum alpha-fetoprotein level at diagnosis was 7 years and 182 000 ng/ml, respectively. Ten patients presented with pretreatment extent of disease (PRETEXT) stages III/IV multifocal tumours, eight with major vascular involvement, three with lung metastases and three with extrahepatic extension. The original pathology diagnoses were: HB in seven patients, HCC in two and HEMNOS in two. Our pathology review of pre-chemotherapy specimens showed that six tumours had equivocal/overlapping histological features of HB and HCC, four had predominant HB histology along with focal HCC-like histology and one had HB histology. Seven of nine post-chemotherapy resection specimens showed predominant HCC-like histology. Beta-catenin, glypican 3 and spalt-like transcription factor 4 immunostaining showed that all the tumours had a mixed HB/HCC immunophenotype. Telomerase reverse transcriptase immunostaining showed nuclear staining in nine of the 11 tumours. All patients received chemotherapy and achieved gross total primary tumour resection. Nine of the 11 patients were treated with established HB chemotherapy regimens. After a median follow-up of 6.1 years (range: 1.2-11.8 years), all patients were in remission.

CONCLUSIONS

HEMNOS is a subtype of HB with focal HCC-like histology, a high-risk clinical profile but favourable outcome following chemotherapy and complete tumour resection.

Tumor histopathological response to neoadjuvant chemotherapy in childhood solid malignancies: is it still impressive?

The management of oncological malignancies has significantly improved over the last decades. In modern medicine, new concepts and trends have emerged paving the way for the era of personalized and evidence-based strategies adapted to the patients’ prognostic variables and requirements. Several challenges do exist that are encountered during the management, including the difficulty to assess chemotherapy response with certainty. Having known that neoadjuvant chemotherapy might be the only solution for a proportion of patients with tumors that are unresectable at diagnosis, emergence of strategies that use risk group-directed therapy became an integral part in the management of oncological malignancies. Tumor histopathological change post neoadjuvant chemotherapy is one of the most important predictors of management outcome and is being used in many chemotherapy protocols as an essential determinant of the most suitable postoperative chemotherapy regimen. Bone tumors are the classic models of this approach; however, other childhood solid tumors show significant variations in outcome as a result of tumor histopathological response to neoadjuvant chemotherapy. The aim of this review is therefore to summarize the significance of histopathological responses seen after neoadjuvant chemotherapy in childhood solid tumors. Moreover, it suggests that the effect on tumor histopathology through modifying neoadjuvant chemotherapy and, on the other hand, toxicities from intensifying adjuvant chemotherapy might either necessitate the change of a number of arm groups in different protocol regimens or include newer chemotherapeutic agents adjuvantly for better outcome and lesser toxicities in poor tumor histopathological responders.

Hepatoblastoma

Hepatoblastoma is the most common primary malignant hepatic tumor of infancy and childhood, occurring predominantly in the first two years of life. The management of hepatoblastoma has changed markedly over the last 3 decades; neoadjuvant chemotherapy is now standard, particularly in unresectable tumors resulting in considerable preoperative tumor shrinkage and sometimes near total ablation of the tumor. A 20 month old infant was incidentally found to have a 7.6cm right sided retroperitoneal tumor on routine screening ultrasonography for left ureteral stenosis. Serum alpha fetoprotein was elevated. Biopsy revealed hepatoblastoma, mixed epithelial and embryonal type without mesenchymal elements. He underwent neoadjuvant chemotherapy. Although the tumor had decreased considerably in size, close proximity to major vascular structures precluded safe resection. Liver transplantation was performed; the explanted liver showed complete tumor necrosis with no residual malignancy. The postoperative course was uncomplicated and he is continuing on sixth cycle of chemotherapy.

Towards an international pediatric liver tumor consensus classification: proceedings of the Los Angeles COG liver tumors symposium

Liver tumors are rare in children, and their diagnoses may be challenging particularly because of the lack of a current consensus classification system. Systematic central histopathological review of these tumors performed as part of the pediatric collaborative therapeutic protocols has allowed the identification of histologic subtypes with distinct clinical associations. As a result, histopathology has been incorporated within the Children's Oncology Group (COG) protocols, and only in the United States, as a risk-stratification parameter and for patient management. Therefore, the COG Liver Tumor Committee sponsored an International Pathology Symposium in March 2011 to discuss the histopathology and classification of pediatric liver tumors, and hepatoblastoma in particular, and work towards an International Pediatric Liver Tumors Consensus Classification that would be required for international collaborative projects. Twenty-two pathologists and experts in pediatric liver tumors, including those serving as central reviewers for the COG, European Société Internationale d'Oncologie Pédiatrique, Gesellschaft für Pädiatrische Onkologie und Hämatologie, and Japanese Study Group for Pediatric Liver Tumors protocols, as well as pediatric oncologists and surgeons specialized in this field, reviewed more than 50 pediatric liver tumor cases and discussed classic and newly reported entities, as well as criteria for their classification. This symposium represented the first collaborative step to develop a classification that may lead to a common treatment-stratification system incorporating tumor histopathology. A standardized, clinically meaningful classification will also be necessary to allow the integration of new biological parameters and to move towards clinical algorithms based on patient characteristics and tumor genetics, which should improve future patient management and outcome.

Relationship of β-catenin and postchemotherapy histopathologic changes with overall survival in patients with hepatoblastoma

AIMS

Histopathologic spectrum and expression of β-catenin were analyzed in patients with hepatoblastoma, diagnosed over a period of 14 years. These were correlated with the survival outcome. The morphologic features subsequent to chemotherapy were also analyzed.

METHODS AND RESULTS

Histomorphologic features were studied on paraffin-embedded sections. There were 24 cases with 15 fetal, 4 embryonal, 4 macrotrabecular, and 1 of small cell subtype. Follow-up was available in 20 cases (mean = 16.8 mo). β-catenin immunostaining performed by indirect immunoperoxidase method revealed 14 cases with nuclear and 10 cases with cytoplasmic positivity. Statistical analysis revealed no significant correlation between morphologic subtype and survival. Significant difference in survival was noted with respect to tumor stage, mitotic index, and β-catenin staining pattern. Cases with nuclear expression had a mean survival of 71.54 ± 8.1 months in comparison with 14.71 ± 6.5 months in cases with cytoplasmic expression. Besides osteoid and cartilage formation, interesting postchemotherapy findings were the presence of tumoral maturation, hepatocellular carcinoma-like areas, peliotic-like foci, and "glomeruloid clusters."

CONCLUSIONS

Nuclear β-catenin expression is not a poor prognostic factor and this might be indicative of different genetic alterations in hepatoblastoma in the Indian subcontinent. There was no significant correlation between histologic subtype and osteoid differentiation with survival. The histopathologic changes observed were peliotic-like areas, tumoral maturation, hepatocellular carcinoma-like changes, and glomeruloid clusters besides the well-established features of osteoid differentiation after chemotherapy.

Tumor necrosis predicts survival following neo-adjuvant chemotherapy for hepatoblastoma

BACKGROUND

Tumor response to chemotherapy has been shown to predict outcome in children with acute lymphoblastic leukemia, osteosarcoma, and Ewing Sarcoma. We evaluated whether tumor necrosis following neo-adjuvant chemotherapy is prognostic for survival in hepatoblastoma (HB).

PROCEDURE

Primary tumors from children with newly diagnosed stage III and IV HB who underwent surgical resection following neo-adjuvant chemotherapy were evaluated histologically for the extent of tumor necrosis (total diameter of necrotic and fibrotic tissue divided by total diameter of tumor). Clinical features, laboratory values, pathological features, treatment delivered, and vital status were recorded. Univariate and multivariate Cox regression analyses were performed to evaluate prognostic factors.

RESULTS

Thirty-two patients were evaluable. After a median of four cycles of neo-adjuvant chemotherapy gross total surgical resection was achieved in 29 patients and complete resection documented by histology in 22 patients. Three-year event free survival (EFS) and overall survival (OS) of the evaluable patients were 70.3 ± 8.3% and 76.8 ± 7.6%, respectively. Extent of tumor necrosis, platelet count at diagnosis, decline in serum alpha fetoprotein, and surgical margin status (positive vs. negative) were statistically significant predictors for both EFS and OS by univariate analysis. Multivariate analyses revealed that extent of tumor necrosis and surgical margin status predicted improved EFS (P < 0.001) and OS (P < 0.0001).

CONCLUSIONS

Extent of tumor necrosis following neo-adjuvant chemotherapy is an independent prognostic factor in patients with newly diagnosed HB. Histological response may potentially be used in strategies to modify post-surgical therapy to improve survival in HB.

Teratoid Hepatoblastoma With Abundant Neuroendocrine and Squamous Differentiation With Extensive Parenchymal Metastasis

Teratoid hepatoblastoma is a rare histologic subtype accounting for 4% to 10% of all hepatoblastomas and is characterized by the presence of divergent differentiation, including squamous, mucinous, melanocytic, cartilaginous, osseous, skeletal muscle, and neural elements. It is postulated that the teratoid elements might derive from multipotential less-differentiated stem cells. Teratoid hepatoblastoma responds poorly to chemotherapy and therefore recognition of this variant has prognostic implications. We describe a 1½-year-old child with teratoid hepatoblastoma characterized by unusual clinical and morphologic patterns including prominent neuroendocrine and squamous differentiation.

Adult hepatoblastoma: learning from children

Hepatoblastoma is the most common malignant liver tumour in infants and young children. Its occurrence in the adult population is debated and has been questioned. The aim of this paper is to review the histological and clinical features of adult hepatoblastoma as described in the adult literature, and to compare the findings with those of paediatric hepatoblastoma. The developmental and molecular aspects of hepatoblastoma are reviewed and their potential contribution to diagnosis of adult hepatoblastoma discussed. Case reports of adult hepatoblastoma identified by a PubMed search of the English, French, German, Italian, and Spanish literature through March 2011 were reviewed. Forty-five cases of hepatoblastoma were collected. Age at presentation was variable. Survival was uniformly poor, except for the rare patients who presented with the relatively differentiated, foetal type. The common denominator between adult and paediatric cases is the occurrence of embryonal or immature aspect of the tumours. Whether the adult cases of hepatoblastoma represent blastemal tumours, stem cell tumours, or unusual differentiation patterns in otherwise more frequent adult liver tumours remains to be established. Adult tumours labelled as hepatoblastoma are characterised by malignant appearing mesenchymal components. Surgical management is the cornerstone of therapy in children and also appears to confer an improved prognosis in adults. Whether adult hepatoblastoma exists, remains controversial. Indeed, several features described in adult cases are markedly different from hepatoblastoma as it is understood in children, and other differential diagnoses should also be entertained. Nonetheless, hepatoblastoma should be considered in adults presenting with primary liver tumours in the absence of pre-existing liver disease. Adult and paediatric patients with immature hepatoblastoma appear to have worse outcomes, and adults presenting with presumed hepatoblastoma have an overall poorer prognosis than children with hepatoblastoma. In all patients, surgery should be the treatment of choice, neoadjuvant chemotherapy is advisable.

Characterisation of the cell line HC-AFW1 derived from a pediatric hepatocellular carcinoma

Current treatment of paediatric hepatocellular carcinoma (HCC) is often inefficient due to advanced disease at diagnosis and resistance to common drugs. The aim of this study was to generate a cell line derived from a paediatric HCC in order to expand research in this field. We established the HC-AFW1 cell line from a liver neoplasm of a 4-year-old boy through culturing of primary tumor specimens. The cell line has been stable for over one year of culturing and has a doubling time of 40 h. The tumour cells have an epithelial histology and express HCC-associated proteins such as Alpha-fetoprotein (AFP), Glypican 3, E-cadherin, CD10, CD326, HepPar1 and Vimentin. Forty-nine amino acids in exon 3 of β-Catenin that involve the phosphorylation sites of GSK3 were absent and β-Catenin is detectable in the cell nuclei. Cytogenetic analysis revealed large anomalies in the chromosomal map. Several alterations of gene copy numbers were detected by genome-wide SNP array. Among the different drugs tested, cisplatin and irinotecan showed effective inhibition of tumour cell growth in a proliferation assay at concentrations below 5 µg/ml. Subcutaneous xenotransplantation of HC-AFW1 cells into NOD/SCID mice resulted in fast growing dedifferentiated tumours with high levels of serum AFP. Histological analyses of the primary tumour and xenografts included national and international expert pathological review. Consensus reading characterised the primary tumour and the HC-AFW1-derived tumours as HCC. HC-AFW1 is the first cell line derived from a paediatric HCC without a background of viral hepatitis or cirrhosis and represents a valuable tool for investigating the biology of and therapeutic strategies for childhood HCC.

Hepatoblastoma: recent developments in research and treatment

Hepatoblastoma is the most common liver tumor of early childhood. According to recent studies its incidence seems to be increasing in North America and Europe. Since new histological variants have been described recently the formerly clear-cut distinction of hepatoblastoma and hepatocellular carcinoma may not be valid anymore and a new histological classification will be inaugurated by an international working group. Recent research identified prognostically relevant gene signatures as well as potential molecular targets for therapy of hepatoblastoma. The multicentric study groups in the USA, Europe and Japan recommend cisplatin based chemotherapy for neoadjuvant and adjuvant treatment. However, their risk stratification systems and general treatment strategies differ substantially. Therefore the four groups agreed to pool their patients' data for an analysis of prognostic criteria which can be used for defining common risk groups. While 90% of standard risk and 65% of high risk hepatoblastomas can be cured, the still dismal outcome of multifocal disseminated and metastasising tumors warrants the investigation of new cytotoxic drugs and substances against specific molecular targets.

Treatment outcomes for hepatoblastoma: experience of 35 cases at a single institution

BACKGROUND/PURPOSE

Hepatoblastoma is the most common malignant liver tumor in children. Comparative studies have elucidated the optimal pre- or postoperative chemotherapeutic regimens. The aim of this study was to investigate the prognostic significance of baseline tumor characteristics for overall survival and disease-free survival in children with hepatoblastoma.

METHODS

There were 19 male and 16 female children with a median age of 19 months at diagnosis (range: 1-169 months) in our institution between February 1990 and June 2009. We reviewed the clinical presentation, serum α-fetoprotein level at diagnosis, histological subtype, treatment, and outcomes.

RESULTS

Twenty-seven patients (78%) underwent neoadjuvant chemotherapy. The majority of patients subsequently underwent either hemihepatectomy (56%) or bisegmentectomy (16%). Only six patients underwent extended hepatic resection, and one of them required rescue liver transplantation. During follow-up, six patients died of progressive disease and two of perioperative mortality. Four of the six who died had pulmonary metastases at the time of diagnosis or follow-up. The median survival time was 28 months (range: 1-181 months). Five-year overall survival was 67.7% (95% confidence interval: 52.0-87.8%) and disease-free survival was 60.2% (95% confidence interval: 41.9-86.5%).

CONCLUSION

The potential down-staging effect of neoadjuvant chemotherapy on hepatoblastoma might facilitate remission and convert unresectable tumors into operable ones.

Activated NOTCH2 is overexpressed in hepatoblastomas: an immunohistochemical study

Hepatoblastoma is a pediatric malignancy characterized by the uncontrolled proliferation of immature hepatocytes (hepatoblasts). This disease is diagnosed primarily in children younger than 5 years and is disproportionately observed in former premature infants. Cytogenetically, hepatoblastoma is characterized by numerical aberrations, as well as unbalanced translocations involving the proximal region of chromosome 1q. The NOTCH2 gene has been mapped to this locus, and it is well established that the NOTCH gene family is an important regulator of several developmental pathways. Specifically, the NOTCH2 protein is known to delay hepatoblast maturation during early hepatic organogenesis, and the reduction of NOTCH2 expression correlates with the differentiation of hepatoblasts into hepatocytes and biliary cells in the developing liver. We hypothesized that NOTCH2 is involved in the pathogenesis of hepatoblastoma by maintaining a population of undifferentiated hepatoblasts. We studied the immunohistochemical expression of NOTCH2 and its isoforms NOTCH1, NOTCH3, and NOTCH4 and the NOTCH2 primary ligand JAGGED1 in hepatoblastomas. Compared with the normal liver, an increased level of NOTCH2 expression was seen in 22 of 24 (92%) hepatoblastomas. There was no significant staining for other NOTCH isoforms and JAGGED1 in hepatoblastomas. Therefore, we suggest that NOTCH2 expression and activation, independent of JAGGED1 expression, may contribute to the pathogenesis of hepatoblastoma. In the hepatoblastoma sinusoidal vasculature, we saw NOTCH3 and NOTCH1 expression. These observations have potential implications with regard to therapeutic targeting of the NOTCH signaling pathway in hepatoblastomas.

Liver neoplasia in children

Management of pediatric liver tumors has significantly improved over the last 2 decades. The management options for hepatocelluar carcinoma (HCC) are not well defined. In the pediatric context, the main clinical aims are to reduce chemotherapy toxicity (predominantly ototoxicity and nephrotoxicity) in children treated for hepatoblastoma and to investigate additional modes of treatment for HCC. An increasing number of children develop HCC in the background of chronic liver disease, and screening methods need to be better observed.

Prognostic value of hedgehog signal component expressions in hepatoblastoma patients

OBJECTIVE

Activation of hedgehog (Hh) pathway has been implicated in the development of human malignancies. Hh as well as related downstream target genes has been extensively studied in many kinds of malignant tumours for clinical diagnostic or prognostic utilities. This study aimed at investigating whether Hh molecules provides a molecular marker of hepatoblastoma malignancy.

METHODS

We obtained tissue sections from 32 patients with hepatoblastoma as well as cholestasis and normal control. Immunohistochemical analysis were performed to determine Hh signal components in human hepatoblastoma. The prognostic significance of single expression of Hh signal components were evaluated using Cox proportional hazards regression models and Kaplan-Meier survival analysis for statistical analysis.

RESULTS

Expression of Hh signal components showed an increase in hepatoblastoma compared with cholestasis and normal tissues. There was a positive correlation between Smo or Gli1 expression and tumor clinicopathological features, such as histological type, tumor grade, tumor size and clinical stage. Both Smo or Gli1 protein high expression was significantly associated with poor prognosis by univariate analyses and multivariate analyses.

CONCLUSIONS

Abnormal Hh signaling activation plays important roles in the malignant potential of hepatoblastoma. Gli1 expression is an independent prognostic marker.