Genome-Wide DNA Methylation Profiling as Frontline Diagnostics for Central Nervous System Embryonal Tumors in Hong Kong.

This paper examines the link between CNS tumor biology and heterogeneity and the use of genome-wide DNA methylation profiling as a clinical diagnostic platform. CNS tumors are the most common solid tumors in children, and their prognosis remains poor. This study retrospectively analyzed pediatric patients with CNS embryonal tumors in Hong Kong between 1999 and 2017, using data from the territory-wide registry and available formalin-fixed paraffin-embedded tumor tissue. After processing archival tumor tissue via DNA extraction, quantification, and methylation profiling, the data were analyzed by using the web-based DKFZ classifier (Molecular Neuropathology (MNP) 2.0 v11b4) and t-SNE analysis. Methylation profiles were deemed informative in 85 samples. Epigenetic data allowed molecular subgrouping and confirmed diagnosis in 65 samples, verified histologic diagnosis in 8, and suggested an alternative diagnosis in 12. This study demonstrates the potential of DNA methylation profiling in characterizing pediatric CNS embryonal tumors in a large cohort from Hong Kong, which should enable regional and international collaboration in future pediatric neuro-oncology research.

Incidence and Predictors for Oncologic Etiologies in Chinese Children with Pituitary Stalk Thickening.

BACKGROUND: With the increasing use of magnetic resonance imaging (MRI) in the evaluation of children with endocrine disorders, pituitary stalk thickening (PST) poses a clinical conundrum due to the potential for underlying neoplasms and challenges in obtaining a tissue biopsy. The existing literature suggests Langerhans cell histiocytosis (LCH) to be the commonest (16%) oncologic cause for PST, followed by germ cell tumors (GCTs, 13%) (CCLG 2021). As the cancer epidemiology varies according to ethnicity, we present herein the incidence and predictors for oncologic etiologies in Hong Kong Chinese children with PST. METHODS: Based on a territory-wide electronic database, we reviewed patients aged < 19 years who presented to three referral centers with endocrinopathies between 2010 and 2022. Records for patients who underwent at least one MRI brain/pituitary were examined (n = 1670): those with PST (stalk thickness ≥ 3 mm) were included, while patients with pre-existing cancer, other CNS and extra-CNS disease foci that were diagnostic of the underlying condition were excluded. RESULTS: Twenty-eight patients (M:F = 10:18) were identified. The median age at diagnosis of PST was 10.9 years (range: 3.8-16.5), with central diabetes insipidus (CDI) and growth hormone deficiency (GHD) being the most frequent presenting endocrine disorders. At a median follow-up of 4.8 years, oncologic diagnoses were made in 14 patients (50%), including 13 GCTs (46%; germinoma = 11, non-germinoma = 2) and one LCH (4%). Among patients with GCTs, 10 were diagnosed based on histology, two by abnormal tumor markers and one by a combination of histology and tumor markers. Three patients with germinoma were initially misdiagnosed as hypophysitis/LCH. The cumulative incidence of oncologic diagnoses was significantly higher in boys and patients with PST at presentation ≥6.5 mm, CDI or ≥2 pituitary hormone deficiencies at presentation and evolving hypopituitarism (all p < 0.05 by log-rank). CONCLUSIONS: A higher rate of GCTs was observed in Chinese children with endocrinopathy and isolated PST. The predictors identified in this study may guide healthcare providers in Asia in clinical decision making. Serial measurement of tumor markers is essential in management.

DICER1 -Altered Extraovarian Moderately Differentiated Sertoli-Leydig Cell Tumor: Report of a Rare Case.

We report an unusual case of a pelvic extraovarian moderately differentiated Sertoli-Leydig cell tumor arising in a 4-yr-old female. The tumor contained a DICER1 pathogenic variant which was absent in the germline ruling out DICER1 syndrome. In reporting this case, we discuss the differential diagnosis and possible histogenesis and review reported cases of extraovarian Sertoli-Leydig cell tumor.

Incidence and Outcomes of CNS Tumors in Chinese Children: Comparative Analysis With the Surveillance, Epidemiology, and End Results Program.

PURPOSE: Despite being the most common pediatric solid tumors, incidence and outcome of CNS tumors in Chinese children have not been systematically reported. We addressed this knowledge gap by comparing the epidemiology of pediatric CNS tumors in Hong Kong and the United States. PATIENTS AND METHODS: Data between 1999 and 2016 from a population-based cancer registry in Hong Kong, China, on patients < 18 years old with CNS tumors (Hong Kong cohort) and from the US SEER Program (Asian/Pacific Islander and all ethnicities) were compared. Incidence and overall survival (OS) by histology were evaluated. RESULTS: During the study period, 526 children were newly diagnosed with CNS tumors in Hong Kong (crude incidence rate, 2.47 per 100,000; 95% CI, 2.26 to 2.69). Adjusted incidences were significantly lower in the Hong Kong (2.51; 95% CI, 2.30 to 2.74) than in the SEER (Asian/Pacific Islander: 3.26; 95% CI, 2.97 to 3.57; P < .001; all ethnicities: 4.10 per 100,000; 95% CI, 3.99 to 4.22; P < .001) cohorts. Incidences of germ cell tumors (0.57 v 0.24; P < .001) were significantly higher, but those of glial and neuronal tumors (0.94 v 2.61; P < .001), ependymomas (0.18 v 0.31; P = .005), and choroid plexus tumors (0.08 v 0.16; P = .045) were significantly lower in Hong Kong compared with SEER (all ethnicities) cohorts. Compared with the SEER (Asian/Pacific Islander) cohort, histology-specific incidences were similar except for a lower incidence of glial and neuronal tumors in Hong Kong (0.94 v 1.74; P < .001). Among cohorts, OS differed only for patients with glial and neuronal tumors (5-year OS: Hong Kong, 52.5%; SEER [Asian/Pacific Islander], 73.6%; SEER [all ethnicities], 79.9%; P < .001). CONCLUSION: We identified important ethnic differences in the epidemiology of CNS tumors in Chinese children. These results will inform the development of pediatric neuro-oncology services in China and aid further etiologic studies.

Perforin gene mutation in familial haemophagocytic lymphohistiocytosis: the first reported case from Hong Kong.

Familial haemophagocytic lymphohistiocytosis is a rare but invariably fatal disease without haematopoietic stem cell transplantation. Genetic defect identification is useful for confirming a clinical diagnosis, predicting the risk of future recurrence, and defining haemophagocytic lymphohistiocytosis predisposition in asymptomatic family members. Notably, familial haemophagocytic lymphohistiocytosis type 2 associates with mutations in the perforin gene (PRF1) which is the most frequent subtype of familial haemophagocytic lymphohistiocytosis. Although perforin gene mutations have been described in Asians, they are largely reported from Japan. The case reported here is the first familial haemophagocytic lymphohistiocytosis type 2 patient in Hong Kong with an identified perforin gene mutation.

Minimal residual disease-based risk stratification in Chinese childhood acute lymphoblastic leukemia by flow cytometry and plasma DNA quantitative polymerase chain reaction.

Minimal residual disease, or MRD, is an important prognostic indicator in childhood acute lymphoblastic leukemia. In ALL-IC-BFM 2002 study, we employed a standardized method of flow cytometry MRD monitoring for multiple centers internationally using uniformed gating, and determined the relevant MRD-based risk stratification strategies in our local patient cohort. We also evaluated a novel method of PCR MRD quantitation using peripheral blood plasma. For the bone marrow flow MRD study, patients could be stratified into 3 risk groups according to MRD level using a single time-point at day-15 (Model I) (I-A: <0.1%, I-B: 0.1-10%, I-C: >10%), or using two time-points at day-15 and day-33 (Model II) (II-A: day-15<10% and day-33<0.01%, II-B: day-15 ≥ 10% or day-33 ≥ 0.01% but not both, II-C: day-15 ≥ 10% and day-33 ≥ 0.01%), which showed significantly superior prediction of relapse (p = .00047 and <0.0001 respectively). Importantly, patients with good outcome (frequency: 56.0%, event-free survival: 90.1%) could be more accurately predicted by Model II. In peripheral blood plasma PCR MRD investigation, patients with day-15-MRD ≥ 10(-4) were at a significantly higher risk of relapse (p = 0.0117). By multivariate analysis, MRD results from both methods could independently predict patients' prognosis, with 20-35-fold increase in risk of relapse for flow MRD I-C and II-C respectively, and 5.8-fold for patients having plasma MRD of ≥ 10(-4). We confirmed that MRD detection by flow cytometry is useful for prognostic evaluation in our Chinese cohort of childhood ALL after treatment. Moreover, peripheral blood plasma DNA MRD can be an alternative where bone marrow specimen is unavailable and as a less invasive method, which allows close monitoring.

Surgical resection of relapse may improve postrelapse survival of patients with localized osteosarcoma.

BACKGROUND: Despite neoadjuvant chemotherapy and wide surgical ablation, 15% to 25% of patients with primary osteosarcoma will relapse (local recurrence or metastases). Neither chemotherapy nor radiation therapy alone will render a patient disease-free without concomitant surgical ablation of relapse. We prefer excision of relapse when possible. However, it is unclear whether excision enhances survival. QUESTIONS/PURPOSES: We therefore determined (1) onset, location, and treatments for relapse; (2) postrelapse disease-free survival of patients who underwent surgical ablation and those who did not; and (3) relapse-free interval between initial diagnosis and first relapse in survivors and in those who died of their disease. METHODS: We retrospectively reviewed 15 children who initially presented with localized, nonmetastatic extremity osteosarcoma and attained initial complete remission after neoadjuvant chemotherapy, wide local resection, postoperative chemotherapy, and subsequently developed disease relapse. Relapse occurred at a median of 28 months, although late relapse after 5 years occurred in three. We resected the recurrent tumor in nine patients and treated six nonoperatively. RESULTS: Seven of nine surgically treated patients had a postrelapse disease-free survival ranging from 3 to 14 years and an overall survival ranging from 7 to 16 years. Patients not surgically treated all died within 40 months of their relapse. The median relapse-free interval in patients who survived was longer 34 months (range, 17-152 months) as compared with 17 months (range, 7-40 months) in those who died of their disease. CONCLUSIONS: Our data confirm the importance of surgery in patients with relapsed osteosarcoma. Disease-free survival in patients with relapsed osteosarcoma is only possible if complete remission is attained. Patients with late relapse may have a better chance of survival. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Psychometric properties of the Chinese version of the Pediatric Quality Of Life Inventory 4.0 Generic Core scales among pediatric cancer patients.

BACKGROUND: The Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales are commonly used to assess health-related quality of life of healthy children and pediatric patients. Validation of the Generic Core Scales among Chinese pediatric cancer patients has not been reported in the literature. The scales can serve to measure different quality-of-life domains that are not captured by the PedsQL Cancer Module. OBJECTIVE: Psychometric properties of the Chinese version of the PedsQL 4.0 among pediatric cancer patients and their caretakers were examined. METHODS: The Generic Core Scales were administered to 335 pairs of pediatric cancer patients (aged 8-18 years) and their caretakers in Hong Kong. RESULTS: A 5-factor structure (physical, emotional, social, school-related cognitive function, and missed school) was identified in the patient and proxy versions of the scales using confirmatory factor analysis. Both versions of the total scale reported Cronbach α's of .90 or greater, with almost all subscales reporting α's of .70 or greater. Test-retest reliability at 2 weeks was acceptable (intraclass correlations ≥0.60) for a majority of subscales. Agreement between patients' and caretakers' ratings was medium. CONCLUSIONS: The scales demonstrated acceptable psychometric properties and construct validity. IMPLICATIONS FOR PRACTICE: This study validated the Chinese version of the Generic Core Scales among pediatric cancer patients and their caretakers, which supports the future use of the scales in clinical settings. The Generic Core Scales can also be supplementary to the PedsQL Cancer Module for measuring multiple domains of quality of life in cancer population.

Secreted-frizzled related protein 1 is a transcriptional repression target of the t(8;21) fusion protein in acute myeloid leukemia.

Secreted-frizzled related proteins (SFRPs) are modulators of the Wnt signaling pathway that is closely involved in normal and malignant hematopoiesis. Epigenetic deregulation of Wnt modulators leading to aberrant signaling has been reported in adult patients with acute myeloid leukemia (AML), but its occurrence in childhood patients with AML and the role of individual modulators are unclear. In this study, we examined SFRP1, SFRP2, SFRP4, and SFRP5 promoter methylation in 83 patients with AML (59 children and 24 adults) and found preferential SFRP1 methylation and mRNA down-regulation in the prognostically favorable subgroup of AML with t(8;21) translocation. Among the 4 genes, SFRP1 methylation independently predicted prolonged event-free and relapse-free survivals in childhood patients with nonacute promyelocytic leukemia with nonadverse cytogenetics. Mechanistically, we further demonstrated that RUNX1-ETO, the t(8;21) fusion product, specifically bound the SFRP1 promoter and repressed its transcription via a consensus RUNX binding site. In t(8;21)-leukemia cells, SFRP1 selectively inhibited canonical Wnt signaling and cellular proliferation that were associated with concomitant down-regulation of Wnt/ß-catenin target genes, including CCND1 and MYC. Taken together, we identified SFRP1 as a transcriptional repression target of the t(8;21) fusion protein and demonstrated a novel mechanism of Wnt activation in a specific subtype of AML.

Validation of the Chinese version of the Pediatric Quality of Life Inventory (PedsQL) Cancer Module.

OBJECTIVE: The psychometric properties of the Chinese version of the Pediatric Quality of Life Inventory (PedsQL) Cancer Module were investigated. METHODS: This instrument and the Generic Core Scales were administered to 359 pediatric patients with cancer (5-18 years) and 413 parents of such patients (2-18 years old). RESULTS: Seven and eight factors were, respectively, identified for the patient and parent versions. The Cronbach's alpha coefficients were respectively .89 and .92 for the total scale, and respectively .75-.90 and .76-.93 for the subscales of the patient and parent versions. Test-retest reliability coefficients exceeded .60 for most cases. The total/subscale scores of the Cancer Module significantly correlated with those of the Generic Core Scales. Some of the subscales could distinguish between on-treatment and off-treatment patients. CONCLUSIONS: The psychometric properties of the patient and parent versions of the Chinese PedsQL Cancer Module were found acceptable.

Initial presentation and management of osteosarcoma, and its impact on disease outcome.

OBJECTIVE: To evaluate the initial presenting symptoms and management of osteosarcoma in Hong Kong Chinese children, in relation to any possible impact on disease outcomes. DESIGN: Retrospective study. SETTING: A tertiary referral centre of bone cancer in a university teaching hospital in Hong Kong. PATIENTS: All children aged younger than 18 years with a diagnosis of osteosarcoma who received treatment from March 1994 to October 2005. RESULTS: A total of 51 children were studied. The median age of onset was 13 (range, 3-20) years; 61% were males. The tumours were located in the distal femur and proximal tibia, which accounted for 45% and 22% of the cases, respectively; 24% of patients had metastatic disease at presentation. Swelling (76%) and pain (90%) were the most common presenting complaints. Approximately one third of the patients had a preceding history of trauma. The median duration of initial symptoms to first medical consultation of any sort was 30 (range, 0-360) days. The median time from the first consultation to a definitive diagnosis was 21 (range, 0-350) days; 25% were diagnosed more than 52 days after presentation. Bonesetters were initially consulted by 37% of these patients. From presentation to diagnosis, the median duration was 61 (range, 4-361) days. Analysis of the duration of pre-diagnosis symptoms did not correlate significantly with the development of metastatic disease, response to chemotherapy, feasibility of limb salvage surgery, relapse rates, or survival rates. CONCLUSIONS: In Hong Kong, initial consultation to bonesetters was common. A relatively long delay in between symptom onset and diagnosis of osteosarcoma was encountered. The public and medical practitioners should be made aware of this disease, especially in adolescents.

Long-term effects of pamidronate in thalassemic patients with severe bone mineral density deficits.

Osteoporosis is a common complication in thalassemia major (TM). Our previous study demonstrated severe bone mineral density (BMD) deficits at spine and hip in 62 and 35% of TM patients. This study assessed the effects of different treatments (calcium, vitamin D and bisphosphonate) on patients' BMD, which was measured at baseline and after 3-year treatments by dual energy X-ray absorptiometry (DEXA). Twenty-one untreated patients, 11 patients on calcium/vitamin D and seven patients on additional pamidronate, were recruited. They were comparable for gender (p = 0.630) and serum ferritin levels (p = 0.412). The median BMD Z-scores at lumbar spine and left hip improved only in patients with standard plus pamidronate treatments (baseline: -3.01 and -3.05, end-of-study: -2.12 and -2.09; p = 0.018 and 0.028, respectively). In contrast, BMD Z-scores at hip worsened in untreated patients (p = 0.034). In conclusion, long-term improvement in BMD in TM patients was observed with bisphosphonate but not calcium and vitamin D treatment.

Haematopoietic stem cell transplantation for thalassaemia in Chinese patients.

Beta thalassaemia major is a common hereditary haematological disease in southern Chinese. Advances in transfusion and iron chelation improve survival but haematopoietic stem cell transplantation (HSCT) is still the only curative treatment. Due to repeated blood transfusion and iron overload, thalassaemia patients undergoing HSCT are at a higher risk of graft rejection and transplant-related mortality. The prognostic factors identified to be affecting transplant outcome include hepatomegaly, hepatic fibrosis, and compliance to chelation therapy. Patients can be classified into three classes and conditioning regimens are modified according to the risk. Early stage patients have 85 to 90% chance of disease-free survival, whereas advance stage only has 60% disease-free survival. Mixed chimerism is common after HSCT but majority have satisfactory erythropoiesis without need for further transfusion. Sibling cord blood and bone marrow transplantation has similar outcome. Recently alternative donor transplant has been performed in patients without human leukocyte antigen (HLA)-identical siblings. The result of unrelated-donor bone marrow transplantation is in general inferior but extended HLA matching may improve outcome. The use of unrelated cord blood transplant from a single-centre study showed promising result. The survivors require iron depletion to remove excessive iron store and some may require hormonal replacement therapy. Most of the patients have good quality of life after successful HSCT.

Haemophagocytic lymphohistiocytosis in Hong Kong children.

Haemophagocytic lymphohistiocytosis is a rare but potentially fatal disease. Diagnosing this disease may be difficult and is often delayed because the clinical presentation mimics other conditions like severe sepsis, hepatic failure and malignancies. We reviewed the clinical presentations, response to treatment, and outcomes of children diagnosed with haemophagocytic lymphohistiocytosis from 1991 to 2006 in a Hong Kong tertiary paediatric haematology centre. All patients had typical presentations with prolonged fever, organomegaly, and pancytopaenia. Six children had hepatic dysfunction and two had neurological symptoms. The median time from disease onset to diagnosis was 21 days. Elevated serum ferritin levels and evidence of haemophagocytosis in bone marrow examinations aided diagnosis. The overall mortality was 57%. Three patients who presented in the first few years studied had relatively long lag times between disease onset and definitive treatment; all died of active disease. Three patients diagnosed more recently were given timely treatment using the haemophagocytic lymphohistiocytosis-94 protocol of etoposide and dexamethasone, with or without cyclosporin. All three achieved remission, but two had a recurrence and one died during the recurrence.

Transcriptional repression of the RUNX3/AML2 gene by the t(8;21) and inv(16) fusion proteins in acute myeloid leukemia.

RUNX3/AML2 is a Runt domain transcription factor like RUNX1/AML1 and RUNX2/AML3. Regulated by 2 promoters P1 and P2, RUNX3 is frequently inactivated by P2 methylation in solid tumors. Growing evidence has suggested a role of this transcription factor in hematopoiesis. However, genetic alterations have not been reported in blood cancers. In this study on 73 acute myeloid leukemia (AML) patients (44 children and 29 adults), we first showed that high RUNX3 expression among childhood AML was associated with a shortened event-free survival, and RUNX3 was significantly underexpressed in the prognostically favorable subgroup of AML with the t(8;21) and inv(16) translocations. We further demonstrated that this RUNX3 repression was mediated not by P2 methylation, but RUNX1-ETO and CBFbeta-MYH11, the fusion products of t(8;21) and inv(16), via a novel transcriptional mechanism that acts directly or indirectly in collaboration with RUNX1, on 2 conserved RUNX binding sites in the P1 promoter. In in vitro studies, ectopically expressed RUNX1-ETO and CBFbeta-MYH11 also inhibited endogenous RUNX3 expression. Taken together, RUNX3 was the first transcriptional target found to be commonly repressed by the t(8;21) and inv(16) fusion proteins and might have an important role in core-binding factor AML.

Autoimmune hypothyroidism after unrelated haematopoietic stem cell transplantation in children.

We describe two pediatric patients who developed autoimmune hypothyroidism 2 years after unrelated allogeneic hematopoietic stem cell transplantation. The causes of post-transplantation autoimmune hypothyroidism are probably multiple. In these two patients, the presence of chronic graft-versus-host disease may be the most significant contributing factor.

HLA-B67 may be a male-specific HLA marker of susceptibility to relapsed childhood ALL in Hong Kong Chinese and HLA-A33 or HLA-B17 signifies a higher presentation leukocytosis: A retrospective analysis on 53 transplant candidates (1989-2003).

We performed a retrospective analysis on the human leukocyte antigen (HLA) data of 53 consecutive Chinese patients with high-risk childhood acute lymphoblastic leukemia (ALL) diagnosed from 1989 to 2003. A significantly higher frequency of HLA-B67 in the male relapse group of patients [OR, 23.08; 95% CI, 5.31-100.36; p = 0.0042; for statistical significance after Bonferroni correction (Bc) p (Bc) < 0.0083] was identified after Bonferroni correction. Although not surviving the Bonferroni correction, gender effects on the association were also observed with HLA-A11, HLA-A32, HLA-A33, and HLA-B22, which were however more prevalent in the female patients and particularly those developing relapse. Two patients with HLA-A29 and HLA-B7 revealed significantly shortened survivals, suggestive of their potential prognostic impacts. Notably, for the first time, we found a significant correlation of leukocyte count with HLA types, where HLA-A33 (p = 0.006) or HLA-B17 (p < 0.001) signifies higher leukocytosis at presentation. Taken together, our findings support the involvement of HLA in Chinese high-risk childhood ALL.

Risk factors and clinical consequences of human herpesvirus 7 infection in paediatric haematopoietic stem cell transplant recipients.

Human herpesvirus 7 (HHV-7) is the least studied beta-herpesvirus in transplant settings. This prospective study examined the activity of HHV-7 during the first 12 weeks post-stem cell transplant in 59 paediatric patients. The presence of HHV-7, human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6) in blood was monitored weekly by a multiplex nested polymerase chain reaction. Overall, 33 (55.9%) patients had one or more surveillance blood sample(s) positive for HHV-7. In contrast to HCMV and HHV-6, no obvious peak time of reactivation was observed for HHV-7. The occurrence of HHV-7 DNAaemia showed a significant negative association with HHV-6 (P=0.022), but with no association with HCMV. A significant higher positive rate for HHV-7 was found in autologous versus allogeneic (P=0.002), and in peripheral blood versus umbilical cord/marrow (P<0.001) transplant. Acyclovir had no effect, whereas ganciclovir was associated with a lower rate of HHV-7 reactivation (P=0.009). One patient died of HHV-7 associated brain stem encephalitis. The administration of colony stimulating factor, occurrence of acute graft versus host disease, time to neutrophil and platelet engraftment showed no significant association with the occurrence of HHV-7 DNAaemia.

Genetic variation of glycoproteins B and H of human herpesvirus 7 in Hong Kong.

Glycoprotein B (gB) and glycoprotein H (gH) of human herpesvirus 7 (HHV-7) are believed to play an important role in virus entry and as targets for host immune response. This study examined the genetic diversity of these glycoproteins among 90 HHV-7 isolates collected from different individuals in Hong Kong. Overall, both the gB and gH genes were found to be highly conserved. Nucleotide polymorphism was detected only at four positions of the gB-encoding region, and all of these were synonymous substitutions. Most (97.8%) Hong Kong isolates were of gB allele group C. Two isolates collected from a Pakistani family showed a novel sequence pattern that did not match known gB allele groups. This sequence pattern was detected consistently from serial samples collected from the same individual, indicating a stable genetic entity. The gH-encoding region exhibited nucleotide polymorphism at six positions. Three of these were nonsynonymous substitutions (codon 271 Lys --> Gln, codon 308 Gly --> Glu, codon 397 Asn --> Tyr). Most (84.4%) Hong Kong isolates were of the gH allele group B, and all others were of the gH allele group C. These data indicate the possibility of using gB or gH alleles as markers for studying world-wide population movements and genetics.