Human leukocyte antigen disparities reduce relapse after hematopoietic stem cell transplantation in children with juvenile myelomonocytic leukemia: A single-center retrospective study from China.

BACKGROUND: HSCT is the only proven curative therapy for JMML. Matching donor and recipient HLA alleles is considered optimal to reduce the risk of GVHD after HSCT but is not always possible. Only a limited number of studies have compared the influence of HLA disparities on HSCT outcomes for patients with JMML. METHODS: We conducted a retrospective study among 47 children with JMML who received related or unrelated unmanipulated HSCT (March 2010-October 2018). Among our participants, 27 (57.4%) donor-recipient pairs had 0-1 HLA disparities (Group 1: HLA-matched or ≤1 allele/antigen mismatch donor) and 20 (42.6%) had ≥2 HLA disparities (Group 2: 2-3 mismatched/haploidentical donors). RESULTS: The median follow-up period was 26.0 months (range: 1-105 months), and the 5-year probabilities of DFS and RI for the whole cohort were 54.6 ± 7.7% and 34.8 ± 15.0%, respectively. Compared to Group 1, Group 2 patients had a significantly lower RI (5.3 ± 10.5% vs 55.5 ± 20.9%, P Ë‚ .001), though similar rates of grade II-IV acute GVHD (60.0 ± 22.4% vs 33.3 ± 18.2%, P = .08), grade III-IV acute GVHD (25.0 ± 19.5% vs 7.4 ± 10.1%, P = .08), chronic GVHD (30.0 ± 20.9% vs 34.9 ± 18.8%, P = .85), NRM (20.0 ± 18.0% vs 3.9 ± 7.7%, P = .07), and DFS (74.4 ± 9.9% vs 41.3 ± 10.0%, P = .08). CONCLUSIONS: Disease relapse remains the major cause of treatment failure in JMML patients, especially in patients receiving HLA-matched and limited HLA-mismatched HSCT. Our findings suggest that donor-recipient HLA disparities may improve the outcome of HSCT in children with JMML.

Renal tumor in developing countries: 142 cases from a single institution at Shanghai, China.

BACKGROUND: The clinical management of children with renal tumors including Wilms' tumor, clear cell sarcoma, rhabdoid tumor and other renal tumors in our center was designed according to the National Wilms' Tumor Study Group protocols. METHODS: A total of 142 consecutive patients who had been diagnosed as having renal tumors at Shanghai Children's Medical Center were reviewed retrospectively in the period of December 1998 and September 2012. Diagnosis and treatment were decided by a multidisciplinary team including oncologists, surgeons, pathologists and sub-specialized radiologists. RESULTS: The median age of the patients at the time of diagnosis was 27 months. The tumor stages of the patients were as follows: stage I 24.6%, stage II 23.2%, stage III 32.3%, stage IV 14.1%, and stage V 5.6%. Favorable histology was diagnosed in 80.3%, anaplasia in 4.2%, clear cell sarcoma in 9.8%, rhabdoid tumor in 4.9%, and other renal tumors in 0.7% of the patients. The event-free and overall 5-year survival rates were 80% and 83%, respectively. Tumor relapse and progress was seen in 25 patients (17.6%). The median relapse time was 6 months (range: 2-37 months). Seven relapsing patients were retreated and four of them got second complete remission (three in stage II, one in stage I). CONCLUSION: A multi-disciplinary team work model is feasible in developing countries, and the renal tumors protocols basically from developed countries are safe in developing countries.

Minimal residual disease is a prognostic marker for neuroblastoma with bone marrow infiltration.

OBJECTIVE: This pilot study focused on whether flow cytometry (FCM) detection of minimal residual disease in bone marrow (BM) could predict the outcome of patients with advanced neuroblastoma (NB). PATIENTS AND METHODS: Fifty-seven stage 4 NB patients with BM infiltration were enrolled in this study. All of them received NB-2001 protocol. BM samples were examined for tumor cell contamination by both morphology and FCM with CD45-FITC/CD81-PE/CD56-PECy5 monoclonal antibodies cocktail at diagnosis and after 4 courses of chemotherapy. RESULTS: BM samples of all patients were positive at diagnosis by FCM, and samples from 30 patients became negative after 4 courses of chemotherapy, 10 patients relapsed (33.3%) in mean 45.5 months, range 7 to 69. Another 27 patients remained positive, and 20 of them relapsed (74.1%) in mean 24.2 months, range 8 to 48. There was a statistically significant difference in event-free survival between the 2 groups (P = 0.002). CONCLUSIONS: Persistence of minimal residual disease in BM may work as a chemotherapy response marker and predict the prognosis in advanced NB.

The cultivation and identification of tumor stem cells from neuroblastoma derived tumor spheres.

BACKGROUND AND OBJECTIVE: Since the proposal of the tumor stem cell hypothesis, considerable interest has been devoted to the isolation and purification of tumor stem cells. Tumor stem cell enrichment from primary tumor derived cell spheres has been demonstrated in specific, serum-free media. This goal of this study is to establish a method of cultivating floating tumor spheres from neuroblastoma cells and to confirm that neuroblastoma spheres are rich in tumor stem cells. METHODS: Bone marrow aspirates were obtained from pediatric patients diagnosed with stage IV neuroblastoma. Primary tumor cells were isolated and cultivated in serum-free, stem cell-selective medium. Single sphere-forming cells were cultivated under serum-free conditions; their cloning efficiency and monoclonal tumor sphere formation rates were calculated. The expression of stem cell marker genes Oct-4 and Bmi-1 was detected by RT-PCR in sphere-forming cells and parental neurolastoma cells. Sphere-forming cells were injected into the armpit of nude mice with subsequent assessment for tumor growth. Sphere-forming cells were cultivated in differentiation medium containing 5 µmol/L 13-cis retinoic acid; changes in cell morphology were observed. RESULTS: Neuroblastoma cells formed non-adherent neurospheres under serum-free, stem cell-selective conditions after a period of 4 to 6 days. A single cell dissociated from a neurosphere could reform a monoclonal sphere; cloning efficiency and monoclonal sphere formation rates were 55.3% and 26.3%, respectively. RT-PCR results revealed heightened tumor sphere expression of Oct-4 and Bmi-1 as compared with parental tumor cells. Fourteen days after injection of 10(4) sphere-forming cells into nude mice, a neuroblastoma xenograft formed. Treatment of sphere-forming cells with 13-cis retinoic acid induced a gradual differentiation to neuronal cell morphology. CONCLUSIONS: Neuroblastoma derived tumor spheres enrich tumor stem cells and the cultivation of primary neuroblastoma cells in serum-free, stem cell-selective medium is an effective method to dissociate and purify tumor stem cells in vitro.

Results of RS-99 protocol for childhood solid tumors.

BACKGROUND: Little was known about the therapeutic result of rhabdomyosarcomas (RMSs) and other malignant tumors until the end of the last century in China. Very few prospective clinical research results have been reported. We designed a RS-99 protocol under close cooperation of a multidisciplinary team including surgeons, radiologists, pathologists, and pediatric oncologists at Shanghai Children's Medical Center. This study aimed to improve the prognosis of childhood solid tumors and analyze the results of different tumors with the same protocol, including RMSs, the Ewing sarcoma family of tumors (ESFTs), and ex-cranial germ cell tumors (GCTs). METHODS: Sixty-six patients with malignant solid tumors [RMS (n=30), GCT (n=22), and ESFT (n=14)] were enrolled on the RS-99 protocol from October 1998 to October 2006. They were 34 girls and 32 boys aged 9 to 194 months. The protocol involved surgery, radiotherapy and chemotherapy which included VCP (vincristine, cisdiaminedichloroplatinum, and cyclophosphamide) and IEV (etoposide, vincristine and ifosfamide) for the low-risk group, AVCP (adriamycin, vincristine, cisdiaminedichloroplatinum, and cyclophosphamide) and IEV for the intermediate-risk group and high-risk group. Peripheral blood stem cell transplantation was suggested for the high-risk group. Radiotherapy was only given for RMS and ESFT. Differences in survival between the groups were determined by comparison of entire survival curves and tested by the Kaplan-Meier method and the log-rank tests. RESULTS: The 5-year event-free survival (EFS) for the whole group (RMS, ESFT and GCT) was 60%. The 5-year EFS for children with RMS was 35% (95% CI 16-54), GCT was 79% (95% CI 70-88) and ESFT was 72% (95% CI 58-86). The 5-year EFS showed that the patients with RMS in the retroperitoneum-pelvis did not have a better result than those with tumors in other sites (P=0.604). The histological classification of RMS exerted prognostic influence on the estimated 5-year EFS (P=0.04). Tumor stage and risk group were also contributive to prognosis (P=0.008). For GCT patients, the primary sites of tumors and their histological classification did not influence the therapeutic result (P=0.814). The 5-year EFS was 100% in stage I and II versus 62% in stage III and IV patients (P=0.02). Because of the small number of patients, we did not analyze the prognostic factors for patients with ESFT. No organ failure or functional impairment occurred in the patients enrolled in the RS-99 protocol. One ESFT patient developed a second cancer. CONCLUSIONS: The RS-99 protocol is well tolerated and is reasonable for the 3 different tumors. Risk-based grouping protocol design is needed and the protocol for high risk RMS should be revised.

Prognostic influence of minimal residual disease detected by flow cytometry and peripheral blood stem cell transplantation by CD34+ selection in childhood advanced neuroblastoma.

OBJECTIVE: To determine whether neuroblastoma (NB) minimal residual disease (MRD) in bone marrow (BM) detected by flow cytometry could predict prognosis and whether tumor cell purging by CD34(+) cell selection prior to transplantation will impact on disease-free survival. METHODS: NB MRD in BM was evaluated by flow cytometry with CD45-FITC-/CD81-PE+/CD56-PECy5+ monoclonal antibodies cocktail. Peripheral blood stem cell (PBSC) was enriched via positive CD34(+) cell selection by magnetic-activated cell separation system (MACS). RESULTS: Eleven of 31 patients with CD45(-)/CD81+/CD56+ cells by flow cytometry at diagnosis became negative after an average of four courses of chemotherapy. All 11 patients remained alive without evidence of disease. Thirteen of the 20 patients with positive MRD relapsed and 1 patient died from disease (mean 25.8 months). There was a significant difference between these two groups. MRD in BM was tested before PBSC transplantation (PBSCT) for 19 NB patients. Fourteen was negative, 4 of them relapsed and 10 patients remained alive without evidence of disease. Another 5 patients with positive MRD, all of them relapsed (mean 17 months after PBSCT) with a significant difference between these two groups. Fourteen of 19 PBSC were purged with CD34(+) selection procedure. Six of 14 relapsed (mean 18.43 months after PBSCT). Five patients did not purge for CD34(+) selection, and 3 of them relapsed with no significant difference between these two groups. CONCLUSIONS: Positive MRD in BM after an average of four courses of chemotherapy and before PBSCT is an unfavorable factor for stage IV NB. CD34(+) selection purging for PBSCT may not improve the prognosis for children with neuroblastoma in advanced stage.