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To extract the high-quality DEM in complicated mountain areas, a DEM fusion method for ascending and descending orbit StereoSAR DEMs considering Synthetic Aperture Radar (SAR) echo intensity is proposed. After the analysis for the influence of terrain features and SAR side-looking imaging characteristics on radar echo intensity and DEM accuracy, four TerrasAR-X images with the stripmap mode and the 3 m spatial resolution covering a certain area of Maoxian County, Sichuan Province, China, was selected as the experimental area. StereoSAR technology was used to extract the ascending orbit StereoSAR DEM and the descending orbit StereoSAR DEM, respectively, and the corresponding radar echo intensity map was calculated. Then, while comparing the radar echo intensity corresponding to the same point position, DEM fusion was carried out, and the accuracy of DEM before and after the fusion was analyzed with the ground points measured by GNSS-RTK as reference data. Finally, a high-quality DEM with a 3 m spatial resolution in the experimental area was obtained. The DEM accuracy was improved on all slopes, and the mean absolute deviation (MAD) improved to 4.798 m, the standard deviation (SD) improved to 6.087 m and the LE90 improved to 40.48 m. The experimental results indicate that the fusion method of high-resolution ascending and descending orbit StereoSAR DEMs considering SAR echo intensity can effectively extract DEM with high accuracy and reliability, which can provide technical support for obtaining high-quality terrain information in similar areas.

OBJECTIVE: To study the clinical significance of minimal residual disease (MRD) in B-lineage acute lymphoblastic leukemia (B-ALL) pediatric patients with different fusion gene backgrounds. METHODS: A retrospective analysis was performed on the medical data of 441 B-ALL children who were treated from January 2008 to April 2015. Among the 441 children, 336 had negative fusion gene, 79 had positive ETV6-RUNX1 fusion gene, and 26 had positive E2A-PBX1 fusion gene. Flow cytometry was used to detect MRD, and the influence of MRD on day 15 (TP1), day 33 (TP2), and week 12 (TP3) of induction therapy on prognosis was analyzed. RESULTS: In patients with negative fusion gene, the positive MRD group had significantly lower overall survival (OS) rate and event-free survival (EFS) rate (P < 0.05) and significantly higher recurrence rate and mortality rate at TP1, TP2, and TP3, compared with the negative MRD group (P < 0.05). In patients with positive ETV6-RUNX1, the positive MRD group had significantly lower OS and EFS rates (P < 0.05) and significantly higher recurrence rate and mortality rate (P < 0.05) than the negative MRD group only at TP1. In patients with positive E2A-PBX1, there were no significant differences in the OS rate, recurrence rate, and mortality rate between the positive and negative MRD groups at TP1, TP2, and TP3 (P > 0.05). CONCLUSIONS: MRD has the most definite prognostic significance in pediatric B-ALL patients with negative fusion gene, while it has unsatisfactory prognostic significance in those with positive ETV6-RUNX1 or positive E2A-PBX1.

Acute lymphoblastic leukemia (ALL) is a common pediatric cancer. The second malignant neoplasms (SMNs) in long-term survivors of pediatric ALL are relatively rare. Herein we report a 10-year-old girl who was diagnosed as primitive neuroectodermal tumor (PNET) 5 years after the initial diagnosis of ALL with radiotherapy-free treatment. PNET is an exceedingly rare neoplasm in SMNs of survivors of childhood ALL. It is predisposed to be misdiagnosed and the pathogenesis is unclear. The outcome is poor. Long-term follow-up is necessary for the survival children of ALL.

OBJECTIVE: To compare the efficacy of the CAMS-2005 and CAMS-2009 regimens in treating children with non-core binding factor acute myeloid leukemia (non-CBF AML) and to study the prognosis factors. METHODS: A total of 161 children who were initially diagnosed with non-CBF AML from April 2005 to December 2015 were enrolled as study subjects, and were divided into a CAMS-2005 regimen group (n=52) and a CAMS-2009 regimen group (n=109) according to the chemotherapy regimen provided. The efficacy was retrospectively compared between the two groups. RESULTS: The complete remission (CR) rate at the first course of treatment was higher in the CAMS-2009 regimen group than that in the CMAS-2005 regimen group (63.3% vs 46.2%; P < 0.05). There were no significant differences between the two groups in treatment-related mortality rate (11.9% vs 17.3%), recurrence rate (27.5% vs 28.8%), and three-year overall survival (OS) rate (44%±5% vs 28%±6%) (P > 0.05). Children who achieved CR at the first course of treatment had significantly higher OS and event-free survival rates than those who did not achieved CR (P < 0.01). CONCLUSIONS: The CAMS-2009 regimen is superior to the CAMS-2005 regimen in improving the CR rate in children with non-CBF AML after induction treatment. Whether CR is achieved at the first course of treatment can affect the OS rate of children with non-CBF AML.

OBJECTIVE: To study the association of platelet level at diagnosis with prognosis in children with acute lymphoblastic leukemia (ALL). METHODS: A total of 892 children with ALL who underwent chemotherapy with the CCLG-ALL 2008 regimen were enrolled. According to the platelet count at diagnosis, these children were divided into normal platelet count group (platelet count ≥ 100×10(9)/L; n=263) and thrombocytopenia group (platelet count < 100×10(9)/L; n=629). The thrombocytopenia group was further divided into (50- < 100)×10(9)/L (n=243), (20- < 50)×10(9)/L (n=263), and < 20×10(9)/L (n=123) subgroups. The association of clinical features (sex, age, immunophenotype, and molecular biology) with event-free survival (EFS) and overall survival (OS) was analyzed. RESULTS: Compared with the thrombocytopenia group, the normal platelet count group had significantly lower positive rate of MLL gene rearrangement and recurrence rate (P < 0.05), as well as a significantly higher 10-year EFS rate (P < 0.05). There was no significant difference in 10-year OS between the two groups (P > 0.05). The normal platelet count group still had a significantly higher 10-year EFS rate than the thrombocytopenia group after the children with MLL gene rearrangement were excluded (P < 0.05), and there was still no significant difference in 10-year OS between the two groups (P > 0.05). The < 20×10(9)/L subgroup had significantly lower 10-year EFS and OS rates than the normal platelet count group, the (50- < 100)×10(9)/L subgroup, and the (20- < 50)×10(9)/L subgroup (P < 0.05). After the children with MLL gene rearrangement were excluded, the < 20×10(9)/L subgroup still had significantly lower 10-year EFS and OS rates than the normal platelet count group, the (50- < 100)×10(9)/L subgroup, and the (20- < 50)×10(9)/L subgroup (P < 0.05). CONCLUSIONS: ALL children with MLL gene rearrangement often have the clinical manifestation of thrombocytopenia. Platelet level at diagnosis is associated with the prognosis of ALL children. The children with normal platelet count have a low recurrence rate and good prognosis, and those with a platelet count of < 20×10(9)/L have the worst prognosis.

To investigate the safety and efficacy of autologous peripheral blood hematopoietic stem cell transplantation (auto-PBHSCT) using modified BU/CY conditioning regimen for young AML patients of low and middle risk in the first complete remission (CR1).Ten young AML patients of low and middle risk who did not want to accept allogeneic hematopoietic stem cell transplantation（allo-HSCT）and underwent auto-PBHSCT in CR1 during May 2013 to December 2016 were retrospectively analyzed. From 3 months after auto-PBHSCT, the maintenance therapy with interleukin-2 (IL-2) or IL-2 combined with histamine dihydrochloride was performed for these patients in the next 18 months. The side effects of the conditioning regimen, hematopoietic recovery time, transplant-related mortality (TRM) within 100 days and 1 year after auto-PBHSCT, relapse rate, leukemia-free survival (LFS) rate at 2 years and 3 years, overall survival (OS) were evaluated at 3 years and 4 years.Gastrointestinal side effects were the major non-hematologic toxicity reaction, among which, 7 cases relatively mild and 3 cases displayed moderate, just one case suffered from severe reaction. In 4 cases, the mild liver damage occurred, but no hemorrhagic cystitis occurred. All the patients experienced different kinds of infection, including 5 cases of bloodstream infection, 2 cases of gastrointestinal infection, 3 cases of crissum infection and 2 cases of oral infection. The myeloablative effect occurred in all ten patients. The median times for absolute neutrophil count (ANC)0.5×10Modified BU/CY as conditioning regimen for auto-PBHSCT can achieve the myeloablative effect without raising TRM and obtain good LFS and OS. As for young AML patients without high risk, it is a valuable therapeutic option, especially for those lacking the chance of allo-HSCT.应用改良BU/CY方案预处理联合自体外周血造血干细胞移植治疗青年中、低危急性髓系白血病疗效观察.观察青年中、低危急性髓系白血病（AML）在第1次完全缓解期（CR1）接受白消安（BU）/环磷酰胺（CY）改良方案预处理后行自体外周血造血干细胞移植（auto-PBHSCT）的安全性及疗效。.采用回顾性分析方法探讨改良BU/CY预处理联合auto-PBSCT的疗效。本院2013年5月至2016年12月期间10例青年中、低危AML患者，无异基因干细胞移植条件、CR1期接受以改良的BU/CY方案预处理联合auto-PBSCT，移植后3个月开始白介素-2（IL-2）或IL-2+二盐酸组胺维持治疗18个月。观察预处理方案的毒副作用、造血恢复时间、移植后100 d及1年内死亡率、复发率、2年及3年无白血病生存率（LFS）、3年及4年总生存率（OS）。.常见的非血液学毒性反应为胃肠道反应（轻度7例、中度3例、重度1例）、轻度肝损害（4例）、出血性膀胱炎0例、轻中度感染10例（血流感染5例，肠道感染2例，肛周感染3例，口腔感染2例）。患者均达到清髓效果，中性粒细胞（ANC）0.5×10改良的BU/CY+auto-PBSCT治疗模式可达到清髓目的，对青年中、低危AML疗效明确，移植相关死亡率低，LFS及OS时间较长，可作为无异基因造血干细胞移植条件患者的另一个治疗选择。.

Acute lymphoblastic leukemia (ALL) is a common pediatric cancer. The second malignant neoplasms (SMNs) in long-term survivors of pediatric ALL are relatively rare. Herein we report a 10-year-old girl who was diagnosed as primitive neuroectodermal tumor (PNET) 5 years after the initial diagnosis of ALL with radiotherapy-free treatment. PNET is an exceedingly rare neoplasm in SMNs of survivors of childhood ALL. It is predisposed to be misdiagnosed and the pathogenesis is unclear. The outcome is poor. Long-term follow-up is necessary for the survival children of ALL.