Background. Radiotherapy has been utilized for metastatic and recurrent osteosarcoma and Ewing sarcoma (ES), in order to provide palliation and possibly prolong overall or progression-free survival. Stereotactic body radiotherapy (SBRT) is convenient for patients and offers the possibility of increased efficacy. We report our early institutional experience using SBRT for recurrent and metastatic osteosarcoma and Ewing sarcoma. Methods. We reviewed all cases of osteosarcoma or ES treated with SBRT between 2008 and 2012. Results. We identified 14 patients with a total of 27 lesions from osteosarcoma (n = 19) or ES (n = 8). The median total curative/definitive SBRT dose delivered was 40 Gy in 5 fractions (range, 30–60 Gy in 3–10 fractions). The median total palliative SBRT dose delivered was 40 Gy in 5 fractions (range, 16–50 Gy in 1–10 fractions). Two grade 2 and 1 grade 3 late toxicities occurred, consisting of myonecrosis, avascular necrosis with pathologic fracture, and sacral plexopathy. Toxicity was seen in the settings of concurrent chemotherapy and reirradiation. Conclusions. This descriptive report suggests that SBRT may be a feasible local treatment option for patients with osteosarcoma and ES. However, significant toxicity can result, and thus systematic study is warranted to clarify efficacy and characterize long-term toxicity.

Here we report the isolation of a murine model for heritable T cell lymphoblastic leukemia/lymphoma (T-ALL) called Spontaneous dominant leukemia (Sdl). Sdl heterozygous mice develop disease with a short latency and high penetrance, while mice homozygous for the mutation die early during embryonic development. Sdl mice exhibit an increase in the frequency of micronucleated reticulocytes, and T-ALLs from Sdl mice harbor small amplifications and deletions, including activating deletions at the Notch1 locus. Using exome sequencing it was determined that Sdl mice harbor a spontaneously acquired mutation in Mcm4 (Mcm4D573H). MCM4 is part of the heterohexameric complex of MCM2–7 that is important for licensing of DNA origins prior to S phase and also serves as the core of the replicative helicase that unwinds DNA at replication forks. Previous studies in murine models have discovered that genetic reductions of MCM complex levels promote tumor formation by causing genomic instability. However, Sdl mice possess normal levels of Mcms, and there is no evidence for loss-of-heterozygosity at the Mcm4 locus in Sdl leukemias. Studies in Saccharomyces cerevisiae indicate that the Sdl mutation produces a biologically inactive helicase. Together, these data support a model in which chromosomal abnormalities in Sdl mice result from the ability of MCM4D573H to incorporate into MCM complexes and render them inactive. Our studies indicate that dominantly acting alleles of MCMs can be compatible with viability but have dramatic oncogenic consequences by causing chromosomal abnormalities.

There is practice variation among pediatric gastroenterologists in assessment of immunizations in patients with inflammatory bowel disease, including the specific vaccines assessed, and timing and method of assessment. Inability to coordinate care, access immunization records, and offer vaccines through their medical practice are barriers to adhering to immunization guidelines.

Central nervous system primitive neuroectodermal tumors (CNS PNETs) predominantly occur in children and rarely in adults. Because of the rarity of this tumor, its outcomes and prognostic variables are not well characterized. The purpose of this study was to evaluate clinical outcomes and prognostic factors for children and adults with CNS PNET. The records of 26 patients (11 children and 15 adults) with CNS PNET from 1991 to 2011 were reviewed retrospectively. Disease-free survival (DFS) and overall survival (OS) were estimated with the Kaplan-Meier method, and relevant prognostic factors were analyzed. For the cohort, both the 5-year DFS and the OS were 46 %. For pediatric patients, the 5-year DFS was 78 %; for adult patients, it was 22 % (P = 0.004). Five-year OS for the pediatric and adult patients was 67 and 33 %, respectively (P = 0.07). With bivariate analysis including chemotherapy regimen (high dose vs. standard vs. nonstandard) or risk stratification (standard vs. high) and age, the increased risk of disease recurrence in adults persisted. A nonsignificant tendency toward poorer OS in adult patients relative to pediatric patients also persisted. High-dose chemotherapy with stem cell rescue was associated with a statistically significant improvement in OS and a tendency toward improved DFS, although the findings were mitigated when the effect of age was considered. Local recurrence was the primary pattern of treatment failure in both adults and children. Our results suggest that adult patients with CNS PNETs have inferior outcomes relative to the pediatric cohort. Further research is needed to improve outcomes for CNS PNET in populations of all ages.