Sarcomas are heterogeneous and clinically challenging soft tissue and bone cancers. Although constituting only 1% of all human malignancies, sarcomas represent the second most common type of solid tumors in children and adolescents and comprise an important group of secondary malignancies. More than 100 histological subtypes have been characterized to date, and many more are being discovered due to molecular profiling. Owing to their mostly aggressive biological behavior, relative rarity, and occurrence at virtually every anatomical site, many sarcoma subtypes are in particular difficult‐to‐treat categories. Current multimodal treatment concepts combine surgery, polychemotherapy (with/without local hyperthermia), irradiation, immunotherapy, and/or targeted therapeutics. Recent scientific advancements have enabled a more precise molecular characterization of sarcoma subtypes and revealed novel therapeutic targets and prognostic/predictive biomarkers. This review aims at providing a comprehensive overview of the latest advances in the molecular biology of sarcomas and their effects on clinical oncology; it is meant for a broad readership ranging from novices to experts in the field of sarcoma.

Pediatric high-grade glioma (pHGG) and diffuse intrinsic pontine gliomas (DIPGs) are aggressive pediatric brain tumors in desperate need of a curative treatment. Oncolytic virotherapy is emerging as a solid therapeutic approach. Delta-24-RGD is a replication competent adenovirus engineered to replicate in tumor cells with an aberrant RB pathway. This virus has proven to be safe and effective in adult gliomas. Here we report that the administration of Delta-24-RGD is safe in mice and results in a significant increase in survival in immunodeficient and immunocompetent models of pHGG and DIPGs. Our results show that the Delta-24-RGD antiglioma effect is mediated by the oncolytic effect and the immune response elicited against the tumor. Altogether, our data highlight the potential of this virus as treatment for patients with these tumors. Of clinical significance, these data have led to the start of a phase I/II clinical trial at our institution for newly diagnosed DIPG (NCT03178032).

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We have analyzed the regulation and expression of ASPP members, genes implicated in the regulation of the apoptotic function of the TP53 tumor-suppressor gene, in acute lymphoblastic leukemia (ALL). Expression of ASPP1 was significantly reduced in ALL and was dependent on hypermethylation of the ASPP1 gene promoter. Abnormal ASPP1 expression was associated with normal function of the tumor-suppressor gene TP53 in ALL. The analyses of 180 patients with ALL at diagnosis showed that the ASPP1 promoter was hypermethylated in 25% of cases with decreased mRNA expression. Methylation was significantly higher in adult ALL vs childhood ALL (32 vs 17%, P ¼ 0.03) and T-ALL vs B-ALL (50 vs 9%, P ¼ 0.001). Relapse rate (62 vs 44%, P ¼ 0.05) and mortality (59 vs 43%, P ¼ 0.05) were significantly higher in patients with methylated ASPP1. DFS and OS were 32.8 and 33.7% for patients with unmethylated ASPP1 and 6.1 and 9.9% for methylated patients (Po0.001 y Po0.02, respectively). On the multivariate analysis, methylation of the ASPP1 gene promoter was an independent poor prognosis factor in ALL patients. Our results demonstrate that decreased expression of ASPP1 in patients with ALL is due to an abnormal methylation of its promoter and is associated with a poor prognosis.Oncogene ( Mutations of TP53 may result in an inhibition of protein function, which is associated with tumor progression and genetic instability (Caron de Fromentel and Soussi, 1992;Hollstein et al., 1994;Soussi et al., 1994). Although 40-50% of human tumors have mutations on TP53, the percentage of mutations in patients with leukemia is significantly lower (less that 10%), suggesting that other mechanisms may be involved in the inability of p53 to induce apoptosis since p53 does not suppress tumor growth or induce apoptosis in tumors with wild-type TP53.The recently described ASPP family of proteins comprised of ASPP1, ASPP2 and iASPP has been implicated in the apoptotic function of TP53 and p53 family members TP73L (p63) and TP73 (Bergamaschi et al., 2004). Different studies have shown that ASPP1 and ASPP2 increase the apoptotic effect of p53 by inducing the transcription of proapoptotic genes such as BAX and PIG3 mediated by TP53, while they have no influence on the transcription of MDM2 and CDKN1A (p21, Cip1), which mediate p53-dependent cell cycle arrest (Samuels-Lev et al., 2001;Slee and Lu, 2003;Bergamaschi et al., 2004). Transactivation of TP53-mediated transcription of proapoptotic genes mediated by ASPP1 and ASPP2 is completely abolished by increased expression of the evolutionary conserved TP53 inhibitor and third member of the ASPP family, iASPP (Bergamaschi et al., 2003).It has been hypothesized that in wild-type TP53 tumors, alterations of ASPP1 and/or ASPP2, can produce a selective advantage due to the lack of stimulation of apoptosis (Samuels-Lev et al., 2001;Slee and Lu, 2003;Bergamaschi et al., 2004). Samuels-Lev et al. (2001) These two authors contributed equally to this work.

Immune-mediated anti-tumoral responses, elicited by oncolytic viruses and augmented with checkpoint inhibition, may be an effective treatment approach for glioblastoma. Here in this multicenter phase 1/2 study we evaluated the combination of intratumoral delivery of oncolytic virus DNX-2401 followed by intravenous anti-PD-1 antibody pembrolizumab in recurrent glioblastoma, first in a dose-escalation and then in a dose-expansion phase, in 49 patients. The primary endpoints were overall safety and objective response rate. The primary safety endpoint was met, whereas the primary efficacy endpoint was not met. There were no dose-limiting toxicities, and full dose combined treatment was well tolerated. The objective response rate was 10.4% (90% confidence interval (CI) 4.2–20.7%), which was not statistically greater than the prespecified control rate of 5%. The secondary endpoint of overall survival at 12 months was 52.7% (95% CI 40.1–69.2%), which was statistically greater than the prespecified control rate of 20%. Median overall survival was 12.5 months (10.7–13.5 months). Objective responses led to longer survival (hazard ratio 0.20, 95% CI 0.05–0.87). A total of 56.2% (95% CI 41.1–70.5%) of patients had a clinical benefit defined as stable disease or better. Three patients completed treatment with durable responses and remain alive at 45, 48 and 60 months. Exploratory mutational, gene-expression and immunophenotypic analyses revealed that the balance between immune cell infiltration and expression of checkpoint inhibitors may potentially inform on response to treatment and mechanisms of resistance. Overall, the combination of intratumoral DNX-2401 followed by pembrolizumab was safe with notable survival benefit in select patients (ClinicalTrials.gov registration: NCT02798406).

Genetic variation in the catechol-O-methyltransferase (COMT) gene may influence the susceptibility to schizophrenia and the response to neuroleptic treatment. The authors tested for an association between a COMT haplotype and schizophrenia-spectrum disorders and for an eventual influence of a specific COMT genotype in the clinical outcome and in the response to treatment. The genotypes for single nucleotide polymorphisms rs737865, rs4633, rs6267, rs4680 (Val 158 Met) and rs165599 were determined in 207 patients with schizophrenia-spectrum disorders and 204 paired controls. Statistical tests for linkage disequilibrium and for case-control differences in haplotype frequencies were performed using log-linear modelling embedded within the expectation-maximization algorithm. P-values based on permutations were calculated using the software UNPHASED, and odds ratios were estimated using the SHEsis platform. The response to neuroleptic treatment was assessed by the Global Assessment of Functioning scale and the severity of psychotic symptoms by the positive and negative syndrome scale (PANSS) scale. The overall disease status was significantly associated with the T-G (Val) diplotype for rs4633-rs4680 (P ¼ 0.0049). A significant association was observed between schizophrenia, but not other related disorders, and genotypes GG (Val/Val) for rs4680 and TT for rs4633. Val/Val patients with schizophrenia showed a higher severity of the psychotic symptoms and a worse response to the neuroleptic treatment. COMT genetic variation seems to be involved in the psychotic symptomatology of the schizophreniaspectrum disorders and specifically in the narrow schizophrenia phenotype. Our results show an influence of the Val 158 Met polymorphism on the severity of psychotic symptoms and on the response to treatment.

ObjectiveTo determine the influence of the genotype and the level of expression of different enzymes involved in folate metabolism on the response to and toxicity of high-dose methotrexate treatment in pediatric osteosarcomas. Study designDHFR and Reduced folate carrier 1 (RFC1) semiquantitative expression was analyzed in 34 primary and metastatic osteosarcoma tissues by real-time polymerase chain reaction. The following polymorphisms were also analyzed in peripheral blood from 96 children with osteosarcoma and 110 control subjects: C677T, A1298C (MTHFR), G80A (RFC1), A2756G (MTR), C1420T (SHMT), the 28bp-repeat polymorphism, and 1494del6 of the TYMS gene. Treatment toxicity was scored after each cycle according to criteria from the World Health Organization. ResultsDHFR and RFC1 expression was lower in initial osteosarcoma biopsy specimens than in metastases (P = .024 and P = .041, respectively). RFC1 expression was moderately decreased in samples with poor histologic response to preoperative treatment (P = .053). Patients with osteosarcoma with G3/G4 hematologic toxicity were more frequently TT than CT/CC for C677T/MTHFR (P = .023) and GG for A2756G/MTR (P = .048 and P = .057 for gastrointestinal and hematologic toxicity, respectively). ConclusionsThe role of C677T/MTHFR and A2756G/MTR on chemotherapy-induced toxicity should be further investigated in pediatric osteosarcomas receiving high-dose methotrexate. Altered expression of DHFR and RFC1 is a feasible mechanism by which osteosarcoma cells become resistant to methotrexate.