Use of Neoadjuvant Vandetanib in Aggressive Pediatric Medullary Thyroid Carcinoma

Novel use of vandetanib in a child with aggressive MTC with prolonged response to treatment.

Case Report: Castleman Disease With an Associated Stromal Spindle Cell Proliferation, PDGFRB Mutation and p53 Expression: Clonal Origins of a Rare Disease

Castleman disease (CD) is a rare lymphoproliferative disorder with distinct clinical subtypes. However, our understanding of the underlying pathogenesis of particular subtypes of CD remains unclear. While the characteristic morphologic changes within UCD, including occasional cases of overgrowth of spindled stromal and follicular dendritic cells have been described, the nature and origin of these spindle cells remain elusive. Few reports have suggested that underlying stromal cells in UCD are clonally neoplastic and may be of fibroblastic reticular cell (FRC) or follicular dendritic cell (FDC) origins given their close clonal relationship. Although certain histomorphologic features may aid diagnosis, there are no specific biomarkers that can differentiate a reactive process mimicking UCD from true UCD. Hence, we describe an index case with morphology consistent with the hyaline vascular subtype of UCD with concomitant atypical smooth muscle actin (SMA)-positive stromal spindle cell proliferation containing a recurrent PDGFRB N666S mutation and upregulation of p53 expression. Further analysis of 21 additional cases of UCD identified increased p53 expression by digital image analysis and SMA positive stromal cells predominantly within the paracortical and intrafollicular areas further strengthening the hypothesis of the stromal cellular derivation and origins of UCD.

Treatment at Specialized Cancer Centers Is Associated with Improved Survival in Adolescent and Young Adults with Soft Tissue Sarcoma

Background: Soft tissue sarcomas (STS) are a heterogeneous group of tumors whose management benefits from a multidisciplinary therapeutic approach. Published data suggest that cancer treatment at a specialized cancer center (SCC) can improve survival in other cancers. Therefore, we examined the impact of the location of treatment on survival in children and adolescents and young adults (AYAs) with STS. Methods: We performed a population-based analysis of children and AYAs hospitalized within 1 year of diagnosis with first primary STS (2000-2014) using the California Cancer Registry linked with hospitalization data. Patients were categorized based on receiving all inpatient treatments at a SCC versus part/none. Multivariable Cox proportional hazards regression identified factors associated with overall and STS-specific survival by age group. Results are presented as adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Results: Of the 1,674 patients with STS, 142 were children (0-14) and 1,532 were AYAs (15-39) and 89.4% and 40.4% received all inpatient treatments at a SCC, respectively. Overall, the 5-year survival was improved for patients who received all inpatient care at a SCC (59.8% vs. those who received part/none, 50.7%). Multivariable regression analysis found that having all treatments at a SCC was associated with better overall survival (HR, 0.79, CI: 0.65-0.95) in AYAs, but not in children. Conclusions: Our findings demonstrate that treatment for STS at a SCC is associated with better survival in AYAs. Eliminating barriers to treatment of AYAs with STS at SCCs could improve survival in this population.

Venous malformations

Venous malformations include a spectrum of slow-flow malformations that together are the most common forms of vascular anomalies. Care of these patients requires a multi-disciplinary approach. Goals of care are to ameliorate symptoms and to preserve function. Use of therapeutic compression garments remains the mainstay of therapy. There are new and promising therapies over the last few years that will be invaluable tools for optimal care of this complex patient population. Advances in medical therapy through inhibition of the mTOR/PI3K/AKT pathway with Sirolimus and more proximal targeted drugs along with advances in sclerotherapy techniques are promising for the long-term improvement and amelioration of symptoms in patients with venous malformations.

Therapeutic strategies for diffuse midline glioma from high-throughput combination drug screening

Diffuse midline gliomas (DMGs) are universally lethal malignancies occurring chiefly during childhood and involving midline structures of the central nervous system, including thalamus, pons, and spinal cord. These molecularly related cancers are characterized by high prevalence of the histone H3K27M mutation. In search of effective therapeutic options, we examined multiple DMG cultures in sequential quantitative high-throughput screens (HTS) of 2706 approved and investigational drugs. This effort generated 19,936 single-agent dose responses that inspired a series of HTS-enabled drug combination assessments encompassing 9195 drug-drug examinations. Top combinations were validated across patient-derived cell cultures representing the major DMG genotypes. In vivo testing in patient-derived xenograft models validated the combination of the multi-histone deacetylase (HDAC) inhibitor panobinostat and the proteasome inhibitor marizomib as a promising therapeutic approach. Transcriptional and metabolomic surveys revealed substantial alterations to key metabolic processes and the cellular unfolded protein response after treatment with panobinostat and marizomib. Mitigation of drug-induced cytotoxicity and basal mitochondrial respiration with exogenous application of nicotinamide mononucleotide (NMN) or exacerbation of these phenotypes when blocking nicotinamide adenine dinucleotide (NAD⁺) production via nicotinamide phosphoribosyltransferase (NAMPT) inhibition demonstrated that metabolic catastrophe drives the combination-induced cytotoxicity. This study provides a comprehensive single-agent and combinatorial drug screen for DMG and identifies concomitant HDAC and proteasome inhibition as a promising therapeutic strategy that underscores underrecognized metabolic vulnerabilities in DMG.

Sex differences in β-amyloid accumulation in 3xTg-AD mice: role of neonatal sex steroid hormone exposure

The risk of Alzheimer's disease (AD) is higher in women than in men, a sex difference that likely results from the effects of sex steroid hormones. To investigate this relationship, we first compared progression of β-amyloid (Aβ) pathology in male and female triple transgenic (3xTg-AD) mice. We found that female 3xTg-AD mice exhibit significantly greater Aβ burden and larger behavioral deficits than age-matched males. Next, we evaluated how the organizational effects of sex steroid hormones during postnatal development may affect adult vulnerability to Aβ pathology. We observed that male 3xTg-AD mice demasculinized during early development exhibit significantly increased Aβ accumulation in adulthood. In contrast, female mice defeminized during early development exhibit a more male-like pattern of Aβ pathology in adulthood. Taken together, these results demonstrate significant sex differences in pathology in 3xTg-AD mice and suggest that these differences may be mediated by organizational actions of sex steroid hormones during development.

Two closely linked genes encoding thioredoxin and thioredoxin reductase in Clostridium litorale

The genes encoding thioredoxin and thioredoxin reductase of Clostridium litorale were cloned and sequenced. The thioredoxin reductase gene (trxB) encoded a protein of 33.9 kDa, and the deduced amino acid sequence showed 44% identity to the corresponding protein from Escherichia coli. The gene encoding thioredoxin (trxA) was located immediately downstream of trxB. TrxA and TrxB were each encoded by two gene copies, both copies presumably located on the chromosome. Like other thioredoxins from anaerobic, amino-acid-degrading bacteria investigated to date by N-terminal amino acid sequencing, thioredoxin from C. litorale exhibited characteristic deviations from the consensus sequence, e.g., GCVPC instead of WCGPC at the redox-active center. Using heterologous enzyme assays, neither thioredoxin nor thioredoxin reductase were interchangeable with the corresponding proteins of the thioredoxin system from E. coli. To elucidate the molecular basis of that incompatibility, Gly-31 in C. litorale thioredoxin was substituted with Trp (the W in the consensus sequence) by site-directed mutagenesis. The mutant protein was expressed in E. coli and was purified to homogeneity. Enzyme assays using the G31W thioredoxin revealed that Gly-31 was not responsible for the observed incompatibility with the E. coli thioredoxin reductase, but it was essential for activity of the thioredoxin system in C. litorale.

Glycine reductase of Clostridium litorale. Cloning, sequencing, and molecular analysis of the grdAB operon that contains two in-frame TGA codons for selenium incorporation

A 2.8-kb HindIII fragment, containing three open reading frames, has been cloned and sequenced from Clostridium litorale. The first gene grdA encoded the selenocysteine-containing protein PA of the glycine reductase complex, a protein of 159 amino acids with a deduced molecular mass of 16.7 kDa. The second gene (grdB) encoded the 47-kDa subunit of the substrate-specific selenoprotein PB glycine that is composed of 437 amino acids. The third gene contained the 5'-region of the gene for thioredoxin reductase, trxB. All gene products shared high similarity with the corresponding proteins from Eubacterium acidaminophilum. In both genes grdA and grdB, the opal termination codon (TGA) was found inframe, indicating the presence of selenocysteine in both polypeptides. Northern-blot analysis showed that grdA and grdB are organized as one operon. Unlike Escherichia coli, no stable secondary structures of the corresponding mRNA were found immediately downstream of the UGA codons to direct an insertion of selenocysteine into the grdA and grdB transcripts of C. litorale. Instead, a secondary structure was identified in the 3'-untranslated region of grdB.