Targeted Molecular Profiling of Circulating Cell-Free DNA in Patients With Advanced Hepatocellular Carcinoma.

PURPOSE: Next-generation sequencing (NGS) of tumor-derived, circulating cell-free DNA (cfDNA) may aid in diagnosis, prognostication, and treatment of patients with hepatocellular carcinoma (HCC). The operating characteristics of cfDNA mutational profiling must be determined before routine clinical implementation. METHODS: This was a single-center, retrospective study with the primary objective of defining genomic alterations in circulating cfDNA along with plasma-tissue genotype agreement between NGS of matched tumor samples in patients with advanced HCC. cfDNA was analyzed using a clinically validated 129-gene NGS assay; matched tissue-based NGS was analyzed with a US Food and Drug Administration-authorized NGS tumor assay. RESULTS: Fifty-three plasma samples from 51 patients with histologically confirmed HCC underwent NGS-based cfDNA analysis. Genomic alterations were detected in 92.2% of patients, with the most commonly mutated genes including TERT promoter (57%), TP53 (47%), CTNNB1 (37%), ARID1A (18%), and TSC2 (14%). In total, 37 (73%) patients underwent paired tumor NGS, and concordance was high for mutations observed in patient-matched plasma samples: TERT (83%), TP53 (94%), CTNNB1 (92%), ARID1A (100%), and TSC2 (71%). In 10 (27%) of 37 tumor-plasma samples, alterations were detected by cfDNA analysis that were not detected in the patient-matched tumors. Potentially actionable mutations were identified in 37% of all cases including oncogenic/likely oncogenic alterations in TSC1/2 (18%), BRCA1/2 (8%), and PIK3CA (8%). Higher average variant allele fraction was associated with elevated alpha-fetoprotein, increased tumor volume, and no previous systemic therapy, but did not correlate with overall survival in treatment-naïve patients. CONCLUSION: Tumor mutation profiling of cfDNA in HCC represents an alternative to tissue-based genomic profiling, given the high degree of tumor-plasma NGS concordance; however, genotyping of both blood and tumor may be required to detect all clinically actionable genomic alterations.

A Knock-In Mouse Model of Thymoma With the GTF2I L424H Mutation.

INTRODUCTION: The pathogenesis of thymic epithelial tumors remains largely unknown. We previously identified GTF2I L424H as the most frequently recurrent mutation in thymic epithelial tumors. Nevertheless, the precise role of this mutation in tumorigenesis of thymic epithelial cells is unclear. METHODS: To investigate the role of GTF2I L424H mutation in thymic epithelial cells in vivo, we generated and characterized a mouse model in which the Gtf2i L424H mutation was conditionally knocked-in in the Foxn1+ thymic epithelial cells. Digital spatial profiling was performed on thymomas and normal thymic tissues with GeoMx-mouse whole transcriptome atlas. Immunohistochemistry staining was performed using both mouse tissues and human thymic epithelial tumors. RESULTS: We observed that the Gtf2i mutation impairs development of the thymic medulla and maturation of medullary thymic epithelial cells in young mice and causes tumor formation in the thymus of aged mice. Cell cycle-related pathways, such as E2F targets and MYC targets, are enriched in the tumor epithelial cells. Results of gene set variation assay analysis revealed that gene signatures of cortical thymic epithelial cells and thymic epithelial progenitor cells are also enriched in the thymomas of the knock-in mice, which mirrors the human counterparts in The Cancer Genome Atlas database. Immunohistochemistry results revealed similar expression pattern of epithelial cell markers between mouse and human thymomas. CONCLUSIONS: We have developed and characterized a novel thymoma mouse model. This study improves knowledge of the molecular drivers in thymic epithelial cells and provides a tool for further study of the biology of thymic epithelial tumors and for development of novel therapies.

The epidemiology of desmoid tumors in Denmark.

INTRODUCTION/AIM: The epidemiology, demographic, clinical, treatment, and healthcare resource utilization (HRU) characteristics of desmoid tumor (DT) patients treated at two sarcoma centers in Denmark is described. METHODS: Using Danish health registers, we studied DT patients treated at two sarcoma centers between 2009 and 2018. For each patient, ten persons from the general population were randomly matched on birth year, sex, and region of residence. RESULTS: Of the 179 DT patients identified, 76% were female and the median patient age was 38 years at diagnosis (interquartile range: 31-50). An average annual incidence of DTs over the study period was 3.2 per 1000,000 individuals with the observed annual incidence of DTs ranging from 2.2 (2011) to 4.3 (2017) per 1000,000 individuals. No notable linear time trend in incidence was observed. Anatomical DT sites included extra-abdominal (49%), abdominal wall (40%), and intra-abdominal or retroperitoneal areas (8%). In total, 56% of patients were initially treated surgically. However, while 75% of patients diagnosed with DT between 2009 and 2014 were initially treated surgically, this was true for only 32% of patients diagnosed with DT between 2015 and 2018. A total of 56% of DT patients used chemotherapeutic agents, tyrosine kinase inhibitors, NSAIDs, opioids, antidepressants, or steroids at some point during the three years before their DT diagnoses. In contrast, 70% of surgically treated and 63% of non-surgically treated patients used one of these drugs in the subsequent three years, including NSAIDs (45% surgical vs. 33% non-surgical), opioids (39% surgical vs. 27% non-surgical), and steroids (22% surgical vs. 18% non-surgical). The average number of inpatient and outpatient visits, days of hospitalization, and additional surgical procedures were higher among DT patients than the comparison cohort. CONCLUSION: DTs are rare but have a large impact on patients' health, HRU, and medication utilization.

Diet-regulated production of PDGFcc by macrophages controls energy storage.

The mechanisms by which macrophages regulate energy storage remain poorly understood. We identify in a genetic screen a platelet-derived growth factor (PDGF)/vascular endothelial growth factor (VEGF)-family ortholog, Pvf3, that is produced by macrophages and is required for lipid storage in fat-body cells of Drosophila larvae. Genetic and pharmacological experiments indicate that the mouse Pvf3 ortholog PDGFcc, produced by adipose tissue-resident macrophages, controls lipid storage in adipocytes in a leptin receptor- and C-C chemokine receptor type 2-independent manner. PDGFcc production is regulated by diet and acts in a paracrine manner to control lipid storage in adipose tissues of newborn and adult mice. At the organismal level upon PDGFcc blockade, excess lipids are redirected toward thermogenesis in brown fat. These data identify a macrophage-dependent mechanism, conducive to the design of pharmacological interventions, that controls energy storage in metazoans.