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Esophageal squamous cell carcinoma is a major histological type of esophageal cancer, with distinct incidence and survival patterns among races. Although previous studies have characterized somatic mutations in this disease, a rigorous comparison between different patient populations has not been conducted. Here we sequence the samples of 316 Chinese patients, combine them with those from The Cancer Genome Atlas, and perform a comparative analysis between Asian and Caucasian patients. We find that mutated CSMD3 is associated with better prognosis in Asian patients. Applying a robust computational strategy that adjusts for both technical and biological confounding factors, we find that TP53, EP300, and NFE2L2 show higher mutational frequencies in Asian patients. Moreover, NFE2L2 mutations correlate with the allele status of a nearby high-Fst SNP, suggesting their potential interaction. Our study provides insights into the molecular basis underlying the striking racial disparities of this disease, and represents a general computational framework for such a cross-population comparison.

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Background Extracellular vesicles (EVs) are endogenous membrane vesicles with a diameter of 30–200 nm. It has been reported that hypoxic cancer cells can release numerous EVs to mediate multiple regional and systemic effects in the tumor microenvironment. Methods In this study, we used ultracentrifugation to extract EVs secreted by TE‐13, an esophageal squamous carcinoma (ESCC) cell line during normoxia and hypoxia and performed high‐throughput sequencing to detect exosomal miRNAs. Gene ontology (GO) and KEGG pathway analyses were used to reveal pathways potentially regulated by the miRNAs. Results A total of 10 810 miRNAs were detected; 50 were significantly upregulated and 34 were significantly downregulated under hypoxic environment. GO analysis identified enrichment of protein binding, regulation of transcription (DNA‐templated), and membrane as molecular function, biological process, and cellular component, respectively. KEGG pathway analysis revealed cancer‐associated pathways, phospholipase D signaling pathway, autophagy, focal adhesion and AGE‐RAGE signaling as the key pathways. Further verification experiment from qRT‐PCR indicated that miR‐128‐3p, miR‐140‐3p, miR‐340‐5p, miR‐452‐5p, miR‐769‐5p and miR‐1304‐p5 were significantly upregulated in EVs from hypoxia TE‐13 cells while miR‐340‐5p was significantly upregulated in two other ESCC cells, ECA109 and TE‐1. Conclusion This study, for the first time reveals changes in the expression of exosomal miRNAs in hypoxic ESCC cells and these findings will act as a resource to study the hypoxic tumor microenvironment and ESCC EVs.

Osimertinib, as a third‐generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), showed more potent efficacy against brain metastasis (BM) in untreated EGFR‐mutant nonsmall cell lung cancer (NSCLC) in the FLAURA study. However, the overall survival (OS) benefit of osimertinib and clinical value of cranial local therapy (CLT) in these patients remain undetermined. Here we conducted a retrospective study involving untreated EGFR‐mutant NSCLC patients with BMs receiving first‐line osimertinib or first‐generation EGFR‐TKIs. Upfront CLT was defined as CLT performed before disease progression to the first‐line EGFR‐TKIs. Pattern of treatment failure and survival outcomes were extensively investigated. Among the 367 patients enrolled, first‐generation EGFR‐TKI was administered in 265, osimertinib in 102 and upfront CLT performed in 140. Patients receiving osimertinib had more (P < .001) and larger BMs (P = .003) than those receiving first‐generation EGFR‐TKIs. After propensity score matching, osimertinib was found to prolong OS (37.7 vs 22.2 months, P = .027). Pattern of failure analyses found that 51.8% of the patients without upfront CLT developed their initial progressive disease (PD) in the brain and 59.0% of the cranial PD occurred at the original sites alone, suggesting potential clinical value of upfront CLT. Indeed, upfront stereotactic radiosurgery (SRS) and/or surgery was associated with improved OS among those receiving first‐generation EGFR‐TKIs (P = .019) and those receiving osimertinib (P = .041). In summary, compared to first‐generation EGFR‐TKIs, osimertinib is associated with improved OS in untreated EGFR‐mutant NSCLC with BMs. Meanwhile, upfront SRS and/or surgery may provide extra survival benefit, which needs to be verified in future studies.

Recent research indicates that the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway may play an important role in chronic inflammation which promotes cancer progression, yet the mechanism is not clear. The present study aimed to investigate the role of the JAK/STAT3 pathway in the growth and cancer-related inflammation (CRI) of esophageal squamous cell carcinoma (ESCC) by studying the crosstalk between the JAK/STAT3 pathway and nuclear factor-κB (NF-κB) and cyclooxygenase-2 (COX-2) which are important inflammatory factors associated with tumorigenesis. Cell growth and the cell cycle were assessed by CCK-8 assays and flow cytometry, respectively. The protein levels of STAT3, phosphorylated STAT3, VEGF, NF-κB p65, phosphorylated NF-κB p65 and COX-2 in ESCC cells following treatment with JAK2 inhibitor for 48 h or interleukin-6 (IL-6) for 24 h were detected. RT-PCR was performed to study the interaction among STAT3, NF-κB and COX-2 by transfection of siRNAs targeted at STAT3 and NF-κB. STAT3 was activated in 3 ESCC cell lines at different levels. Blocking the JAK/STAT3 pathway inhibited cancer growth through regulation of cell growth, cell cycle and angiogenesis. Likewise, abrogation of the JAK/STAT3 pathway decreased CRI by downregulating levels of NF-κB p65 phosphorylation, COX-2 and IL-6 concentration. In addition, CRI and cancer growth were accelerated by IL-6 through stimulation of the JAK/STAT3 and NF-κB p65 pathway. Moreover, STAT3 and NF-κB both regulated COX-2 as a downstream gene. The JAK/STAT3 pathway is an important pathway which links CRI and cancer growth through IL-6 and crosstalk with the NF-κB p65 subunit and COX-2. The STAT3 pathway could be a novel target both for cancer treatment and prevention in ESCC.

We have determined via segregation analyses from appropriate hybrids that two genes involved in protein synthesis, one encoding for a ribosomal protein (emtB) and one encoding for leucyl-tRNA synthetase (IeuS), cosegregate at a very high frequency and are linked in both Chinese hamster ovary and lung cells. In contrast, the emtA locus, defined by a second complementation group of emetine-resistant mutants which also have alterations affecting protein synthesis and probably the ribosome, is not linked to IeuS . In addition, we have determined that a third gene, one that can be altered to give rise to chromate resistance, is syntenic with emtB and IeuS . We have selected cell lines with mutations in each of these three linked genes and have shown that the three loci cosegregate at a high frequency. Because the mutations in these three linked genes provide easily distinguishable phenotypes, these cell lines should provide a powerful tool for examining several important questions concerning mitotic recombination in somatic cells.The genetic and biochemical dissection of protein synthesis in mammalian cells has benefited greatly in recent years from the use of mutant methodology. A large number of cultured somatic cell mutants have been isolated with alterations in different components of the protein synthetic machinery (9,10,12,16,18,19). One goal of this laboratory is to expand the number of such mutants in cultured Chinese hamster cells and to characterize them at the molecular level, especially mutants with alterations affecting various components of the ribosome . A second goal is to use such mutants to begin constructing a genetic map of this group of functionally related genes.We have isolated and partially characterized three distinct types of Chinese hamster cell mutants that were selected as being resistant to the protein synthesis inhibitor, emetine (19; J Hill, L. Vock, and J. Wasmuth, manuscript in preparation) . Although the phenotypes of all three types of mutants are very similar, and all have alterations affecting protein synthesis directly, they clearly define three distinct complementation groups . For all three classes, the emetine-resistant phenotypes are recessive. We have designated the loci defined by these different complementation groups as emtA, emtB, and emtC . Two laboratories (4, 8) have obtained evidence that Chinese hamster ovary (CHO), but not Chinese hamster lung (CHL), cells are functionally hemizygous for a locus that can be altered