Liquid biopsy in non-small cell lung cancer: current status and future outlook—a narrative review

Lung cancer ranks first as the cause of cancer-associated deaths gobally. The American Cancer Society estimates for 228,820 new cases and 135,720 deaths from lung cancer in the United States for the year 2020. Targeted treatment options have rapidly emerged for non-small cell lung cancer (NSCLC) within the past decade. Screening for molecular aberrations is mainly done by tissue biopsy. However, in some cases a biopsy is not possible, or patients do not consent to it. Hence, liquid biopsy remains the only option. Relevant data about the topic of liquid biopsy, with a special focus on NSCLC, was obtained via a PubMed search. We included mainly literature published from 2010 onwards, omitting older studies whenever possible. With this review of the literature, we give an overview of different liquid biopsy approaches, as well as their respective advantages and disadvantages. We have reviewed the assessment of epidermal growth factor receptor (EGFR) mutation status in particular, and go into detail with current use of liquid biopsy in everyday clinical practice. Today, liquid biopsy is still infrequently used, depending on the treatment center, but popularity is steadily increasing. Various different approaches are already available, but costs and level of sensitivity significantly differ between techniques. By using liquid biopsy more widely in selected patients, complication rates can be reduced, and constant disease monitoring is made considerably easier

E2F transcription factor-1 modulates expression of glutamine metabolic genes in mouse embryonic fibroblasts and uterine sarcoma cells

Metabolic reprogramming is considered as a hallmark of cancer and is clinically exploited as a novel target for therapy. The E2F transcription factor-1 (E2F1) regulates various cellular processes, including proliferative and metabolic pathways, and acts, depending on the cellular and molecular context, as an oncogene or tumor suppressor. The latter is evident by the observation that E2f1-knockout mice develop spontaneous tumors, including uterine sarcomas. This dual role warrants a detailed investigation of how E2F1 loss impacts metabolic pathways related to cancer progression. Our data indicate that E2F1 binds to the promoter of several glutamine metabolism-related genes. Interestingly, the expression of genes in the glutamine metabolic pathway were increased in mouse embryonic fibroblasts (MEFs) lacking E2F1. In addition, we confirm that E2f1 <sup>-/-</sup> MEFs are more efficient in metabolizing glutamine and producing glutamine-derived precursors for proliferation. Mechanistically, we observe a co-occupancy of E2F1 and MYC on glutamine metabolic promoters, increased MYC binding after E2F1 depletion and that silencing of MYC decreased the expression of glutamine-related genes in E2f1 <sup>-/-</sup> MEFs. Analyses of transcriptomic profiles in 29 different human cancers identified uterine sarcoma that showed a negative correlation between E2F1 and glutamine metabolic genes. CRISPR/Cas9 knockout of E2F1 in the uterine sarcoma cell line SK-UT-1 confirmed elevated glutamine metabolic gene expression, increased proliferation and increased MYC binding to glutamine-related promoters upon E2F1 loss. Together, our data suggest a crucial role of E2F1 in energy metabolism and metabolic adaptation in uterine sarcoma cells

Non-invasive in vivo tracking of fibrin degradation by fluorescence imaging

Fibrin-based sealants consist of natural coagulation factors involved in the final phase of blood coagulation, during which fibrinogen is enzymatically converted by thrombin to form a solid-phase fibrin clot. For applications in tissue regeneration, a controlled process of matrix degradation within a certain period of time is essential for optimal wound healing. Hence, it is desirable to follow the kinetics of fibrinolysis at the application site. Non-invasive molecular imaging systems enable real-time tracking of processes in the living animal. In this study, a non-invasive fluorescence based imaging system was applied to follow and quantify site-specific degradation of fibrin sealant. To enable non-invasive tracking of fibrin in vivo, fibrin-matrix was labelled by incorporation of a fluorophore-conjugated fibrinogen component. Protein degradation and release of fluorescence were, in a first step, correlated in vitro. In vivo, fluorophore-labelled fibrin was subcutaneously implanted in mice and followed throughout the experiment using a multispectral imaging system. For the fluorescent fibrin, degradation correlated with the release of fluorescence from the clots in vitro. In vivo it was possible to follow and quantify implanted fibrin clots throughout the experiment, demonstrating degradation kinetics of approximately 16 days in the subcutaneous compartment, which was further confirmed by histological evaluation of the application site

Prediction of Postoperative Clinical Outcomes in Resected Stage I Non-Small Cell Lung Cancer Focusing on the Preoperative Glasgow Prognostic Score

Background: The Glasgow Prognostic Score (GPS), which consists of albumin and C-reactive protein (CRP), may predict overall survival (OS) in cancer patients. The aim of this retrospective analysis was to evaluate the clinical impact of the preoperative GPS on patients with resected early stage non-small cell lung cancer (NSCLC). Methods: 300 patients with curatively resected stage I NSCLC were followed-up for OS, recurrence-free survival (RFS), cancer-specific survival (CSS), and death from other causes. Results: 229 patients (76%) had a preoperative GPS of 0, and 71 (24%) a GPS ≥ 1. The three-year probabilities of RFS, OS, CSS, and death from other causes were 81%, 84%, 88%, and 96% in patients with GPS = 0, and 79%, 74%, 91%, and 82% in patients with a GPS ≥ 1, respectively. GPS ≥ 1 was significantly associated with a higher risk of death from other causes (p = 0.022), serving as an independent predictor of death from other causes (p = 0.034). Pathologically elevated CRP levels (CRP > 5 mg/L) were found in 91 patients (30%). The mean CRP level was 7.88 ± 15.80 mg/L (0.5–135.6 mg/L). Pre-treatment CRP level was significantly associated with coronary heart disease (p < 0.0001), histology (p = 0.013), tumor size (p = 0.018), tumor stage (p = 0.002), and vascular invasion (p = 0.017). Conclusion: The preoperative GPS predicts adverse survival outcomes in patients with resected stage I NSCLC