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Background Long non‐coding RNA HOXC cluster antisense RNA 1 (HOXC‐AS1) is a novel lncRNA whose cancer‐promoting effect in gastric cancer and nasopharyngeal carcinoma has already been demonstrated. However, its functions in esophageal squamous cell carcinoma (ESCC) remains unknown. LncRNAs can interact with RNA‐binding proteins (RBPs) and affect gene expression levels through post‐transcriptional regulation. Insulin‐like growth factor 2 mRNA‐binding protein 2 (IGF2BP2) is a widely studied RBP, and sirtuin 1 also known as SIRT1 has been reported to be involved in cancer progression. Methods Establishment of in vivo models, HE and immunohistochemistry staining verified the oncogenic effect of HOXC‐AS1. The interaction relationship between HOXC‐AS1, IGF2BP2 and SIRT1 was verified by RNA pulldown and RNA immunoprecipitation (RIP) assay. Relative expression and stability changes of genes were detected by qPCR and actinomycin D experiments. Finally, the effect of HOXC‐AS1‐IGF2BP2‐SIRT1 axis on ESCC was verified by rescue experiments. Results HOXC‐AS1 is highly expressed in ESCC cells and plays oncogenic effects in vivo. qPCR showed the positive relationship between HOXC‐AS1 and SIRT1 following HOXC‐AS1 knockdown or overexpression. RNA‐pulldown, mass spectrometry and RIP assay demonstrated that IGF2BP2 is an RBP downstream of HOXC‐AS1. Then, RIP and qPCR showed that IGF2BP2 could bind to SIRT1 mRNA and knockdown IGF2BP2 resulted in decreased SIRT1 mRNA level. Finally, a series of rescue assay showed that the HOXC‐AS1‐IGF2BP2‐SIRT1 axis can affect the function of ESCC. Conclusion LncRNA HOXC‐AS1 acts as an oncogenic role in ESCC, which impacts ESCC progression by interaction with IGF2BP2 to stabilize SIRT1 expression.

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Ferroptosis is an emerging form of non-apoptotic regulated cell death which is different from cell death mechanisms such as autophagy, apoptosis and necrosis. It is characterized by iron-dependent lipid peroxide accumulation. Circular RNA (circRNA) is a newly studied evolutionarily conserved type of non-coding RNA with a covalent closed-loop structure. It exhibits universality, conservatism, stability and particularity. At present, the functions that have been studied and found include microRNA sponge, protein scaffold, transcription regulation, translation and production of peptides, etc. CircRNA can be used as a biomarker of tumors and is a hotspot in RNA biology research. Studies have shown that ferroptosis can participate in tumor regulation through the circRNA molecular pathway and then affect cancer progression, which may become a direction of cancer diagnosis and treatment in the future. This paper reviews the molecular biological mechanism of ferroptosis and the role of circular RNA in tumors and summarizes the circRNA related to ferroptosis in tumors, which may inspire research prospects for the precise prevention and treatment of cancer in the future.

Rationale: Central neurocytoma occurring outside the ventricles is known as extraventricular neurocytoma (EVN). EVN is rare and its magnetic resonance imaging (MRI) findings vary greatly and overlap with the imaging features of other intracerebral primary tumors. Patient concerns: A 21-year-old woman with an intrauterine pregnancy of 18+2 weeks complained of dizziness and headache for 3 months. Diagnosis: A 8.6 cm × 5.8 cm × 3.7 cm space-occupying lesion was seen in the right frontal lobe on MRI, with mixed long signals on T1-weighted imaging and mixed slightly long signals on T2-weighted imaging, slightly hyperintense on T2-weighted imaging fluid attenuated inversion recovery images, and a large-scope long T1-weighted imaging and long T2-weighted imaging cystic component at the center of the lesion. A thick fence-like enhancement of the solid component at the periphery of the lesion was observed after injecting a contrast medium, while the internal cystic component was not enhanced. The MRI diagnosis was of glioma. The lesion was pathologically confirmed as an atypical central neurocytoma of the right frontal lobe. Interventions: Resection of the lesion and postoperative radiotherapy. Outcomes: The patient was lost to follow-up. Lessons: EVN can be considered as a differential diagnosis for lesions occurring in the cerebral hemispheres of young patients with cystic degeneration, thick fence-like enhancement, and peritumoral edema on MRI.