Around 10%–20% of all cancer deaths worldwide are caused by lung cancer (Zhao et al., 2021). It accounts for about 1.82 million new cases each year, resulting in 1.6 million deaths (Ferlay et al., 2015). According to pathological classification, lung cancer can be divided into two main types: small cell lung cancer (SCLC), which comprises 15% of cases (Faivre et al., 2017), and non-small cell lung cancer (NSCLC), which accounts for 85% of cases (Molina et al., 2008, Zhao et al., 2019). In NSCLC, three subtypes are recognized: large cell lung carcinoma (LCLC; 10%), lung squamous cell carcinoma (LUSC; 25%), and lung adenocarcinoma (LUAD; 40%) (Chen et al., 2017; C. Zhang et al., 2020). While the survival rates for many types of cancer have improved due to advancements in diagnosis and treatment, lung cancer continues to have a low 5-year survival rate of only 17.7% (Ettinger et al., 2017). Early-stage lung cancer has a considerably higher survival rate compared to advanced-stage lung cancer. Therefore, it is crucial to identify diagnostic biomarkers and therapeutic targets for lung cancer tumorigenesis and gain a deeper understanding of the underlying molecular mechanisms involved.

Currently, there are four primary treatment options for lung cancer: surgery, chemotherapy, radiation, immunotherapy and targeted therapy (Zhang et al., 2023). Various treatment options are available based on factors such as the grade and stage of the cancer (Lemjabbar-Alaoui et al., 2015, Rajabi et al., 2023). Despite advancements in tumor diagnosis and treatment over the past 25 years, the efficacy of chemotherapy is limited, leading to low survival rates (Fazilat‐Panah et al., 2021, Rama Ballesteros et al., 2020, Sun et al., 2019). Due to this problem, people are constantly searching for new diagnostic and treatment methods. Hence, cancer research is focused on comprehensive institutional studies and the exploration of novel therapeutic targets (Pan et al., 2022, Sedighi Pashaki et al., 2023). In recent decades, researchers have studied the relationship between protein-coding genes and lung cancer. While only 2% of the human genome encodes protein, 85% is transcribed into non-coding RNAs, a new family of RNAs that is poorly understood, such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) (Fatica and Bozzoni, 2014, Skroblin and Mayr, 2014).

Over the past decade, there has been a rapid accumulation of research on the functions of circRNAs. circRNAs are a type of single-stranded circular RNA that was initially discovered in plants and later found in human cells (Memczak et al., 2013). Interestingly, in certain cases, the abundance of circRNAs can exceed that of linear mRNA by more than tenfold (Jeck et al., 2013, Sun et al., 2023). In contrast to linear RNAs, circRNAs lack free ends, a 5′ cap, and a 3′ poly(A) tail; instead, their ends are connected through phosphodiester bonds, forming a circular structure (Zhang et al., 2014). circRNAs play diverse roles in cellular processes. They can regulate gene transcription and translation through interactions with miRNAs, proteins, and even direct translation (S. Qu et al., 2018). This involvement in gene regulation occurs within a complex network known as the circRNA/miRNA/mRNA competitive endogenous RNA (ceRNA) axis network. As a function of this ceRNA axis network, miRNAs can bind to both circRNAs and mRNAs, thereby influencing the expression of target genes (Luo et al., 2020). Studies have shown that dysregulation of circRNAs in ceRNA axis network correlated with tumor cell proliferation, apoptosis, invasion, and migration. Furthermore, the expression of circRNAs varies among different tumor cells, suggesting their potential as diagnostic and prognostic markers (Li et al., 2017, Schwarz and Horestani, 2025). In this review, we aim to explore the latest research on the role of circRNAs in the pathogenesis of lung cancer. Specifically, we will focus on investigating how circRNAs, miRNAs, and mRNAs interact to form a complex regulatory network. By gaining a deeper understanding of this regulatory network, we can develop and apply novel ideas and strategies for early diagnosis and improved treatment approaches in lung cancer.