Blood-based biomarker detection offers the benefit of being a noninvasive method and can be used as a supplementary way of low-dose computed tomography (LDCT) for early screening of lung cancer. Different histological subtypes are regularly classified using different molecular markers; for SCLC, neuron-specific enolase (NSE) and progestin-releasing peptide (ProGRP) are often used as tumor markers; for NSCLC, carcinoembryonic antigen (CEA), squamous cancer cell antigen (SCCA), and cytokeratin 19-fragments (CYFRA 21-1) are routinely used as tumor markers (Holdenrieder, 2016).Histological analysis, though, lacks great specificity and is intrinsically objective. To demonstrate, certain tumor markers, like CEA, can be raised not just in non-carcinogenic illnesses or benign tumors but also in lung cancer (X. Li et al., 2013). To diagnose lung cancer in its early stages, it is important to find new, more sensitive, and specific biomarkers. LncRNAs have been shown in many studies to be new and useful molecular markers for the diagnosis of lung cancer. Certain lncRNAs, such MALAT1, are not extremely sensitive in the identification of lung cancer, similar to other blood-based tumor indicators. This is due to the diverse expression levels of MALAT1 in many cancer types (Chu et al., 2017). In order to categorize lung cancer, CHIP helps in determining the levels of agreed diagnostic lncRNAs biomarkers, such as XLOC_009167. The understanding and specificity of lncRNA XLOC_009167 are higher in main lung cancer tissues and cell lines related to para-carcinoma tissues and cell lines, and it is considerably up-regulated in contrast to other conventional markers that are frequently applied in clinical practice (CYFR21-1 and NSE). Also, investigation establish that LncRNA XLOC_009167 can distinguish between lung cancer patients and healthy persons as well as between pneumonia and early-stage lung cancer (Jiang et al., 2018).
In non-small cell lung cancer, C6orf176-TV1 or C6orf176-TV2 levels is down-regulated and associated with the mark of differentiation. For patients with NSCLC, it might assist as a diagnostic indicator (J. Wang et al., 2016). GAS5, a long noncoding RNA, shows decreased levels in plasma of NSCLC patients related to healthy controls. Its expression increase post-surgery. GAS5’s diagnostic sensitivity (82.2%) and specificity (72.7%) in individual NSCLC from controls propose its potential as a valuable biomarker in plasma-based diagnostics(Liang et al., 2016).study found that circulating lncRNAs, GAS5 and SOX2OT, are possible biomarkers for NSCLC diagnosis. GAS5 was expressively downregulated, while SOX2OT was upregulated in NSCLC patients. Their levels exactly illustrious NSCLC patients from normal. The combination of GAS5 and SOX2OT better diagnostic sensitivity and specificity. These results propose that a diagnostic panel including both lncRNAs could enhance NSCLC diagnosis and prognosis assessment (Kamel et al., 2019). LncRNA ZFAS1 is upregulated in NSCLC and stimulates tumor progression. Knockdown of ZFAS1 reduced NSCLC cell multiplying and invasion, increased apoptosis, and decrease tumor growth in mice. Additionally, ZFAS1 inversely affected miR-150-5p and positively affected HMGA2 expression. miR-150-5p inhibition or HMGA2 increase level reversed ZFAS1 knockdown effects. Thus, ZFAS1 promotes NSCLC development through the miR-150-5p/HMGA2 pathway(Zeng et al., 2020) lncRNAs linc00312 and linc00673 are possible biomarkers for NSCLC. Levels of linc00312 was considerably decreased, and linc00673 was increased in NSCLC tissues. Low linc00312 levels associated with advanced Tumor-Node-Metastasis stage, while high linc00673 levels associated to specific histological types. These findings suggest their potential roles in early NSCLC diagnosis and treatment(Tan et al., 2017).The study estimated MALAT1 as a blood-based marker for lung cancer. MALAT1 was lower in lung cancer patients’ blood compared to normal but higher in metastatic cases. Blood by bone or brain metastasis showed higher MALAT1 than lymph node or pleura tumors. These results propose MALAT1 can help screen lung cancer and indicate metastasis, reflecting a host response to the disease(Guo et al., 2015).The study identified key biomarkers for lung adenocarcinoma (LUAD) using GEO datasets. They also found forty one differentially expressed lncRNAs and eight hundred five mRNAs. A ceRNA system strained lncRNAs CLDN10-AS1, SFTA1P, SRGAP3-AS2, and ADAMTS9-AS2, and highest mRNAs counted in DLGAP5, MCM7, RACGAP1, and RRM2. Immunohistochemistry long-established their upregulation in LUAD. CLDN10-AS1, SFTA1P, and ADAMTS9-AS2 remained associated with diagnosis, suggesting their potential as LUAD biomarkers(Jin et al., 2020). Early selection and diagnosis obviously progress survival outcomes for malignant tumor patients. Study indicates important upregulation or downregulation of many lncRNAs in tumor part compared to normal tissues, stress their diagnostic potential. Novel lncRNAs are vital for early detection and prognosis improvement. Relating lncRNAs with miRNAs and additional tumor biomarkers improves diagnostic accurateness. Though, more whole studies are important to fully understand the diagnostic place of lncRNAs in cancer. Irrespective of existing challenges, lncRNAs play vital roles in tumor development and hold promise for clinical applications.
