Diagnostic value of lncRNA LINC00900 in papillary thyroid carcinoma metastasis and its oncogenic role through sponging miR-545-3p

Abstract Objectives Papillary Thyroid carcinoma (PTC) is a common endocrine malignancy, often with lymph node metastasis. This study aims to investigate the regulatory mechanism between LINC00900 and miR-545-3p in TC with lymph node metastasis, thereby providing novel insights for the diagnosis and therapeutic intervention of this disease. Methods A study involving 218 patients divided into low (n=106) and high (n=112) LINC00900 expression groups, utilized qPCR to analyze the levels of LINC00900 and miR-545-3p. Pearson correlation, chi-square test and ROC curve analysis were performed to estimate clinical associations and diagnostic value. Binding sites were predicted and confirmed via dual-luciferase assays. Functional tests (CCK-8, transwell) assessed cell proliferation, migration, and invasion. Results In PTC, elevated LINC00900 expression shows significant correlations with aggressive pathological features, including larger tumor size, advanced TNM stage, microcalcifications, and abnormal lymph node ultrasound findings. Patients with TC and lymph node metastasis exhibit higher blood and tissue levels of LINC00900 compared to those with benign nodules and adjacent tissue, respectively. A negative correlation exists between LINC00900 and miR-545-3p in tumor tissues, and ROC curve analysis confirms LINC00900’s diagnostic potential. Mechanistically, dual-luciferase reporter assays demonstrate that LINC00900 directly binds to miR-545-3p. Functional studies reveal that LINC00900 knockdown upregulates miR-545-3p and significantly suppresses tumor cell proliferation, migration, and invasion, while the miR-545-3p inhibitor reverses these effects. Conclusions LINC00900 is a potential diagnostic biomarker for PTC with lymph node metastasis and promotes tumor progression by interacting with miR-545-3p, offering both diagnostic and therapeutic value.