Thyroid cancer is a common endocrine malignancy with a rapidly increasing global incidence. The molecular pathogenesis of thyroid cancer involves genetic and epigenetic alterations in signaling pathways, such as the MAPK and PI3K-AKT pathways. These alterations, including mutations, gene copy-number gains, and aberrant gene methylation, are key drivers of tumor growth and progression. The BRAF-V600E mutation, RAS mutations, and RET-PTC translocation are among the most prevalent genetic alterations. The PI3K-AKT pathway is particularly important in differentiated thyroid cancers, while the MAPK pathway is crucial for papillary thyroid cancer. The accumulation of multiple genetic alterations and their synergistic cooperation drive the progression of thyroid cancer. Impairment of the iodide-handling machinery, which is essential for thyroid hormone synthesis, is also a significant factor in advanced thyroid cancers. Recent advances in molecular understanding have led to the development of novel diagnostic and therapeutic strategies, including the use of genetic markers and targeted therapies.Thyroid cancer is a common endocrine malignancy with a rapidly increasing global incidence. The molecular pathogenesis of thyroid cancer involves genetic and epigenetic alterations in signaling pathways, such as the MAPK and PI3K-AKT pathways. These alterations, including mutations, gene copy-number gains, and aberrant gene methylation, are key drivers of tumor growth and progression. The BRAF-V600E mutation, RAS mutations, and RET-PTC translocation are among the most prevalent genetic alterations. The PI3K-AKT pathway is particularly important in differentiated thyroid cancers, while the MAPK pathway is crucial for papillary thyroid cancer. The accumulation of multiple genetic alterations and their synergistic cooperation drive the progression of thyroid cancer. Impairment of the iodide-handling machinery, which is essential for thyroid hormone synthesis, is also a significant factor in advanced thyroid cancers. Recent advances in molecular understanding have led to the development of novel diagnostic and therapeutic strategies, including the use of genetic markers and targeted therapies.