[Research Progress on the Mechanism and Diagnostic Markers of Bone Metastasis 
in Small Cell Lung Cancer].

Small cell lung cancer (SCLC) is a type of lung cancer with high malignant degree, rapid transformation, rapid invasion and metastasis, which is prone to early metastasis and poor prognosis. Bone metastases of SCLC occur in three stages: cancer cells proliferate at the primary site, break through local tissues, enter the blood circulation to form circulating tumor cells (CTCs), reach bone tissue through blood circulation, and take root and germinate to form new tumor sites with the support of the bone microenvironment. However, traditional imaging and pathology examinations have disadvantages such as low sensitivity, high cost and difficulty in implementation. Exploratory studies based on blood marker detection as screening and efficacy evaluation of SCLC bone metastases have been reported in recent years. By reviewing the molecular biological mechanism of SCLC bone metastasis formation, this paper found that conventional diagnostic methods such as imaging and pathological biopsy were inadequate in SCLC bone metastasis. The changes in hyaluronic acid, protein biomarkers, non-coding RNA, and biomarkers in liquid biopsy were earlier than the changes in imaging, which had the advantages of simple operation and good repeatability. It provides a new idea and method for the early diagnosis of SCLC bone metastasis, which is worthy of clinical application.
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