nancy of bone, and is a high‐grade malignant mesenchymal tumor with high recurrence and metastatic rates. Increased expression of secreted protein, acidic and rich in cysteine (SPARC) indicates poor prognosis in a number of malig‐

Osteosarcoma is the most common primary malig‐ nancy of bone, and is a high‐grade malignant mesenchymal tumor with high recurrence and metastatic rates. Increased expression of secreted protein, acidic and rich in cysteine (SPARC) indicates poor prognosis in a number of malig‐ nances. However, the expression level of SPARC in human osteosarcoma and its associated mechanism remains unclear. To analyze the expression of SPARC in human osteosarcoma and its potential application in the diagnosis and treatment of osteosarcoma, the clinical records and samples of 20 cases of osteosarcoma were collected. Reverse transcription‐quantita‐ tive polymerase chain reaction (RT‐qPCR) analysis applied to detect SPARC expression levels in osteosarcoma tissues, with normal bone tissue as control. Immunofluorescence detection was used to examine the distribution of SPARC. The association between SPARC level and clinical factors was analyzed. RT‐qPCR (P=0.002) indicated that the SPARC level in osteosarcoma tissues was significantly increased compared with that in normal tissues. Immunofluorescence detection indicated that SPARC was widely distributed in tumor tissues. SPARC protein expression level was positively associated with lung metastasis (P=0.016). The results indicated that SPARC tends to be highly expressed in human osteosarcoma tissues. The expression level of SPARC is associated with lung metas‐ tasis, which may be an indicator of prognosis. Thus, SPARC may be a potential tumor marker and therapeutic target in osteosarcoma.