Background and purpose: Osteosarcoma is a primary malignant tumor in bone tissue

mainly in adolescents. The prognosis of patients with lung metastasis is poor. CC chemokine ligand 2 (CCL2) and tis receptor CC chemokine ligand receptor 2 (CCR2) may take part in tumor. Some scholars have confirmed that CCL2 can promote the metastasis process of breast cancer and worsen the prognosis. The main purpose of this article was to st

udy the expression of CCL2 in osteosarcoma tissue and its relationship with prognosis. Methods: GEXSCOPE

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tissue dissociation solution was used to dissociate 11 osteosarcoma samples into single cell suspension. The single cell sequencing library (scRNA-seq) was established by Chromium Single Cell Gene Expression Kit

Gel Bead Kit and Multiplex Kit from 10x Genomics Company. The expression of CCL2 was analyzed by scRNA-seq. The CCL2 level in lesions from tissue microarray was detected in 90 osteosarcoma patients

who were diagnosed and treated in the 6th People’s Hospital Affiliated to Shanghai Jiao Tong University from January 2017 to December 2019

using immunohistochemical method. According to the median value of the CCL2 histochemical score

90 patients were divided into two groups

high expression and low expression. COX regression was used to analyze the CCL2 level and its relationship with clinicopathological characteristics and prognosis of patient. Results: The results of scRNA-seq indicated that CCL2 expression was higher in lung metastasis lesions than in primary tissues. The immunohistochemical results displayed that of the 80 cases

33 had high CCL2 expression level and 47 had low CCL2 expression level. CCL2 expression was associated with clinical stage and lung metastasis (P0.05). There was no significant correlation among the CCL2 level and age

gender

tumor size

pathological type and tumor necrosis rate (P0.05). Conclusion: CCL2 may be one of the poor indicators to predict the metastasis and prognosis of osteosarcoma.