Clinical significance of the phosphorylation of MAPK and protein expression of cyclin D1 in human osteosarcoma tissues.

The aim of the present study was to investigate the significance of the phosphorylation of mitogen-activated protein kinase (MAPK) and the protein expression of cyclin D1 in human osteosarcoma tissues. Human osteosarcoma tissue samples were collected from 30 patients, benign bone tumor samples were collected from 30 patients, and normal bone tissues were collected from 10 individuals as controls. Immunohistochemistry was performed to measure the levels of phosphorylated (p)-MAPK and cyclin D1 protein in cases of human osteosarcoma. The results showed that the positive rates of MAPK and cyclin D1 in osteosarcoma were 86.67% (26/30) and 73.00% (22/30), respectively. The positive staining rates of MAPK and cyclin D1 in benign bone tumor tissues were 10.00% (3/30) and 3.30% (1/30), respectively. The positive rate in the normal bone tissues was 0% (0/30), which was significantly lower, compared with that of the cancerous bone tissue. The positive rates of MAPK and cyclin D1 in osteosarcoma were increased (P<0.05), and the expression of cyclin D1 and p‑MAPK were positively correlated. The phosphorylation of MAPK may be important in the development of osteosarcoma, and the overactivation of MAPK may induce high expression of cyclin D1 and induce tumor cells to proliferate continuously.