Predictive value of serum immunosuppressive acidic protein for lung metastasis after amputation of murine osteosarcoma of the lower limb

A spontaneously occurring murine osteosarcoma cell line (POS-1) was inocula ted into the footpads of 88 mice. In 59 mice. the tumor-bearing leg was amp utated at 1, 3, 5. or 7 weeks after inoculation and the mice sacrificed at 9 weeks. Lung metastasis was observed in 82.6-100% of the mice undergoing l eg amputation at 5 or 7 weeks after inoculation. There were no lung metasta sis in the mice amputated at 1 or 3 weeks. The serum immunosuppressive acid ic protein (IAP) concentration showed a significant increase at 5 or 7 week s after inoculation (P < 0.005 and P < 0.0005, respectively). When amputati on was done 5 weeks after inoculation, the serum IAP concentration increase d further to 5.9 times the pre-amputation level 1 week after the amputation . The IAP concentration increased only 1.3-fold in the control group withou t inoculation. Thus, a high serum IAP concentration before amputation and a further increase after amputation were indicators of lung metastasis in th is mouse model of osteosarcoma. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.