Osteosarcoma and Ewing sarcoma are the most common bone sarcomas of the childhood. Kerbs von de Lungren 6 (KL-6) is a glycoprotein that is expressed on type 2 pneumocytes and bronchial epithelium. Serum KL-6 level can increase in many interstitial pulmonary diseas and lung cancers. Aim of the study is to evaluate the predictive value of serum KL-6 level on malign potential of pulmonary nodules in pediatric patients with bone sarcoma with pulmonary metastasis or with vague pulmonary nodules.

Blood samples were taken from patients with diagnosis of Ewing sarcoma or osteosarcoma at the time of diagnosis or first relapses. Control group was selected from 42 voluntary children without any chronic or acute diseases associated with lung. Serum of the blood samples were separated and frozen at -70 C˚ and KL-6 level was measured via ELISA method. Thorax computed tomography (CT) images of the patients were analyzed to interpret about pulmonary metastasis.

Total 47 patients were included in the study, 19 of the patients were with Ewing sarcoma and 28 with osteosarcoma.Thorax CT revealed pulmonary metastasis in 9 of the patients at first evaluation. KL-6 level of the these patients with pulmonary metastasis was greater than without metastasis (p;0.05) and control group (p;0.019). Patients with pulmonary nodule at any time had significantly higher serum KL-6 level at first evaluation than without metastasis (p; 0.04) and control group (p;0.017).

In our study we found serum KL-6 level higher in patients with pulmonary nodules that relevant with pulmonary sarcoma metastasis than patients without metastasis and healthy control group. Our study also revealed that patients that had pulmonary metastasis during their follow-up also had higher KL-6 level at diagnosis. These results should be proven with more number of patients. Measuring KL-6 level may be used as a marker for early diagnosis of pulmonary sarcoma metastasis.