Investigation of Serum Krebs von den Lungen-6 Level in Patients with Bone Sarcoma and Lung Metastasis

Serum Krebs von den Lungen-6 (KL-6) level increases in interstitial lung disease and lung cancer. The present study investigated whether there was an increase in serum KL-6 levels in patients with bone sarcoma who were considered positive for lung metastasis.

Serum samples were collected from patients diagnosed with Ewing sarcoma and osteosarcoma before starting chemotherapy. The samples were frozen and stored at -80°C, and serum KL-6 level was measured using enzyme-linked immunosorbent assay.

Serum samples of 47 patients and 42 healthy volunteers were evaluated. At the time of diagnosis, 10 patients had pulmonary tumor metastasis. Patients were followed up for a median of 43 months (1-125 months). At the time of diagnosis, the median KL-6 level of patients with lung metastases was 38.15 U/mL (10.6-155.6 U/mL), while the KL-6 level of patients without lung metastases was 15.2 U/mL (10.7-188.3 U/mL). The difference between these 2 groups was borderline significant (P = .051). The median KL-6 value of the control group was 14.85 U/mL (10.3-188.6 U/mL). When the patients with lung metastasis at the time of diagnosis were compared with the healthy control group, the KL-6 level of the patients was statistically significantly higher than the control group (P = .017).

In this pilot study, it was found that serum KL-6 levels were elevated in patients with lung metastasis at the time of diagnosis compared to healthy controls. Serum KL-6 level may be used as an additional parameter to detect pulmonary metastasis, and further studies are needed to confirm this observation.