CEA correlated closely to bone metastasis (TA: P < 0.05, VA: P < 0.01) and NSE had significant correlation with metastasis of bone (TA: P < 0.001, VA: P < 0.01), liver (TA: P < 0.001, VA: P < 0.01), lymph node (TA: P < 0.01, VA: P < 0.01) and mediastinum (TA: P < 0.01, VA: P < 0.05) (Table 1, Additional file 1: Table S1A and B). Here, ENO2 is linked to bone metastasis.