[Correlations of S100A4 protein expression to invasion and metastasis of non-small cell lung cancer].

BACKGROUND & OBJECTIVE: Metastasis-associated protein S100A4 is overexpressed in many malignant tumor cells; it may play a pivotal role in invasion and metastasis of malignant tumors. This study was to determine the expression of S100A4 in human non-small cell lung cancer (NSCLC), and to investigate its correlations to invasion and metastasis of NSCLC. METHODS: The expression of S100A4 in 41 specimens of NSCLC and 6 specimens of normal lung tissues was detected by SP immunohistochemistry. The correlations of S100A4 to clinicopathologic features of NSCLC were analyzed. RESULTS: The positive rate of S100A4 was significantly higher in NSCLC than in normal lung tissues (70.7% vs. 16.7%, P<0.05), and was significantly higher in adenocarcinoma than in squamous cell carcinoma (90.0% vs. 52.4%, P<0.01). The positive rate of S100A4 was significantly higher in stage III-IV than in stage II and stage I NSCLC (100.0% vs. 66.7% and 30.0%, P<0.01), while there was no obvious difference between the latter 2 groups (P>0.05). The positive rate of S100A4 was significantly higher in NSCLC with lymphatic metastasis than in NSCLC without lymphatic metastasis (90.0% vs. 52.4%, P<0.01), and significantly higher in NSCLC with tumor size of > or = 3 cm than in NSCLC with tumor size of < 3 cm (91.3% vs. 44.4%, P<0.001). The expression of S100A4 was closely related to lymphatic metastasis (r=0.480, P=0.001), and tumor size (r=0.288, P=0.017). No significant correlation was found between the expression of S100A4 and pathologic grade of NSCLC (P>0.05). CONCLUSION: S100A4 expression is up-regulated in NSCLC, and closely related to lymphatic metastasis, TNM stage and tumor size, which suggest an important role of S100A4 in the invasion and metastasis of NSCLC.