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

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.

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.

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).

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.