OBJECTIVETo identify the differentially expressed genes related to lymphatic metastasis of lung squamous cell carcinoma.

METHODSSpecimens of primary lung squamous cancer tissues and regional lymph nodes were obtained from 10 patients undergoing complete surgical resection of the tumor. The samples were classified into 3 groups, namely the primary tumor with lymphatic metastasis (TxN+, n=5), primary tumor without lymphatic metastasis (TxN-, n=5) and matched tumor cells from the metastatic lymph nodes (N+, n=5). The total RNA extracted from the laser microdissected primary tumor or metastatic nodes was labeled and hybridized with the microarray containing 6 000 known human genes or ESTs. Data analysis was performed using GeneSpring(TM) 6.2 software. Immunohistochemical staining was used to detect the expression of CCL20 in the specimens.

RESULTSA total of 37 genes showed differential expressions between TxN+ and TxN- tissues, among which 8 genes were upregulated and 29 were downregulated in TxN+ group. No genes, however, showed distinct differential expressions between N+ and TxN+ tissues. The expression of CCL20 was significantly higher in TxN- than in TxN+ tissues (P<0.05).

CONCLUSIONThe acquisition of the metastatic phenotype may occur early in the development of lung squamous cancer. The gene expression signature of lung squamous cell carcinoma is valuable to elucidate the molecular mechanisms regarding lymphatic metastasis of the malignancy, and may provide important clues for exploring novel therapeutic targets.