[Gene expression signature for lymphatic metastasis of human lung adenocarcinoma]

Distant metastasis is a major cause of mortality for patients with lung adenocarcinoma. So far, the mechanism of tumor metastasis is unknown. This study was to screen the gene expression signature in relation to lymphatic metastasis of human lung adenocarcinoma.

Primary lung adenocarcinoma tissues and regional lymph nodes were obtained from 22 patients underwent radical resection. The samples were classified into three groups: 11 cases of primary lung adenocarcinoma without lymphatic metastasis (TxN-), 11 cases of primary lung adenocarcinoma with lymphatic metastasis (TxN+), and 11 cases of the corresponding tumor cells from metastatic lymph nodes(N+). Total RNA was extracted from laser microdissected tumor samples. Adequate RNA starting materials from the primary tumors or metastatic nodes were labeled and then hybridized into the same microarray containing 6000 known human genes or expressed sequence tags (ESTs). After scanning, data analyses were performed using GeneSpring 6.2.

Among 17 differentially expressed genes between the TxN+ and TxN-groups, 12 genes were significantly elevated and five genes were significantly downregulated in the TxN+ group compared with the TxN-group. There were 53 differentially regulated genes between the N+ and TxN+ groups, among which 25 genes were overexpressed and 28 genes were suppressed in the N+ group.

The combination of early oncogenic alterations and later acquisition of a set of genetic alterations may determine the metastatic potential of lung adenocarcinoma.