Clinical significance of CD151 gene expression in non-small cell lung cancer.

Transmembrane 4 superfamily (TM4SF) is a recently described gene family, and TM4SF members are known to play roles in the signal transduction pathways and to regulate cell activation, development, proliferation, and motility. MRP-1/CD9, KAI1/CD82, and ME491/CD63, members of the TM4SF, have been reported to suppress tumor progression or metastasis. Previously, we showed that MRP-1/CD9 suppressed cell motility and metastatic potential to lungs. Moreover, reduction of MRP-1/CD9 and KAI1/CD82 gene expression was found to be a factor in a poor prognosis for patients with non-small cell lung cancer. However, among TM4SF, CD151 is identical to an existing gene, PETA-3, which may promote tumor metastasis of malignant cells, and its expression may be involved in the malignant progression of cancer. The function of CD151 is opposite that of the metastasis suppressor genes, MRP-1/CD9 and KAI1/CD82. On the basis of these results, we used reverse transcription-PCR and immunohistochemical techniques for a retrospective study of CD151 gene expression in tumor tissues from 145 lung cancer patients; 72 tumors were stage I, 29 stage II, 27 stage IIIA, and 17 stage IIIB. Whereas 86 patients had tumors positive for the CD151 gene, 59 had tumors that were negative for the CD151 gene. The overall survival rate of patients with CD151-positive tumors was much lower than that of CD151-negative patients (51.9% versus 73.1%; P = 0.013). Our findings suggest that high CD151 gene expression in lung cancer may be associated with a poor prognosis. Assessment of CD151 could be instrumental for improvements in lung cancer diagnosis and therapies.