Background: Recepteur d'originenantais (RON) is a receptor tyrosine kinase (RTK) that belongs to the MET proto-oncogene family. The aim of this study was to investigate the expression of RON receptor tyrosine kinase in human non-small cell lung cancer (NSCLC) and its relationship with clinical pathology of NSCLC and prognosis.
Methods: RON protein expression by immunohistochemistry (IHC) in 96 NSCLC specimens was evaluated and compared with the clinical pathology and prognosis, and 20 para-neoplastic tissues were included as controls. RON mRNA and protein expression in 25 fresh tissue samples of lung cancer and 10 normal lung tissues were also analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.
Results: The rate of positive RON expression differed significantly between NSCLC tissues (55.2%, 53/96) and para-neoplastic tissues (5%, 1/20) (P < 0.001). RON protein expression was not found to be associated with gender or age. However, RON expression positively correlated with clinical TNM stage (P = 0.004), histological types (P = 0.001), lymph node metastasis (P = 0.012) and differentiation (P = 0.035). RT-PCR and Western blotting analysis also confirmed that the expression of RON mRNA and protein was significantly increased in the NSCLC tissues versus normal tissues. In addition, RON expression was associated with a poor prognosis for patients with NSCLC (P = 0.045).
Conclusions: The expression of RON protein and mRNA is significant in human NSCLC and low in para-neoplastic and normal tissues. Elevated RON expression may contribute to the occurrence, progression and metastasis of NSCLC, inferring that it could be useful as a new prognostic indicator for patients with NSCLC.