Expression of phosphorylated raf kinase inhibitor protein (pRKIP) is a predictor of lung cancer survival
- Equal contributors
1 Unidad de Investigacion en Enferemedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, SSa, Mexico
2 Department of Pathology and Laboratory Medicine, and Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
3 Department of Medicine, Rhode Island Hospital; and The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
4 Unidad de Investigacion Medica en Inmunologia e Infectologia, CMN, La Raza, IMSS Mexico
5 Department of Biostatistics, Department of Human Genetics, and Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
6 Department of Microbiology, Immunology and Molecular Genetics, and Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
BMC Cancer 2011, 11:259 doi:10.1186/1471-2407-11-259Published: 21 June 2011
Raf-1 kinase inhibitor protein (RKIP) has been reported to negatively regulate signal kinases of major survival pathways. RKIP activity is modulated in part by phosphorylation on Serine 153 by protein kinase C, which leads to dissociation of RKIP from Raf-1. RKIP expression is low in many human cancers and represents an indicator of poor prognosis and/or induction of metastasis. The prognostic power has typically been based on total RKIP expression and has not considered the significance of phospho-RKIP.
The present study examined the expression levels of both RKIP and phospho-RKIP in human lung cancer tissue microarray proteomics technology.
Total RKIP and phospho-RKIP expression levels were similar in normal and cancerous tissues. phospho-RKIP levels slightly decreased in metastatic lesions. However, the expression levels of phospho-RKIP, in contrast to total RKIP, displayed significant predictive power for outcome with normal expression of phospho-RKIP predicting a more favorable survival compared to lower levels (P = 0.0118); this was even more pronounced in more senior individuals and in those with early stage lung cancer.
This study examines for the first time, the expression profile of RKIP and phospho-RKIP in lung cancer. Significantly, we found that phospho-RKIP was a predictive indicator of survival.