Regenerating gene I alpha (REG1A) is a known growth factor affecting pancreatic islet beta cells. Although REG1A expression also has been observed in various tumors, the correlation between REG1A expression and the clinicopathological characteristics of non-small cell lung cancer (NSCLC) and patient prognosis has not been evaluated.
Methods: We used real-time semi-quantitative reverse transcription polymerase chain reaction to assess REG1A mRNA expression in tumor samples from 86 NSCLC patients. We then correlated REG1A mRNA expression with known clinicopathological factors. We also used immunohistochemical staining to determine the source of REG1A.
Results: Within samples of tumor tissue, the cytosol of tumor cells was stained with anti-REG1A antibody. Cells from normal tissue were not stained. The 5-year over-all survival rate among patients expressing lower levels of REG1A was significantly better than among those expressing higher levels of REG1A (P=0.0031 by log-rank test). Multivariate Cox proportional hazard analyses revealed REG1A (hazard ratio, 2.34; 95% CI, 1.25-5.90; P=0.0055) and pathological stage III (hazard ratio, 3.46; 95% CI, 1.52-14.82; P=0.0012) to be independent factors affecting the 5-year over-all survival rate.
Conclusion: High levels of REG1A expression by tumor cells are an independent predictor of a poor prognosis in patients with NSCLC.