Validation of RRM1 and PTEN as prognostic parameters of outcome in non-small cell lung cancer

Abstract

7154 Background: RRM1 has important functions in determination of the malignant phenotype. It controls cell proliferation through deoxynucleotide production and metastatic propensity through PTEN induction. It is located in a region of loss of heterozygosity in non-small cell lung cancer (NSCLC), which is a predictor of poor survival. We hypothesized that RRM1 expression would be a significant predictor of outcome in NSCLC. Methods: A retrospective dataset of 49 patients and a prospective dataset of 77 patients with resectable NSCLC were studied. RNA was extracted from tumor and normal lung tissue, and expression of the genes RRM1, PTEN, and RRM2 was determined by real-time quantitative polymerase chain reaction. Results: RRM1 expression was significantly correlated with PTEN and RRM2 expression in both tumor and normal lung tissue. RRM1 and PTEN expression in tumor tissue were highly predictive of overall (p=0.011 and 0.018) and disease-free survival (p=0.002 and 0.026). Patients with high levels of expression lived longer and had disease recurrence later than patients with low levels of RRM1 and PTEN. In a multivariate analysis, high RRM1 expression was predictive of long survival independent of tumor stage, performance status, and weight loss. Conclusion:: RRM1 is a biologically and clinically important determinant of malignant behavior in NSCLC. Knowing the level of expression of this gene adds significant information to management decisions independent of the currently used outcome predictors tumor stage, performance status, and weight loss. Future clinical trials should stratify patients based on expression of this gene to avoid unwanted biases. No significant financial relationships to disclose.