RRM1 expression and the clinicopathological characteristics of patients with non-small cell lung cancer treated with gemcitabine

BACKGROUND: The usefulness of ribonucleotide reductase catalytic subunit M1 (RRM1) for predicting the therapeutic effects of gemcitabine-containing chemotherapy in patients with non-small cell lung cancer (NSCLC) remains controversial. RRM1-positive patients show unique clinicopathological features. METHODS: Here, we performed a meta-analysis to systematically evaluate the relationship between RRM1 expression and the clinicopathological characteristics of NSCLC patients treated with gemcitabine-containing regimens. A comprehensive electronic and manual search was performed to identify relevant articles. The pooled relative risk (RR) and 95% CI were used to estimate the relation between the clinicopathological characteristics of NSCLC patients and RRM1 expression. RESULTS: The study included 31 observational studies and 3,667 patients. The analysis showed no significant association between RRM1 expression and pathological type, stage, and smoking status; however, RRM1 positivity was significantly lower in women than in men (43.0% vs 51.7%, RR=0.84, 95% CI: 0.74–0.94, P=0.004). CONCLUSION: The present pooled analyses demonstrated that RRM1 positivity in women with advanced NSCLC was associated with a higher rate of response to gemcitabine-containing regimens. Immunohistochemistry may be valuable to prescreen for RRM1 expression in clinical practice, whereas PCR can be routinely used as a verification method. These findings will help design suitable molecular-targeted therapies for NSCLC.