Abstract:Objective To investigate the clinical efficacy and prognostic significance of ribonucleotide reductase M1 (RRM1) expression in peripheral blood of aged patients with advanced non-small cell lung cancer (NSCLC) treated with Gemcitabine. Methods Blood samples were collected from 40 aged patients with advanced NSCLC to investigate the expression level of RRM1 in peripheral blood by real-time quantitative polymerase chain reaction (qRT-PCR). Relationships of the RRM1 expression with clinical characters, efficacy, overall survival time of the patients with aged advanced NSCLC were analyzed. Results There was no correlation between RRM1 expression in peripheral blood and gender, pathological type or TNM stage (P > 0.05). The patients with low expression of RRM1 had higher response rate (35%) and disease control rate (60%) to Gemcitabine than the patients with overexpression of RRM1 (10% and 20%, P < 0.05). The RRM1 low-expression group had longer overall survival time (14.8 m vs. 11.6 m), longer progression-free survival time (4.4 m vs. 3.2 m) and higher 1-year survival rate (76.7% vs. 53.3%) and 2-year survival rate (9.3% vs. 0.0%) than the RRM1 over-expression group (P < 0.05). Conclusions The aged patients with low levels of RRM1 expression in peripheral blood have higher response to chemotherapy and longer survival time. RRM1 expression in peripheral blood is an independet prognostic factor. This study may provide a new option for aged patients with advanced NSCLC who are unable to gain lung tissue for screening of chemotherapeutic drugs.