Chen Y, et al. - Researchers systematically assessed the link between ribonucleotide reductase catalytic subunit M1 (RRM1) expression and the clinicopathological features of non-small cell lung cancer (NSCLC) patients treated with gemcitabine-containing regimens in order to ascertain whether RRM1 expression affords a useful predictor of the therapeutic effects of gemcitabine-containing chemotherapy in these patients. They used the pooled relative risk (RR) and 95% CI to estimate the aforementioned link. Overall, they analyzed 31 observational studies with 3,667 patients. In these pooled analyses, a higher rate of response to gemcitabine-containing regimens was reported in relation to RRM1 positivity in women with advanced NSCLC. In clinical practice, immunohistochemistry could have utility to prescreen for RRM1 expression, while for the purpose of verification, PCR can be routinely used.