Pretreatment Red Blood Cell Total Folate Concentration Is Associated With Response to Pemetrexed in Stage IV Nonsquamous Non-Small-cell Lung Cancer

A low pretreatment RBC total folate was associated with an inferior response to pemetrexed-based chemotherapy in stage IV nonsquamous NSCLC. Larger, multicenter studies are needed to validate RBC total folate as a predictive marker of pemetrexed response.