While a level IIA multi-trial NSCLC study confirmed that patients who received personalized first-line therapy based on their RRM1 and ERCC1 gene expression status had better survival than patients on standard therapy [56], a level IIIF study of a three drug concurrent regimen [57] produced results which were contradictory to previous studies, in that responders had low gene expression levels ERCC1 as expected but high levels of RRM1. This evidence concerns the gene ERCC1 and non-small cell lung carcinoma.