To demonstrate that sample quality of tissues shock frozen or conserved in RNAlater for various lengths of time is equally high, we compared the quality of total RNA as well as the expression of these 5 genes including one housekeeping gene (TBP), 3 genes relevant in NSCLC (ERCC1, EGFR, RRM1) [14–18] and one gene (HIF1) regulated by ischemia at least partially on the mRNA level [19–21] in matched lung tumor samples processed by the various procedures. This evidence concerns the gene ERCC1 and non-small cell lung carcinoma.