PTGS2 and neoplasm: Overall, in NSCLC, the rates of COX-2 protein overexpression (detected by IHC), COX-2 mRNA expression (RT–PCR) and COX-2 gene amplification (detected by in situ hybridisation) were respectively, 62.4% (number of evaluable tumours n=833, 51.7% (n=149) and 59.8% (n=254).