Large scale microarray data integration across 21 major cancer types identified the transcription co-activator PC4 (positive co-factor 4) amongst the 46 common cancer signatures.435,436 It has been reported that PC4 is highly expressed in NSCLC cells and tissues.432 Moreover, PC4 has also been associated with lymphatic metastasis and poor prognosis in lung adenocarcinoma.437 PC4 has been shown to mediate transcriptional activation of several oncogenes. This evidence concerns the gene SUB1 and lung adenocarcinoma.