In conclusion, in this study, we found a significantly higher WT1 expression level in NSCLC specimens compared to adjacent non-cancer tissues, we demonstrated the proliferation promoting function of WT1 in vitro and in vivo and we identified its oncogenic role in NSCLC via amplification of the transcriptional activity of p-STAT3 that up-regulates downstream genes, including Cyclin D1 and the hypo-phosphorylated retinoblastoma protein (p-pRb). This evidence concerns the gene WT1 and cancer.