KRAS and neoplasm: Although we have demonstrated the loss of miR-200, and the activation of Notch and NF-κB signaling pathway in the current animal model; however, there maybe other genetic alterations causing tumor aggressiveness in this compound mice with activated K-ras and Ink4a/Arf deficiency, suggesting that further in-depth studies are needed to investigate the precise molecular mechanism of tumor progression in this mouse model.