RBL1 and squamous cell carcinoma: The inhibition of tumor development and growth in Rb1+/− mice by eRapa is also consistent with a recent report showing that mTOR inhibition partially alleviated tumor development in an RbF/F;K14creERTM; p107−/− model of squamous cell carcinoma [28], and with several reports demonstrating the effectiveness of rapamycin in mouse cancer models for tumor reduction and life span extension [29-31].