Based on the ability of the Bit1 cell death pathway to effectively trigger apoptosis and anoikis in lung cancer cells in vitro (Figures 2A–2C) and the recent report demonstrating that exogenous Bit1 CDD induces apoptosis in human breast tumor xenografts in vivo[19], the level of apoptosis in control and Bit1 knockdown tumor xenografts was evaluated by subjecting serial tumor tissue sections to in situ TUNEL assay (Figures 7D and 7E). This evidence concerns the gene PTRH2 and lung cancer.