SPP1 and lung cancer: Therefore, our results, together with findings by other groups, suggest that OPN plays a crucial role for tumor growth and/or progression of human lung cancer by interacting with αvβ3 integrin and activating Pim-1 through additional signaling pathways [18], [19], [23], [29], thus resulting in the overexpression of OPN, αvβ3 and Pim-1.