Cells with reduced Arl2 content were found to behave more aggressively, with loss of contact inhibition, ability to grow in multilayer in vitro, enhanced clonogenic or cluster formation potential, gain of survival advantage vis-à-vis their normal counterparts in an in vitro competition assay as well as enhanced tumor growth and reduced spontaneous necrosis tumors in vivo. This evidence concerns the gene ARL2 and neoplasm.